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alistair23-linux/drivers/tty/serial/serial-tegra.c

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tty: add SPDX identifiers to all remaining files in drivers/tty/ It's good to have SPDX identifiers in all files to make it easier to audit the kernel tree for correct licenses. Update the drivers/tty files files with the correct SPDX license identifier based on the license text in the file itself. The SPDX identifier is a legally binding shorthand, which can be used instead of the full boiler plate text. This work is based on a script and data from Thomas Gleixner, Philippe Ombredanne, and Kate Stewart. Cc: Jiri Slaby <jslaby@suse.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: David Sterba <dsterba@suse.com> Cc: James Hogan <jhogan@kernel.org> Cc: Rob Herring <robh@kernel.org> Cc: Eric Anholt <eric@anholt.net> Cc: Stefan Wahren <stefan.wahren@i2se.com> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Ray Jui <rjui@broadcom.com> Cc: Scott Branden <sbranden@broadcom.com> Cc: bcm-kernel-feedback-list@broadcom.com Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Joachim Eastwood <manabian@gmail.com> Cc: Matthias Brugger <matthias.bgg@gmail.com> Cc: Masahiro Yamada <yamada.masahiro@socionext.com> Cc: Tobias Klauser <tklauser@distanz.ch> Cc: Russell King <linux@armlinux.org.uk> Cc: Vineet Gupta <vgupta@synopsys.com> Cc: Richard Genoud <richard.genoud@gmail.com> Cc: Alexander Shiyan <shc_work@mail.ru> Cc: Baruch Siach <baruch@tkos.co.il> Cc: "Maciej W. Rozycki" <macro@linux-mips.org> Cc: "Uwe Kleine-König" <kernel@pengutronix.de> Cc: Pat Gefre <pfg@sgi.com> Cc: "Guilherme G. Piccoli" <gpiccoli@linux.vnet.ibm.com> Cc: Jason Wessel <jason.wessel@windriver.com> Cc: Vladimir Zapolskiy <vz@mleia.com> Cc: Sylvain Lemieux <slemieux.tyco@gmail.com> Cc: Carlo Caione <carlo@caione.org> Cc: Kevin Hilman <khilman@baylibre.com> Cc: Liviu Dudau <liviu.dudau@arm.com> Cc: Sudeep Holla <sudeep.holla@arm.com> Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com> Cc: Andy Gross <andy.gross@linaro.org> Cc: David Brown <david.brown@linaro.org> Cc: "Andreas Färber" <afaerber@suse.de> Cc: Kevin Cernekee <cernekee@gmail.com> Cc: Laxman Dewangan <ldewangan@nvidia.com> Cc: Thierry Reding <thierry.reding@gmail.com> Cc: Jonathan Hunter <jonathanh@nvidia.com> Cc: Barry Song <baohua@kernel.org> Cc: Patrice Chotard <patrice.chotard@st.com> Cc: Maxime Coquelin <mcoquelin.stm32@gmail.com> Cc: Alexandre Torgue <alexandre.torgue@st.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Peter Korsgaard <jacmet@sunsite.dk> Cc: Timur Tabi <timur@tabi.org> Cc: Tony Prisk <linux@prisktech.co.nz> Cc: Michal Simek <michal.simek@xilinx.com> Cc: "Sören Brinkmann" <soren.brinkmann@xilinx.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Kate Stewart <kstewart@linuxfoundation.org> Cc: Philippe Ombredanne <pombredanne@nexb.com> Cc: Jiri Slaby <jslaby@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-11-06 10:11:51 -07:00
// SPDX-License-Identifier: GPL-2.0
/*
* serial_tegra.c
*
* High-speed serial driver for NVIDIA Tegra SoCs
*
* Copyright (c) 2012-2019, NVIDIA CORPORATION. All rights reserved.
*
* Author: Laxman Dewangan <ldewangan@nvidia.com>
*/
#include <linux/clk.h>
#include <linux/debugfs.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/dmapool.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/pagemap.h>
#include <linux/platform_device.h>
#include <linux/reset.h>
#include <linux/serial.h>
#include <linux/serial_8250.h>
#include <linux/serial_core.h>
#include <linux/serial_reg.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/termios.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#define TEGRA_UART_TYPE "TEGRA_UART"
#define TX_EMPTY_STATUS (UART_LSR_TEMT | UART_LSR_THRE)
#define BYTES_TO_ALIGN(x) ((unsigned long)(x) & 0x3)
#define TEGRA_UART_RX_DMA_BUFFER_SIZE 4096
#define TEGRA_UART_LSR_TXFIFO_FULL 0x100
#define TEGRA_UART_IER_EORD 0x20
#define TEGRA_UART_MCR_RTS_EN 0x40
#define TEGRA_UART_MCR_CTS_EN 0x20
#define TEGRA_UART_LSR_ANY (UART_LSR_OE | UART_LSR_BI | \
UART_LSR_PE | UART_LSR_FE)
#define TEGRA_UART_IRDA_CSR 0x08
#define TEGRA_UART_SIR_ENABLED 0x80
#define TEGRA_UART_TX_PIO 1
#define TEGRA_UART_TX_DMA 2
#define TEGRA_UART_MIN_DMA 16
#define TEGRA_UART_FIFO_SIZE 32
/*
* Tx fifo trigger level setting in tegra uart is in
* reverse way then conventional uart.
*/
#define TEGRA_UART_TX_TRIG_16B 0x00
#define TEGRA_UART_TX_TRIG_8B 0x10
#define TEGRA_UART_TX_TRIG_4B 0x20
#define TEGRA_UART_TX_TRIG_1B 0x30
#define TEGRA_UART_MAXIMUM 8
/* Default UART setting when started: 115200 no parity, stop, 8 data bits */
#define TEGRA_UART_DEFAULT_BAUD 115200
#define TEGRA_UART_DEFAULT_LSR UART_LCR_WLEN8
/* Tx transfer mode */
#define TEGRA_TX_PIO 1
#define TEGRA_TX_DMA 2
#define TEGRA_UART_FCR_IIR_FIFO_EN 0x40
/**
* tegra_uart_chip_data: SOC specific data.
*
* @tx_fifo_full_status: Status flag available for checking tx fifo full.
* @allow_txfifo_reset_fifo_mode: allow_tx fifo reset with fifo mode or not.
* Tegra30 does not allow this.
* @support_clk_src_div: Clock source support the clock divider.
*/
struct tegra_uart_chip_data {
bool tx_fifo_full_status;
bool allow_txfifo_reset_fifo_mode;
bool support_clk_src_div;
bool fifo_mode_enable_status;
int uart_max_port;
int max_dma_burst_bytes;
int error_tolerance_low_range;
int error_tolerance_high_range;
};
struct tegra_baud_tolerance {
u32 lower_range_baud;
u32 upper_range_baud;
s32 tolerance;
};
struct tegra_uart_port {
struct uart_port uport;
const struct tegra_uart_chip_data *cdata;
struct clk *uart_clk;
struct reset_control *rst;
unsigned int current_baud;
/* Register shadow */
unsigned long fcr_shadow;
unsigned long mcr_shadow;
unsigned long lcr_shadow;
unsigned long ier_shadow;
bool rts_active;
int tx_in_progress;
unsigned int tx_bytes;
bool enable_modem_interrupt;
bool rx_timeout;
int rx_in_progress;
int symb_bit;
struct dma_chan *rx_dma_chan;
struct dma_chan *tx_dma_chan;
dma_addr_t rx_dma_buf_phys;
dma_addr_t tx_dma_buf_phys;
unsigned char *rx_dma_buf_virt;
unsigned char *tx_dma_buf_virt;
struct dma_async_tx_descriptor *tx_dma_desc;
struct dma_async_tx_descriptor *rx_dma_desc;
dma_cookie_t tx_cookie;
dma_cookie_t rx_cookie;
unsigned int tx_bytes_requested;
unsigned int rx_bytes_requested;
struct tegra_baud_tolerance *baud_tolerance;
int n_adjustable_baud_rates;
int required_rate;
int configured_rate;
bool use_rx_pio;
bool use_tx_pio;
};
static void tegra_uart_start_next_tx(struct tegra_uart_port *tup);
static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup);
static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup,
bool dma_to_memory);
static inline unsigned long tegra_uart_read(struct tegra_uart_port *tup,
unsigned long reg)
{
return readl(tup->uport.membase + (reg << tup->uport.regshift));
}
static inline void tegra_uart_write(struct tegra_uart_port *tup, unsigned val,
unsigned long reg)
{
writel(val, tup->uport.membase + (reg << tup->uport.regshift));
}
static inline struct tegra_uart_port *to_tegra_uport(struct uart_port *u)
{
return container_of(u, struct tegra_uart_port, uport);
}
static unsigned int tegra_uart_get_mctrl(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
/*
* RI - Ring detector is active
* CD/DCD/CAR - Carrier detect is always active. For some reason
* linux has different names for carrier detect.
* DSR - Data Set ready is active as the hardware doesn't support it.
* Don't know if the linux support this yet?
* CTS - Clear to send. Always set to active, as the hardware handles
* CTS automatically.
*/
if (tup->enable_modem_interrupt)
return TIOCM_RI | TIOCM_CD | TIOCM_DSR | TIOCM_CTS;
return TIOCM_CTS;
}
static void set_rts(struct tegra_uart_port *tup, bool active)
{
unsigned long mcr;
mcr = tup->mcr_shadow;
if (active)
mcr |= TEGRA_UART_MCR_RTS_EN;
else
mcr &= ~TEGRA_UART_MCR_RTS_EN;
if (mcr != tup->mcr_shadow) {
tegra_uart_write(tup, mcr, UART_MCR);
tup->mcr_shadow = mcr;
}
}
static void set_dtr(struct tegra_uart_port *tup, bool active)
{
unsigned long mcr;
mcr = tup->mcr_shadow;
if (active)
mcr |= UART_MCR_DTR;
else
mcr &= ~UART_MCR_DTR;
if (mcr != tup->mcr_shadow) {
tegra_uart_write(tup, mcr, UART_MCR);
tup->mcr_shadow = mcr;
}
}
static void set_loopbk(struct tegra_uart_port *tup, bool active)
{
unsigned long mcr = tup->mcr_shadow;
if (active)
mcr |= UART_MCR_LOOP;
else
mcr &= ~UART_MCR_LOOP;
if (mcr != tup->mcr_shadow) {
tegra_uart_write(tup, mcr, UART_MCR);
tup->mcr_shadow = mcr;
}
}
static void tegra_uart_set_mctrl(struct uart_port *u, unsigned int mctrl)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
int enable;
tup->rts_active = !!(mctrl & TIOCM_RTS);
set_rts(tup, tup->rts_active);
enable = !!(mctrl & TIOCM_DTR);
set_dtr(tup, enable);
enable = !!(mctrl & TIOCM_LOOP);
set_loopbk(tup, enable);
}
static void tegra_uart_break_ctl(struct uart_port *u, int break_ctl)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
unsigned long lcr;
lcr = tup->lcr_shadow;
if (break_ctl)
lcr |= UART_LCR_SBC;
else
lcr &= ~UART_LCR_SBC;
tegra_uart_write(tup, lcr, UART_LCR);
tup->lcr_shadow = lcr;
}
/**
* tegra_uart_wait_cycle_time: Wait for N UART clock periods
*
* @tup: Tegra serial port data structure.
* @cycles: Number of clock periods to wait.
*
* Tegra UARTs are clocked at 16X the baud/bit rate and hence the UART
* clock speed is 16X the current baud rate.
*/
static void tegra_uart_wait_cycle_time(struct tegra_uart_port *tup,
unsigned int cycles)
{
if (tup->current_baud)
udelay(DIV_ROUND_UP(cycles * 1000000, tup->current_baud * 16));
}
/* Wait for a symbol-time. */
static void tegra_uart_wait_sym_time(struct tegra_uart_port *tup,
unsigned int syms)
{
if (tup->current_baud)
udelay(DIV_ROUND_UP(syms * tup->symb_bit * 1000000,
tup->current_baud));
}
static int tegra_uart_wait_fifo_mode_enabled(struct tegra_uart_port *tup)
{
unsigned long iir;
unsigned int tmout = 100;
do {
iir = tegra_uart_read(tup, UART_IIR);
if (iir & TEGRA_UART_FCR_IIR_FIFO_EN)
return 0;
udelay(1);
} while (--tmout);
return -ETIMEDOUT;
}
static void tegra_uart_fifo_reset(struct tegra_uart_port *tup, u8 fcr_bits)
{
unsigned long fcr = tup->fcr_shadow;
unsigned int lsr, tmout = 10000;
if (tup->rts_active)
set_rts(tup, false);
if (tup->cdata->allow_txfifo_reset_fifo_mode) {
fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
tegra_uart_write(tup, fcr, UART_FCR);
} else {
fcr &= ~UART_FCR_ENABLE_FIFO;
tegra_uart_write(tup, fcr, UART_FCR);
udelay(60);
fcr |= fcr_bits & (UART_FCR_CLEAR_RCVR | UART_FCR_CLEAR_XMIT);
tegra_uart_write(tup, fcr, UART_FCR);
fcr |= UART_FCR_ENABLE_FIFO;
tegra_uart_write(tup, fcr, UART_FCR);
if (tup->cdata->fifo_mode_enable_status)
tegra_uart_wait_fifo_mode_enabled(tup);
}
/* Dummy read to ensure the write is posted */
tegra_uart_read(tup, UART_SCR);
/*
* For all tegra devices (up to t210), there is a hardware issue that
* requires software to wait for 32 UART clock periods for the flush
* to propagate, otherwise data could be lost.
*/
tegra_uart_wait_cycle_time(tup, 32);
do {
lsr = tegra_uart_read(tup, UART_LSR);
if ((lsr | UART_LSR_TEMT) && !(lsr & UART_LSR_DR))
break;
udelay(1);
} while (--tmout);
if (tup->rts_active)
set_rts(tup, true);
}
static long tegra_get_tolerance_rate(struct tegra_uart_port *tup,
unsigned int baud, long rate)
{
int i;
for (i = 0; i < tup->n_adjustable_baud_rates; ++i) {
if (baud >= tup->baud_tolerance[i].lower_range_baud &&
baud <= tup->baud_tolerance[i].upper_range_baud)
return (rate + (rate *
tup->baud_tolerance[i].tolerance) / 10000);
}
return rate;
}
static int tegra_check_rate_in_range(struct tegra_uart_port *tup)
{
long diff;
diff = ((long)(tup->configured_rate - tup->required_rate) * 10000)
/ tup->required_rate;
if (diff < (tup->cdata->error_tolerance_low_range * 100) ||
diff > (tup->cdata->error_tolerance_high_range * 100)) {
dev_err(tup->uport.dev,
"configured baud rate is out of range by %ld", diff);
return -EIO;
}
return 0;
}
static int tegra_set_baudrate(struct tegra_uart_port *tup, unsigned int baud)
{
unsigned long rate;
unsigned int divisor;
unsigned long lcr;
unsigned long flags;
int ret;
if (tup->current_baud == baud)
return 0;
if (tup->cdata->support_clk_src_div) {
rate = baud * 16;
tup->required_rate = rate;
if (tup->n_adjustable_baud_rates)
rate = tegra_get_tolerance_rate(tup, baud, rate);
ret = clk_set_rate(tup->uart_clk, rate);
if (ret < 0) {
dev_err(tup->uport.dev,
"clk_set_rate() failed for rate %lu\n", rate);
return ret;
}
tup->configured_rate = clk_get_rate(tup->uart_clk);
divisor = 1;
ret = tegra_check_rate_in_range(tup);
if (ret < 0)
return ret;
} else {
rate = clk_get_rate(tup->uart_clk);
divisor = DIV_ROUND_CLOSEST(rate, baud * 16);
}
spin_lock_irqsave(&tup->uport.lock, flags);
lcr = tup->lcr_shadow;
lcr |= UART_LCR_DLAB;
tegra_uart_write(tup, lcr, UART_LCR);
tegra_uart_write(tup, divisor & 0xFF, UART_TX);
tegra_uart_write(tup, ((divisor >> 8) & 0xFF), UART_IER);
lcr &= ~UART_LCR_DLAB;
tegra_uart_write(tup, lcr, UART_LCR);
/* Dummy read to ensure the write is posted */
tegra_uart_read(tup, UART_SCR);
spin_unlock_irqrestore(&tup->uport.lock, flags);
tup->current_baud = baud;
/* wait two character intervals at new rate */
tegra_uart_wait_sym_time(tup, 2);
return 0;
}
static char tegra_uart_decode_rx_error(struct tegra_uart_port *tup,
unsigned long lsr)
{
char flag = TTY_NORMAL;
if (unlikely(lsr & TEGRA_UART_LSR_ANY)) {
if (lsr & UART_LSR_OE) {
/* Overrrun error */
flag = TTY_OVERRUN;
tup->uport.icount.overrun++;
dev_err(tup->uport.dev, "Got overrun errors\n");
} else if (lsr & UART_LSR_PE) {
/* Parity error */
flag = TTY_PARITY;
tup->uport.icount.parity++;
dev_err(tup->uport.dev, "Got Parity errors\n");
} else if (lsr & UART_LSR_FE) {
flag = TTY_FRAME;
tup->uport.icount.frame++;
dev_err(tup->uport.dev, "Got frame errors\n");
} else if (lsr & UART_LSR_BI) {
/*
* Break error
* If FIFO read error without any data, reset Rx FIFO
*/
if (!(lsr & UART_LSR_DR) && (lsr & UART_LSR_FIFOE))
tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_RCVR);
if (tup->uport.ignore_status_mask & UART_LSR_BI)
return TTY_BREAK;
flag = TTY_BREAK;
tup->uport.icount.brk++;
dev_dbg(tup->uport.dev, "Got Break\n");
}
uart_insert_char(&tup->uport, lsr, UART_LSR_OE, 0, flag);
}
return flag;
}
static int tegra_uart_request_port(struct uart_port *u)
{
return 0;
}
static void tegra_uart_release_port(struct uart_port *u)
{
/* Nothing to do here */
}
static void tegra_uart_fill_tx_fifo(struct tegra_uart_port *tup, int max_bytes)
{
struct circ_buf *xmit = &tup->uport.state->xmit;
int i;
for (i = 0; i < max_bytes; i++) {
BUG_ON(uart_circ_empty(xmit));
if (tup->cdata->tx_fifo_full_status) {
unsigned long lsr = tegra_uart_read(tup, UART_LSR);
if ((lsr & TEGRA_UART_LSR_TXFIFO_FULL))
break;
}
tegra_uart_write(tup, xmit->buf[xmit->tail], UART_TX);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
tup->uport.icount.tx++;
}
}
static void tegra_uart_start_pio_tx(struct tegra_uart_port *tup,
unsigned int bytes)
{
if (bytes > TEGRA_UART_MIN_DMA)
bytes = TEGRA_UART_MIN_DMA;
tup->tx_in_progress = TEGRA_UART_TX_PIO;
tup->tx_bytes = bytes;
tup->ier_shadow |= UART_IER_THRI;
tegra_uart_write(tup, tup->ier_shadow, UART_IER);
}
static void tegra_uart_tx_dma_complete(void *args)
{
struct tegra_uart_port *tup = args;
struct circ_buf *xmit = &tup->uport.state->xmit;
struct dma_tx_state state;
unsigned long flags;
unsigned int count;
dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
count = tup->tx_bytes_requested - state.residue;
async_tx_ack(tup->tx_dma_desc);
spin_lock_irqsave(&tup->uport.lock, flags);
xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
tup->tx_in_progress = 0;
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&tup->uport);
tegra_uart_start_next_tx(tup);
spin_unlock_irqrestore(&tup->uport.lock, flags);
}
static int tegra_uart_start_tx_dma(struct tegra_uart_port *tup,
unsigned long count)
{
struct circ_buf *xmit = &tup->uport.state->xmit;
dma_addr_t tx_phys_addr;
dma_sync_single_for_device(tup->uport.dev, tup->tx_dma_buf_phys,
UART_XMIT_SIZE, DMA_TO_DEVICE);
tup->tx_bytes = count & ~(0xF);
tx_phys_addr = tup->tx_dma_buf_phys + xmit->tail;
tup->tx_dma_desc = dmaengine_prep_slave_single(tup->tx_dma_chan,
tx_phys_addr, tup->tx_bytes, DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT);
if (!tup->tx_dma_desc) {
dev_err(tup->uport.dev, "Not able to get desc for Tx\n");
return -EIO;
}
tup->tx_dma_desc->callback = tegra_uart_tx_dma_complete;
tup->tx_dma_desc->callback_param = tup;
tup->tx_in_progress = TEGRA_UART_TX_DMA;
tup->tx_bytes_requested = tup->tx_bytes;
tup->tx_cookie = dmaengine_submit(tup->tx_dma_desc);
dma_async_issue_pending(tup->tx_dma_chan);
return 0;
}
static void tegra_uart_start_next_tx(struct tegra_uart_port *tup)
{
unsigned long tail;
unsigned long count;
struct circ_buf *xmit = &tup->uport.state->xmit;
if (!tup->current_baud)
return;
tail = (unsigned long)&xmit->buf[xmit->tail];
count = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE);
if (!count)
return;
if (tup->use_tx_pio || count < TEGRA_UART_MIN_DMA)
tegra_uart_start_pio_tx(tup, count);
else if (BYTES_TO_ALIGN(tail) > 0)
tegra_uart_start_pio_tx(tup, BYTES_TO_ALIGN(tail));
else
tegra_uart_start_tx_dma(tup, count);
}
/* Called by serial core driver with u->lock taken. */
static void tegra_uart_start_tx(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
struct circ_buf *xmit = &u->state->xmit;
if (!uart_circ_empty(xmit) && !tup->tx_in_progress)
tegra_uart_start_next_tx(tup);
}
static unsigned int tegra_uart_tx_empty(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
unsigned int ret = 0;
unsigned long flags;
spin_lock_irqsave(&u->lock, flags);
if (!tup->tx_in_progress) {
unsigned long lsr = tegra_uart_read(tup, UART_LSR);
if ((lsr & TX_EMPTY_STATUS) == TX_EMPTY_STATUS)
ret = TIOCSER_TEMT;
}
spin_unlock_irqrestore(&u->lock, flags);
return ret;
}
static void tegra_uart_stop_tx(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
struct circ_buf *xmit = &tup->uport.state->xmit;
struct dma_tx_state state;
unsigned int count;
if (tup->tx_in_progress != TEGRA_UART_TX_DMA)
return;
dmaengine_terminate_all(tup->tx_dma_chan);
dmaengine_tx_status(tup->tx_dma_chan, tup->tx_cookie, &state);
count = tup->tx_bytes_requested - state.residue;
async_tx_ack(tup->tx_dma_desc);
xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
tup->tx_in_progress = 0;
}
static void tegra_uart_handle_tx_pio(struct tegra_uart_port *tup)
{
struct circ_buf *xmit = &tup->uport.state->xmit;
tegra_uart_fill_tx_fifo(tup, tup->tx_bytes);
tup->tx_in_progress = 0;
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&tup->uport);
tegra_uart_start_next_tx(tup);
}
static void tegra_uart_handle_rx_pio(struct tegra_uart_port *tup,
struct tty_port *tty)
{
do {
char flag = TTY_NORMAL;
unsigned long lsr = 0;
unsigned char ch;
lsr = tegra_uart_read(tup, UART_LSR);
if (!(lsr & UART_LSR_DR))
break;
flag = tegra_uart_decode_rx_error(tup, lsr);
if (flag != TTY_NORMAL)
continue;
ch = (unsigned char) tegra_uart_read(tup, UART_RX);
tup->uport.icount.rx++;
if (uart_handle_sysrq_char(&tup->uport, ch))
continue;
if (tup->uport.ignore_status_mask & UART_LSR_DR)
continue;
if (tty)
tty_insert_flip_char(tty, ch, flag);
} while (1);
}
static void tegra_uart_copy_rx_to_tty(struct tegra_uart_port *tup,
struct tty_port *tty,
unsigned int count)
{
int copied;
/* If count is zero, then there is no data to be copied */
if (!count)
return;
tup->uport.icount.rx += count;
if (!tty) {
dev_err(tup->uport.dev, "No tty port\n");
return;
}
if (tup->uport.ignore_status_mask & UART_LSR_DR)
return;
dma_sync_single_for_cpu(tup->uport.dev, tup->rx_dma_buf_phys,
TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_FROM_DEVICE);
copied = tty_insert_flip_string(tty,
((unsigned char *)(tup->rx_dma_buf_virt)), count);
if (copied != count) {
WARN_ON(1);
dev_err(tup->uport.dev, "RxData copy to tty layer failed\n");
}
dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
TEGRA_UART_RX_DMA_BUFFER_SIZE, DMA_TO_DEVICE);
}
static void tegra_uart_rx_buffer_push(struct tegra_uart_port *tup,
unsigned int residue)
{
struct tty_port *port = &tup->uport.state->port;
struct tty_struct *tty = tty_port_tty_get(port);
unsigned int count;
async_tx_ack(tup->rx_dma_desc);
count = tup->rx_bytes_requested - residue;
/* If we are here, DMA is stopped */
tegra_uart_copy_rx_to_tty(tup, port, count);
tegra_uart_handle_rx_pio(tup, port);
if (tty) {
tty_flip_buffer_push(port);
tty_kref_put(tty);
}
}
static void tegra_uart_rx_dma_complete(void *args)
{
struct tegra_uart_port *tup = args;
struct uart_port *u = &tup->uport;
unsigned long flags;
serial: tegra: handle race condition on uart rx side The tegra serial driver has two paths through which receive data is copied up to the tty layer. These are: 1. DMA completion callback 2. UART RX interrupt A UART RX interrupt occurs for either RX_TIMEOUT (data has been sitting in the Rx FIFO for more than 4 character times without being read because there is not enough data to reach the trigger level), End of Receive Data event (receiver detects that data stops coming in for more than 4 character times) or a receive error. In the RX interrupt path, the following happens ... - All RX DMA transfers are stopped - Any data in the DMA buffer and RX FIFO are copied up to the tty layer. - DMA is restarted/primed for the RX path In the DMA completion callback, the DMA buffer is copied up to the tty layer but there is no check to see if the RX interrupt could have occurred between the DMA interrupt firing the the DMA callback running. Hence, if a RX interrupt was to occur shortly after the DMA completion interrupt, it is possible that the RX interrupt path has already copied the DMA buffer before the DMA callback has been called. Therefore, when the DMA callback is called, if the DMA is already in-progress, then this indicates that the UART RX interrupt has already occurred and there is nothing to do in the DMA callback. This race condition can cause duplicated data to be received. Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com> [jonathanh@nvidia.com: Moved async_tx_ack() call to after check to see if DMA has completed because if the DMA is in progress we do not need to ACK yet. Changed the print from dev_info to dev_debug. Updated changelog to add more commentary on the race condition based upon feedback from author.] Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-05 08:17:55 -06:00
struct dma_tx_state state;
enum dma_status status;
spin_lock_irqsave(&u->lock, flags);
serial: tegra: handle race condition on uart rx side The tegra serial driver has two paths through which receive data is copied up to the tty layer. These are: 1. DMA completion callback 2. UART RX interrupt A UART RX interrupt occurs for either RX_TIMEOUT (data has been sitting in the Rx FIFO for more than 4 character times without being read because there is not enough data to reach the trigger level), End of Receive Data event (receiver detects that data stops coming in for more than 4 character times) or a receive error. In the RX interrupt path, the following happens ... - All RX DMA transfers are stopped - Any data in the DMA buffer and RX FIFO are copied up to the tty layer. - DMA is restarted/primed for the RX path In the DMA completion callback, the DMA buffer is copied up to the tty layer but there is no check to see if the RX interrupt could have occurred between the DMA interrupt firing the the DMA callback running. Hence, if a RX interrupt was to occur shortly after the DMA completion interrupt, it is possible that the RX interrupt path has already copied the DMA buffer before the DMA callback has been called. Therefore, when the DMA callback is called, if the DMA is already in-progress, then this indicates that the UART RX interrupt has already occurred and there is nothing to do in the DMA callback. This race condition can cause duplicated data to be received. Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com> [jonathanh@nvidia.com: Moved async_tx_ack() call to after check to see if DMA has completed because if the DMA is in progress we do not need to ACK yet. Changed the print from dev_info to dev_debug. Updated changelog to add more commentary on the race condition based upon feedback from author.] Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-05 08:17:55 -06:00
status = dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
if (status == DMA_IN_PROGRESS) {
dev_dbg(tup->uport.dev, "RX DMA is in progress\n");
goto done;
}
/* Deactivate flow control to stop sender */
if (tup->rts_active)
set_rts(tup, false);
tegra_uart_rx_buffer_push(tup, 0);
tegra_uart_start_rx_dma(tup);
/* Activate flow control to start transfer */
if (tup->rts_active)
set_rts(tup, true);
serial: tegra: handle race condition on uart rx side The tegra serial driver has two paths through which receive data is copied up to the tty layer. These are: 1. DMA completion callback 2. UART RX interrupt A UART RX interrupt occurs for either RX_TIMEOUT (data has been sitting in the Rx FIFO for more than 4 character times without being read because there is not enough data to reach the trigger level), End of Receive Data event (receiver detects that data stops coming in for more than 4 character times) or a receive error. In the RX interrupt path, the following happens ... - All RX DMA transfers are stopped - Any data in the DMA buffer and RX FIFO are copied up to the tty layer. - DMA is restarted/primed for the RX path In the DMA completion callback, the DMA buffer is copied up to the tty layer but there is no check to see if the RX interrupt could have occurred between the DMA interrupt firing the the DMA callback running. Hence, if a RX interrupt was to occur shortly after the DMA completion interrupt, it is possible that the RX interrupt path has already copied the DMA buffer before the DMA callback has been called. Therefore, when the DMA callback is called, if the DMA is already in-progress, then this indicates that the UART RX interrupt has already occurred and there is nothing to do in the DMA callback. This race condition can cause duplicated data to be received. Signed-off-by: Shardar Shariff Md <smohammed@nvidia.com> [jonathanh@nvidia.com: Moved async_tx_ack() call to after check to see if DMA has completed because if the DMA is in progress we do not need to ACK yet. Changed the print from dev_info to dev_debug. Updated changelog to add more commentary on the race condition based upon feedback from author.] Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-05-05 08:17:55 -06:00
done:
spin_unlock_irqrestore(&u->lock, flags);
}
serial: tegra: Handle another RX race condition Commit 853a699739fe ("serial: tegra: handle race condition on uart rx side") attempted to fix a race condition between the RX end of transmission interrupt and RX DMA completion callback. Despite this fix there is still another case where these two paths can race and result in duplicated data. The race condition is as follows: 1. DMA completion interrupt occurs and schedules tasklet to call DMA callback. 2. DMA callback for the UART driver starts to execute. This will copy the data from the DMA buffer and restart the DMA. This is done under uart port spinlock. 3. During the callback, UART interrupt is raised for end of receive. The UART ISR runs and waits to acquire port spinlock held by the DMA callback. 4. DMA callback gives up spinlock after copying the data, but before restarting DMA. 5. UART ISR acquires the spin lock and reads the same DMA buffer because DMA has not been restarted yet. The release of the spinlock during the DMA callback was introduced by commit 9b88748b362c ("tty: serial: tegra: drop uart_port->lock before calling tty_flip_buffer_push()") to fix a spinlock lock-up issue when calling tty_flip_buffer_push(). However, since then commit a9c3f68f3cd8 ("tty: Fix low_latency BUG") migrated tty_flip_buffer_push() to always use a workqueue, allowing tty_flip_buffer_push() to be called from within atomic sections. Therefore, we can remove the unlocking of the spinlock from the DMA callback and UART ISR and this will ensure that the race condition no longer occurs. Reported-by: Christopher Freeman <cfreeman@nvidia.com> Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-09 07:49:59 -06:00
static void tegra_uart_handle_rx_dma(struct tegra_uart_port *tup)
{
struct dma_tx_state state;
/* Deactivate flow control to stop sender */
if (tup->rts_active)
set_rts(tup, false);
dmaengine_terminate_all(tup->rx_dma_chan);
dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
tegra_uart_rx_buffer_push(tup, state.residue);
tegra_uart_start_rx_dma(tup);
if (tup->rts_active)
set_rts(tup, true);
}
static int tegra_uart_start_rx_dma(struct tegra_uart_port *tup)
{
unsigned int count = TEGRA_UART_RX_DMA_BUFFER_SIZE;
tup->rx_dma_desc = dmaengine_prep_slave_single(tup->rx_dma_chan,
tup->rx_dma_buf_phys, count, DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT);
if (!tup->rx_dma_desc) {
dev_err(tup->uport.dev, "Not able to get desc for Rx\n");
return -EIO;
}
tup->rx_dma_desc->callback = tegra_uart_rx_dma_complete;
tup->rx_dma_desc->callback_param = tup;
dma_sync_single_for_device(tup->uport.dev, tup->rx_dma_buf_phys,
count, DMA_TO_DEVICE);
tup->rx_bytes_requested = count;
tup->rx_cookie = dmaengine_submit(tup->rx_dma_desc);
dma_async_issue_pending(tup->rx_dma_chan);
return 0;
}
static void tegra_uart_handle_modem_signal_change(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
unsigned long msr;
msr = tegra_uart_read(tup, UART_MSR);
if (!(msr & UART_MSR_ANY_DELTA))
return;
if (msr & UART_MSR_TERI)
tup->uport.icount.rng++;
if (msr & UART_MSR_DDSR)
tup->uport.icount.dsr++;
/* We may only get DDCD when HW init and reset */
if (msr & UART_MSR_DDCD)
uart_handle_dcd_change(&tup->uport, msr & UART_MSR_DCD);
/* Will start/stop_tx accordingly */
if (msr & UART_MSR_DCTS)
uart_handle_cts_change(&tup->uport, msr & UART_MSR_CTS);
}
static void do_handle_rx_pio(struct tegra_uart_port *tup)
{
struct tty_struct *tty = tty_port_tty_get(&tup->uport.state->port);
struct tty_port *port = &tup->uport.state->port;
tegra_uart_handle_rx_pio(tup, port);
if (tty) {
tty_flip_buffer_push(port);
tty_kref_put(tty);
}
}
static irqreturn_t tegra_uart_isr(int irq, void *data)
{
struct tegra_uart_port *tup = data;
struct uart_port *u = &tup->uport;
unsigned long iir;
unsigned long ier;
bool is_rx_int = false;
unsigned long flags;
spin_lock_irqsave(&u->lock, flags);
while (1) {
iir = tegra_uart_read(tup, UART_IIR);
if (iir & UART_IIR_NO_INT) {
if (!tup->use_rx_pio && is_rx_int) {
serial: tegra: Handle another RX race condition Commit 853a699739fe ("serial: tegra: handle race condition on uart rx side") attempted to fix a race condition between the RX end of transmission interrupt and RX DMA completion callback. Despite this fix there is still another case where these two paths can race and result in duplicated data. The race condition is as follows: 1. DMA completion interrupt occurs and schedules tasklet to call DMA callback. 2. DMA callback for the UART driver starts to execute. This will copy the data from the DMA buffer and restart the DMA. This is done under uart port spinlock. 3. During the callback, UART interrupt is raised for end of receive. The UART ISR runs and waits to acquire port spinlock held by the DMA callback. 4. DMA callback gives up spinlock after copying the data, but before restarting DMA. 5. UART ISR acquires the spin lock and reads the same DMA buffer because DMA has not been restarted yet. The release of the spinlock during the DMA callback was introduced by commit 9b88748b362c ("tty: serial: tegra: drop uart_port->lock before calling tty_flip_buffer_push()") to fix a spinlock lock-up issue when calling tty_flip_buffer_push(). However, since then commit a9c3f68f3cd8 ("tty: Fix low_latency BUG") migrated tty_flip_buffer_push() to always use a workqueue, allowing tty_flip_buffer_push() to be called from within atomic sections. Therefore, we can remove the unlocking of the spinlock from the DMA callback and UART ISR and this will ensure that the race condition no longer occurs. Reported-by: Christopher Freeman <cfreeman@nvidia.com> Signed-off-by: Jon Hunter <jonathanh@nvidia.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2015-10-09 07:49:59 -06:00
tegra_uart_handle_rx_dma(tup);
if (tup->rx_in_progress) {
ier = tup->ier_shadow;
ier |= (UART_IER_RLSI | UART_IER_RTOIE |
TEGRA_UART_IER_EORD);
tup->ier_shadow = ier;
tegra_uart_write(tup, ier, UART_IER);
}
}
spin_unlock_irqrestore(&u->lock, flags);
return IRQ_HANDLED;
}
switch ((iir >> 1) & 0x7) {
case 0: /* Modem signal change interrupt */
tegra_uart_handle_modem_signal_change(u);
break;
case 1: /* Transmit interrupt only triggered when using PIO */
tup->ier_shadow &= ~UART_IER_THRI;
tegra_uart_write(tup, tup->ier_shadow, UART_IER);
tegra_uart_handle_tx_pio(tup);
break;
case 4: /* End of data */
case 6: /* Rx timeout */
case 2: /* Receive */
if (!tup->use_rx_pio && !is_rx_int) {
is_rx_int = true;
/* Disable Rx interrupts */
ier = tup->ier_shadow;
ier |= UART_IER_RDI;
tegra_uart_write(tup, ier, UART_IER);
ier &= ~(UART_IER_RDI | UART_IER_RLSI |
UART_IER_RTOIE | TEGRA_UART_IER_EORD);
tup->ier_shadow = ier;
tegra_uart_write(tup, ier, UART_IER);
} else {
do_handle_rx_pio(tup);
}
break;
case 3: /* Receive error */
tegra_uart_decode_rx_error(tup,
tegra_uart_read(tup, UART_LSR));
break;
case 5: /* break nothing to handle */
case 7: /* break nothing to handle */
break;
}
}
}
static void tegra_uart_stop_rx(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
struct tty_port *port = &tup->uport.state->port;
struct dma_tx_state state;
unsigned long ier;
if (tup->rts_active)
set_rts(tup, false);
if (!tup->rx_in_progress)
return;
tegra_uart_wait_sym_time(tup, 1); /* wait one character interval */
ier = tup->ier_shadow;
ier &= ~(UART_IER_RDI | UART_IER_RLSI | UART_IER_RTOIE |
TEGRA_UART_IER_EORD);
tup->ier_shadow = ier;
tegra_uart_write(tup, ier, UART_IER);
tup->rx_in_progress = 0;
if (tup->rx_dma_chan && !tup->use_rx_pio) {
dmaengine_terminate_all(tup->rx_dma_chan);
dmaengine_tx_status(tup->rx_dma_chan, tup->rx_cookie, &state);
tegra_uart_rx_buffer_push(tup, state.residue);
} else {
tegra_uart_handle_rx_pio(tup, port);
}
}
static void tegra_uart_hw_deinit(struct tegra_uart_port *tup)
{
unsigned long flags;
unsigned long char_time = DIV_ROUND_UP(10000000, tup->current_baud);
unsigned long fifo_empty_time = tup->uport.fifosize * char_time;
unsigned long wait_time;
unsigned long lsr;
unsigned long msr;
unsigned long mcr;
/* Disable interrupts */
tegra_uart_write(tup, 0, UART_IER);
lsr = tegra_uart_read(tup, UART_LSR);
if ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
msr = tegra_uart_read(tup, UART_MSR);
mcr = tegra_uart_read(tup, UART_MCR);
if ((mcr & TEGRA_UART_MCR_CTS_EN) && (msr & UART_MSR_CTS))
dev_err(tup->uport.dev,
"Tx Fifo not empty, CTS disabled, waiting\n");
/* Wait for Tx fifo to be empty */
while ((lsr & UART_LSR_TEMT) != UART_LSR_TEMT) {
wait_time = min(fifo_empty_time, 100lu);
udelay(wait_time);
fifo_empty_time -= wait_time;
if (!fifo_empty_time) {
msr = tegra_uart_read(tup, UART_MSR);
mcr = tegra_uart_read(tup, UART_MCR);
if ((mcr & TEGRA_UART_MCR_CTS_EN) &&
(msr & UART_MSR_CTS))
dev_err(tup->uport.dev,
"Slave not ready\n");
break;
}
lsr = tegra_uart_read(tup, UART_LSR);
}
}
spin_lock_irqsave(&tup->uport.lock, flags);
/* Reset the Rx and Tx FIFOs */
tegra_uart_fifo_reset(tup, UART_FCR_CLEAR_XMIT | UART_FCR_CLEAR_RCVR);
tup->current_baud = 0;
spin_unlock_irqrestore(&tup->uport.lock, flags);
tup->rx_in_progress = 0;
tup->tx_in_progress = 0;
if (!tup->use_rx_pio)
tegra_uart_dma_channel_free(tup, true);
if (!tup->use_tx_pio)
tegra_uart_dma_channel_free(tup, false);
clk_disable_unprepare(tup->uart_clk);
}
static int tegra_uart_hw_init(struct tegra_uart_port *tup)
{
int ret;
tup->fcr_shadow = 0;
tup->mcr_shadow = 0;
tup->lcr_shadow = 0;
tup->ier_shadow = 0;
tup->current_baud = 0;
clk_prepare_enable(tup->uart_clk);
/* Reset the UART controller to clear all previous status.*/
reset_control_assert(tup->rst);
udelay(10);
reset_control_deassert(tup->rst);
tup->rx_in_progress = 0;
tup->tx_in_progress = 0;
/*
* Set the trigger level
*
* For PIO mode:
*
* For receive, this will interrupt the CPU after that many number of
* bytes are received, for the remaining bytes the receive timeout
* interrupt is received. Rx high watermark is set to 4.
*
* For transmit, if the trasnmit interrupt is enabled, this will
* interrupt the CPU when the number of entries in the FIFO reaches the
* low watermark. Tx low watermark is set to 16 bytes.
*
* For DMA mode:
*
* Set the Tx trigger to 16. This should match the DMA burst size that
* programmed in the DMA registers.
*/
tup->fcr_shadow = UART_FCR_ENABLE_FIFO;
if (tup->use_rx_pio) {
tup->fcr_shadow |= UART_FCR_R_TRIG_11;
} else {
if (tup->cdata->max_dma_burst_bytes == 8)
tup->fcr_shadow |= UART_FCR_R_TRIG_10;
else
tup->fcr_shadow |= UART_FCR_R_TRIG_01;
}
tup->fcr_shadow |= TEGRA_UART_TX_TRIG_16B;
tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
/* Dummy read to ensure the write is posted */
tegra_uart_read(tup, UART_SCR);
if (tup->cdata->fifo_mode_enable_status) {
ret = tegra_uart_wait_fifo_mode_enabled(tup);
dev_err(tup->uport.dev, "FIFO mode not enabled\n");
if (ret < 0)
return ret;
} else {
/*
* For all tegra devices (up to t210), there is a hardware
* issue that requires software to wait for 3 UART clock
* periods after enabling the TX fifo, otherwise data could
* be lost.
*/
tegra_uart_wait_cycle_time(tup, 3);
}
/*
* Initialize the UART with default configuration
* (115200, N, 8, 1) so that the receive DMA buffer may be
* enqueued
*/
ret = tegra_set_baudrate(tup, TEGRA_UART_DEFAULT_BAUD);
if (ret < 0) {
dev_err(tup->uport.dev, "Failed to set baud rate\n");
return ret;
}
if (!tup->use_rx_pio) {
tup->lcr_shadow = TEGRA_UART_DEFAULT_LSR;
tup->fcr_shadow |= UART_FCR_DMA_SELECT;
tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
ret = tegra_uart_start_rx_dma(tup);
if (ret < 0) {
dev_err(tup->uport.dev, "Not able to start Rx DMA\n");
return ret;
}
} else {
tegra_uart_write(tup, tup->fcr_shadow, UART_FCR);
}
tup->rx_in_progress = 1;
/*
* Enable IE_RXS for the receive status interrupts like line errros.
* Enable IE_RX_TIMEOUT to get the bytes which cannot be DMA'd.
*
* If using DMA mode, enable EORD instead of receive interrupt which
* will interrupt after the UART is done with the receive instead of
* the interrupt when the FIFO "threshold" is reached.
*
* EORD is different interrupt than RX_TIMEOUT - RX_TIMEOUT occurs when
* the DATA is sitting in the FIFO and couldn't be transferred to the
* DMA as the DMA size alignment (4 bytes) is not met. EORD will be
* triggered when there is a pause of the incomming data stream for 4
* characters long.
*
* For pauses in the data which is not aligned to 4 bytes, we get
* both the EORD as well as RX_TIMEOUT - SW sees RX_TIMEOUT first
* then the EORD.
*/
if (!tup->use_rx_pio)
tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE |
TEGRA_UART_IER_EORD;
else
tup->ier_shadow = UART_IER_RLSI | UART_IER_RTOIE | UART_IER_RDI;
tegra_uart_write(tup, tup->ier_shadow, UART_IER);
return 0;
}
static void tegra_uart_dma_channel_free(struct tegra_uart_port *tup,
bool dma_to_memory)
{
if (dma_to_memory) {
dmaengine_terminate_all(tup->rx_dma_chan);
dma_release_channel(tup->rx_dma_chan);
dma_free_coherent(tup->uport.dev, TEGRA_UART_RX_DMA_BUFFER_SIZE,
tup->rx_dma_buf_virt, tup->rx_dma_buf_phys);
tup->rx_dma_chan = NULL;
tup->rx_dma_buf_phys = 0;
tup->rx_dma_buf_virt = NULL;
} else {
dmaengine_terminate_all(tup->tx_dma_chan);
dma_release_channel(tup->tx_dma_chan);
dma_unmap_single(tup->uport.dev, tup->tx_dma_buf_phys,
UART_XMIT_SIZE, DMA_TO_DEVICE);
tup->tx_dma_chan = NULL;
tup->tx_dma_buf_phys = 0;
tup->tx_dma_buf_virt = NULL;
}
}
static int tegra_uart_dma_channel_allocate(struct tegra_uart_port *tup,
bool dma_to_memory)
{
struct dma_chan *dma_chan;
unsigned char *dma_buf;
dma_addr_t dma_phys;
int ret;
struct dma_slave_config dma_sconfig;
dma_chan = dma_request_slave_channel_reason(tup->uport.dev,
dma_to_memory ? "rx" : "tx");
if (IS_ERR(dma_chan)) {
ret = PTR_ERR(dma_chan);
dev_err(tup->uport.dev,
"DMA channel alloc failed: %d\n", ret);
return ret;
}
if (dma_to_memory) {
dma_buf = dma_alloc_coherent(tup->uport.dev,
TEGRA_UART_RX_DMA_BUFFER_SIZE,
&dma_phys, GFP_KERNEL);
if (!dma_buf) {
dev_err(tup->uport.dev,
"Not able to allocate the dma buffer\n");
dma_release_channel(dma_chan);
return -ENOMEM;
}
dma_sconfig.src_addr = tup->uport.mapbase;
dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
dma_sconfig.src_maxburst = tup->cdata->max_dma_burst_bytes;
tup->rx_dma_chan = dma_chan;
tup->rx_dma_buf_virt = dma_buf;
tup->rx_dma_buf_phys = dma_phys;
} else {
dma_phys = dma_map_single(tup->uport.dev,
tup->uport.state->xmit.buf, UART_XMIT_SIZE,
DMA_TO_DEVICE);
if (dma_mapping_error(tup->uport.dev, dma_phys)) {
dev_err(tup->uport.dev, "dma_map_single tx failed\n");
dma_release_channel(dma_chan);
return -ENOMEM;
}
dma_buf = tup->uport.state->xmit.buf;
dma_sconfig.dst_addr = tup->uport.mapbase;
dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
dma_sconfig.dst_maxburst = 16;
tup->tx_dma_chan = dma_chan;
tup->tx_dma_buf_virt = dma_buf;
tup->tx_dma_buf_phys = dma_phys;
}
ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
if (ret < 0) {
dev_err(tup->uport.dev,
"Dma slave config failed, err = %d\n", ret);
tegra_uart_dma_channel_free(tup, dma_to_memory);
return ret;
}
return 0;
}
static int tegra_uart_startup(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
int ret;
if (!tup->use_tx_pio) {
ret = tegra_uart_dma_channel_allocate(tup, false);
if (ret < 0) {
dev_err(u->dev, "Tx Dma allocation failed, err = %d\n",
ret);
return ret;
}
}
if (!tup->use_rx_pio) {
ret = tegra_uart_dma_channel_allocate(tup, true);
if (ret < 0) {
dev_err(u->dev, "Rx Dma allocation failed, err = %d\n",
ret);
goto fail_rx_dma;
}
}
ret = tegra_uart_hw_init(tup);
if (ret < 0) {
dev_err(u->dev, "Uart HW init failed, err = %d\n", ret);
goto fail_hw_init;
}
ret = request_irq(u->irq, tegra_uart_isr, 0,
dev_name(u->dev), tup);
if (ret < 0) {
dev_err(u->dev, "Failed to register ISR for IRQ %d\n", u->irq);
goto fail_hw_init;
}
return 0;
fail_hw_init:
if (!tup->use_rx_pio)
tegra_uart_dma_channel_free(tup, true);
fail_rx_dma:
if (!tup->use_tx_pio)
tegra_uart_dma_channel_free(tup, false);
return ret;
}
/*
* Flush any TX data submitted for DMA and PIO. Called when the
* TX circular buffer is reset.
*/
static void tegra_uart_flush_buffer(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
tup->tx_bytes = 0;
if (tup->tx_dma_chan)
dmaengine_terminate_all(tup->tx_dma_chan);
}
static void tegra_uart_shutdown(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
tegra_uart_hw_deinit(tup);
free_irq(u->irq, tup);
}
static void tegra_uart_enable_ms(struct uart_port *u)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
if (tup->enable_modem_interrupt) {
tup->ier_shadow |= UART_IER_MSI;
tegra_uart_write(tup, tup->ier_shadow, UART_IER);
}
}
static void tegra_uart_set_termios(struct uart_port *u,
struct ktermios *termios, struct ktermios *oldtermios)
{
struct tegra_uart_port *tup = to_tegra_uport(u);
unsigned int baud;
unsigned long flags;
unsigned int lcr;
int symb_bit = 1;
struct clk *parent_clk = clk_get_parent(tup->uart_clk);
unsigned long parent_clk_rate = clk_get_rate(parent_clk);
int max_divider = (tup->cdata->support_clk_src_div) ? 0x7FFF : 0xFFFF;
int ret;
max_divider *= 16;
spin_lock_irqsave(&u->lock, flags);
/* Changing configuration, it is safe to stop any rx now */
if (tup->rts_active)
set_rts(tup, false);
/* Clear all interrupts as configuration is going to be changed */
tegra_uart_write(tup, tup->ier_shadow | UART_IER_RDI, UART_IER);
tegra_uart_read(tup, UART_IER);
tegra_uart_write(tup, 0, UART_IER);
tegra_uart_read(tup, UART_IER);
/* Parity */
lcr = tup->lcr_shadow;
lcr &= ~UART_LCR_PARITY;
/* CMSPAR isn't supported by this driver */
termios->c_cflag &= ~CMSPAR;
if ((termios->c_cflag & PARENB) == PARENB) {
symb_bit++;
if (termios->c_cflag & PARODD) {
lcr |= UART_LCR_PARITY;
lcr &= ~UART_LCR_EPAR;
lcr &= ~UART_LCR_SPAR;
} else {
lcr |= UART_LCR_PARITY;
lcr |= UART_LCR_EPAR;
lcr &= ~UART_LCR_SPAR;
}
}
lcr &= ~UART_LCR_WLEN8;
switch (termios->c_cflag & CSIZE) {
case CS5:
lcr |= UART_LCR_WLEN5;
symb_bit += 5;
break;
case CS6:
lcr |= UART_LCR_WLEN6;
symb_bit += 6;
break;
case CS7:
lcr |= UART_LCR_WLEN7;
symb_bit += 7;
break;
default:
lcr |= UART_LCR_WLEN8;
symb_bit += 8;
break;
}
/* Stop bits */
if (termios->c_cflag & CSTOPB) {
lcr |= UART_LCR_STOP;
symb_bit += 2;
} else {
lcr &= ~UART_LCR_STOP;
symb_bit++;
}
tegra_uart_write(tup, lcr, UART_LCR);
tup->lcr_shadow = lcr;
tup->symb_bit = symb_bit;
/* Baud rate. */
baud = uart_get_baud_rate(u, termios, oldtermios,
parent_clk_rate/max_divider,
parent_clk_rate/16);
spin_unlock_irqrestore(&u->lock, flags);
ret = tegra_set_baudrate(tup, baud);
if (ret < 0) {
dev_err(tup->uport.dev, "Failed to set baud rate\n");
return;
}
if (tty_termios_baud_rate(termios))
tty_termios_encode_baud_rate(termios, baud, baud);
spin_lock_irqsave(&u->lock, flags);
/* Flow control */
if (termios->c_cflag & CRTSCTS) {
tup->mcr_shadow |= TEGRA_UART_MCR_CTS_EN;
tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
/* if top layer has asked to set rts active then do so here */
if (tup->rts_active)
set_rts(tup, true);
} else {
tup->mcr_shadow &= ~TEGRA_UART_MCR_CTS_EN;
tup->mcr_shadow &= ~TEGRA_UART_MCR_RTS_EN;
tegra_uart_write(tup, tup->mcr_shadow, UART_MCR);
}
/* update the port timeout based on new settings */
uart_update_timeout(u, termios->c_cflag, baud);
/* Make sure all writes have completed */
tegra_uart_read(tup, UART_IER);
/* Re-enable interrupt */
tegra_uart_write(tup, tup->ier_shadow, UART_IER);
tegra_uart_read(tup, UART_IER);
tup->uport.ignore_status_mask = 0;
/* Ignore all characters if CREAD is not set */
if ((termios->c_cflag & CREAD) == 0)
tup->uport.ignore_status_mask |= UART_LSR_DR;
if (termios->c_iflag & IGNBRK)
tup->uport.ignore_status_mask |= UART_LSR_BI;
spin_unlock_irqrestore(&u->lock, flags);
}
static const char *tegra_uart_type(struct uart_port *u)
{
return TEGRA_UART_TYPE;
}
tty: serial: constify uart_ops structures Declare uart_ops structures as const as they are only stored in the ops field of an uart_port structure. This field is of type const, so uart_ops structures having this property can be made const too. File size details before and after patching. First line of every .o file shows the file size before patching and second line shows the size after patching. text data bss dec hex filename 2977 456 64 3497 da9 drivers/tty/serial/amba-pl010.o 3169 272 64 3505 db1 drivers/tty/serial/amba-pl010.o 3109 456 0 3565 ded drivers/tty/serial/efm32-uart.o 3301 272 0 3573 df5 drivers/tty/serial/efm32-uart.o 10668 753 1 11422 2c9e drivers/tty/serial/icom.o 10860 561 1 11422 2c9e drivers/tty/serial/icom.o 23904 408 8 24320 5f00 drivers/tty/serial/ioc3_serial.o 24088 224 8 24320 5f00 drivers/tty/serial/ioc3_serial.o 10516 560 4 11080 2b48 drivers/tty/serial/ioc4_serial.o 10709 368 4 11081 2b49 drivers/tty/serial/ioc4_serial.o 7853 648 1216 9717 25f5 drivers/tty/serial/mpsc.o 8037 456 1216 9709 25ed drivers/tty/serial/mpsc.o 10248 456 0 10704 29d0 drivers/tty/serial/omap-serial.o 10440 272 0 10712 29d8 drivers/tty/serial/omap-serial.o 8122 532 1984 10638 298e drivers/tty/serial/pmac_zilog.o 8306 340 1984 10630 2986 drivers/tty/serial/pmac_zilog.o 3808 456 0 4264 10a8 drivers/tty/serial/pxa.o 4000 264 0 4264 10a8 drivers/tty/serial/pxa.o 21781 3864 0 25645 642d drivers/tty/serial/serial-tegra.o 22037 3608 0 25645 642d drivers/tty/serial/serial-tegra.o 2481 456 96 3033 bd9 drivers/tty/serial/sprd_serial.o 2673 272 96 3041 be1 drivers/tty/serial/sprd_serial.o 5534 300 512 6346 18ca drivers/tty/serial/vr41xx_siu.o 5630 204 512 6346 18ca drivers/tty/serial/vr41xx_siu.o 6730 1576 128 8434 20f2 drivers/tty/serial/vt8500_serial.o 6986 1320 128 8434 20f2 drivers/tty/serial/vt8500_serial.o Cross compiled for mips architecture. 3005 488 0 3493 da5 drivers/tty/serial/pnx8xxx_uart.o 3189 304 0 3493 da5 drivers/tty/serial/pnx8xxx_uart.o 4272 196 1056 5524 1594 drivers/tty/serial/dz.o 4368 100 1056 5524 1594 drivers/tty/serial/dz.o 6551 144 16 6711 1a37 drivers/tty/serial/ip22zilog.o 6647 48 16 6711 1a37 drivers/tty/serial/ip22zilog.o 9612 428 1520 11560 2d28 drivers/tty/serial/serial_txx9.o 9708 332 1520 11560 2d28 drivers/tty/serial/serial_txx9.o 4156 296 16 4468 1174 drivers/tty/serial/ar933x_uart.o 4252 200 16 4468 1174 drivers/tty/serial/ar933x_uart.o Cross compiled for arm archiecture. 11716 1780 44 13540 34e4 drivers/tty/serial/sirfsoc_uart.o 11808 1688 44 13540 34e4 drivers/tty/serial/sirfsoc_uart.o 13352 596 56 14004 36b4 drivers/tty/serial/amba-pl011.o 13444 504 56 14004 36b4 drivers/tty/serial/amba-pl011.o Cross compiled for sparc architecture. 4664 528 32 5224 1468 drivers/tty/serial/sunhv.o 4848 344 32 5224 1468 drivers/tty/serial/sunhv.o 8080 332 28 8440 20f8 drivers/tty/serial/sunzilog.o 8184 228 28 8440 20f8 drivers/tty/serial/sunzilog.o Cross compiled for ia64 architecture. 10226 549 472 11247 2bef drivers/tty/serial/sn_console.o 10414 365 472 11251 2bf3 drivers/tty/serial/sn_console.o The files drivers/tty/serial/zs.o, drivers/tty/serial/lpc32xx_hs.o and drivers/tty/serial/lantiq.o did not compile. Signed-off-by: Bhumika Goyal <bhumirks@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-25 10:48:52 -07:00
static const struct uart_ops tegra_uart_ops = {
.tx_empty = tegra_uart_tx_empty,
.set_mctrl = tegra_uart_set_mctrl,
.get_mctrl = tegra_uart_get_mctrl,
.stop_tx = tegra_uart_stop_tx,
.start_tx = tegra_uart_start_tx,
.stop_rx = tegra_uart_stop_rx,
.flush_buffer = tegra_uart_flush_buffer,
.enable_ms = tegra_uart_enable_ms,
.break_ctl = tegra_uart_break_ctl,
.startup = tegra_uart_startup,
.shutdown = tegra_uart_shutdown,
.set_termios = tegra_uart_set_termios,
.type = tegra_uart_type,
.request_port = tegra_uart_request_port,
.release_port = tegra_uart_release_port,
};
static struct uart_driver tegra_uart_driver = {
.owner = THIS_MODULE,
.driver_name = "tegra_hsuart",
.dev_name = "ttyTHS",
.cons = NULL,
.nr = TEGRA_UART_MAXIMUM,
};
static int tegra_uart_parse_dt(struct platform_device *pdev,
struct tegra_uart_port *tup)
{
struct device_node *np = pdev->dev.of_node;
int port;
int ret;
int index;
u32 pval;
int count;
int n_entries;
port = of_alias_get_id(np, "serial");
if (port < 0) {
dev_err(&pdev->dev, "failed to get alias id, errno %d\n", port);
return port;
}
tup->uport.line = port;
tup->enable_modem_interrupt = of_property_read_bool(np,
"nvidia,enable-modem-interrupt");
index = of_property_match_string(np, "dma-names", "rx");
if (index < 0) {
tup->use_rx_pio = true;
dev_info(&pdev->dev, "RX in PIO mode\n");
}
index = of_property_match_string(np, "dma-names", "tx");
if (index < 0) {
tup->use_tx_pio = true;
dev_info(&pdev->dev, "TX in PIO mode\n");
}
n_entries = of_property_count_u32_elems(np, "nvidia,adjust-baud-rates");
if (n_entries > 0) {
tup->n_adjustable_baud_rates = n_entries / 3;
tup->baud_tolerance =
devm_kzalloc(&pdev->dev, (tup->n_adjustable_baud_rates) *
sizeof(*tup->baud_tolerance), GFP_KERNEL);
if (!tup->baud_tolerance)
return -ENOMEM;
for (count = 0, index = 0; count < n_entries; count += 3,
index++) {
ret =
of_property_read_u32_index(np,
"nvidia,adjust-baud-rates",
count, &pval);
if (!ret)
tup->baud_tolerance[index].lower_range_baud =
pval;
ret =
of_property_read_u32_index(np,
"nvidia,adjust-baud-rates",
count + 1, &pval);
if (!ret)
tup->baud_tolerance[index].upper_range_baud =
pval;
ret =
of_property_read_u32_index(np,
"nvidia,adjust-baud-rates",
count + 2, &pval);
if (!ret)
tup->baud_tolerance[index].tolerance =
(s32)pval;
}
} else {
tup->n_adjustable_baud_rates = 0;
}
return 0;
}
static struct tegra_uart_chip_data tegra20_uart_chip_data = {
.tx_fifo_full_status = false,
.allow_txfifo_reset_fifo_mode = true,
.support_clk_src_div = false,
.fifo_mode_enable_status = false,
.uart_max_port = 5,
.max_dma_burst_bytes = 4,
.error_tolerance_low_range = 0,
.error_tolerance_high_range = 4,
};
static struct tegra_uart_chip_data tegra30_uart_chip_data = {
.tx_fifo_full_status = true,
.allow_txfifo_reset_fifo_mode = false,
.support_clk_src_div = true,
.fifo_mode_enable_status = false,
.uart_max_port = 5,
.max_dma_burst_bytes = 4,
.error_tolerance_low_range = 0,
.error_tolerance_high_range = 4,
};
static struct tegra_uart_chip_data tegra186_uart_chip_data = {
.tx_fifo_full_status = true,
.allow_txfifo_reset_fifo_mode = false,
.support_clk_src_div = true,
.fifo_mode_enable_status = true,
.uart_max_port = 8,
.max_dma_burst_bytes = 8,
.error_tolerance_low_range = 0,
.error_tolerance_high_range = 4,
};
static struct tegra_uart_chip_data tegra194_uart_chip_data = {
.tx_fifo_full_status = true,
.allow_txfifo_reset_fifo_mode = false,
.support_clk_src_div = true,
.fifo_mode_enable_status = true,
.uart_max_port = 8,
.max_dma_burst_bytes = 8,
.error_tolerance_low_range = -2,
.error_tolerance_high_range = 2,
};
static const struct of_device_id tegra_uart_of_match[] = {
{
.compatible = "nvidia,tegra30-hsuart",
.data = &tegra30_uart_chip_data,
}, {
.compatible = "nvidia,tegra20-hsuart",
.data = &tegra20_uart_chip_data,
}, {
.compatible = "nvidia,tegra186-hsuart",
.data = &tegra186_uart_chip_data,
}, {
.compatible = "nvidia,tegra194-hsuart",
.data = &tegra194_uart_chip_data,
}, {
},
};
MODULE_DEVICE_TABLE(of, tegra_uart_of_match);
static int tegra_uart_probe(struct platform_device *pdev)
{
struct tegra_uart_port *tup;
struct uart_port *u;
struct resource *resource;
int ret;
const struct tegra_uart_chip_data *cdata;
const struct of_device_id *match;
match = of_match_device(tegra_uart_of_match, &pdev->dev);
if (!match) {
dev_err(&pdev->dev, "Error: No device match found\n");
return -ENODEV;
}
cdata = match->data;
tup = devm_kzalloc(&pdev->dev, sizeof(*tup), GFP_KERNEL);
if (!tup) {
dev_err(&pdev->dev, "Failed to allocate memory for tup\n");
return -ENOMEM;
}
ret = tegra_uart_parse_dt(pdev, tup);
if (ret < 0)
return ret;
u = &tup->uport;
u->dev = &pdev->dev;
u->ops = &tegra_uart_ops;
u->type = PORT_TEGRA;
u->fifosize = 32;
tup->cdata = cdata;
platform_set_drvdata(pdev, tup);
resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!resource) {
dev_err(&pdev->dev, "No IO memory resource\n");
return -ENODEV;
}
u->mapbase = resource->start;
u->membase = devm_ioremap_resource(&pdev->dev, resource);
if (IS_ERR(u->membase))
return PTR_ERR(u->membase);
tup->uart_clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(tup->uart_clk)) {
dev_err(&pdev->dev, "Couldn't get the clock\n");
return PTR_ERR(tup->uart_clk);
}
tup->rst = devm_reset_control_get_exclusive(&pdev->dev, "serial");
if (IS_ERR(tup->rst)) {
dev_err(&pdev->dev, "Couldn't get the reset\n");
return PTR_ERR(tup->rst);
}
u->iotype = UPIO_MEM32;
ret = platform_get_irq(pdev, 0);
if (ret < 0)
return ret;
u->irq = ret;
u->regshift = 2;
ret = uart_add_one_port(&tegra_uart_driver, u);
if (ret < 0) {
dev_err(&pdev->dev, "Failed to add uart port, err %d\n", ret);
return ret;
}
return ret;
}
static int tegra_uart_remove(struct platform_device *pdev)
{
struct tegra_uart_port *tup = platform_get_drvdata(pdev);
struct uart_port *u = &tup->uport;
uart_remove_one_port(&tegra_uart_driver, u);
return 0;
}
#ifdef CONFIG_PM_SLEEP
static int tegra_uart_suspend(struct device *dev)
{
struct tegra_uart_port *tup = dev_get_drvdata(dev);
struct uart_port *u = &tup->uport;
return uart_suspend_port(&tegra_uart_driver, u);
}
static int tegra_uart_resume(struct device *dev)
{
struct tegra_uart_port *tup = dev_get_drvdata(dev);
struct uart_port *u = &tup->uport;
return uart_resume_port(&tegra_uart_driver, u);
}
#endif
static const struct dev_pm_ops tegra_uart_pm_ops = {
SET_SYSTEM_SLEEP_PM_OPS(tegra_uart_suspend, tegra_uart_resume)
};
static struct platform_driver tegra_uart_platform_driver = {
.probe = tegra_uart_probe,
.remove = tegra_uart_remove,
.driver = {
.name = "serial-tegra",
.of_match_table = tegra_uart_of_match,
.pm = &tegra_uart_pm_ops,
},
};
static int __init tegra_uart_init(void)
{
int ret;
struct device_node *node;
const struct of_device_id *match = NULL;
const struct tegra_uart_chip_data *cdata = NULL;
node = of_find_matching_node(NULL, tegra_uart_of_match);
if (node)
match = of_match_node(tegra_uart_of_match, node);
if (match)
cdata = match->data;
if (cdata)
tegra_uart_driver.nr = cdata->uart_max_port;
ret = uart_register_driver(&tegra_uart_driver);
if (ret < 0) {
pr_err("Could not register %s driver\n",
tegra_uart_driver.driver_name);
return ret;
}
ret = platform_driver_register(&tegra_uart_platform_driver);
if (ret < 0) {
pr_err("Uart platform driver register failed, e = %d\n", ret);
uart_unregister_driver(&tegra_uart_driver);
return ret;
}
return 0;
}
static void __exit tegra_uart_exit(void)
{
pr_info("Unloading tegra uart driver\n");
platform_driver_unregister(&tegra_uart_platform_driver);
uart_unregister_driver(&tegra_uart_driver);
}
module_init(tegra_uart_init);
module_exit(tegra_uart_exit);
MODULE_ALIAS("platform:serial-tegra");
MODULE_DESCRIPTION("High speed UART driver for tegra chipset");
MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
MODULE_LICENSE("GPL v2");