remarkable-linux/drivers/tty/serial/amba-pl011.c
Anton Vorontsov 5c8124a0f8 tty/serial/amba-pl011: Quiesce interrupts in poll_get_char
We need to quiesce interrupts in the poll_get_char routine, otherwise,
if used with KGDB NMI debugger, we'll keep reentering the NMI.

Quiescing interrupts is pretty straightforward, except for TXIM
interrupt. The interrupt has "ready to transmit" meaning, so it's
almost always raised, and the only way to silence it is to mask it. But
that's OK, ops->start_tx will unmask it.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-09-26 13:51:32 -07:00

2152 lines
54 KiB
C

/*
* Driver for AMBA serial ports
*
* Based on drivers/char/serial.c, by Linus Torvalds, Theodore Ts'o.
*
* Copyright 1999 ARM Limited
* Copyright (C) 2000 Deep Blue Solutions Ltd.
* Copyright (C) 2010 ST-Ericsson SA
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*
* This is a generic driver for ARM AMBA-type serial ports. They
* have a lot of 16550-like features, but are not register compatible.
* Note that although they do have CTS, DCD and DSR inputs, they do
* not have an RI input, nor do they have DTR or RTS outputs. If
* required, these have to be supplied via some other means (eg, GPIO)
* and hooked into this driver.
*/
#if defined(CONFIG_SERIAL_AMBA_PL011_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ)
#define SUPPORT_SYSRQ
#endif
#include <linux/module.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/console.h>
#include <linux/sysrq.h>
#include <linux/device.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
#include <linux/serial_core.h>
#include <linux/serial.h>
#include <linux/amba/bus.h>
#include <linux/amba/serial.h>
#include <linux/clk.h>
#include <linux/slab.h>
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/scatterlist.h>
#include <linux/delay.h>
#include <linux/types.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/pinctrl/consumer.h>
#include <linux/sizes.h>
#include <asm/io.h>
#define UART_NR 14
#define SERIAL_AMBA_MAJOR 204
#define SERIAL_AMBA_MINOR 64
#define SERIAL_AMBA_NR UART_NR
#define AMBA_ISR_PASS_LIMIT 256
#define UART_DR_ERROR (UART011_DR_OE|UART011_DR_BE|UART011_DR_PE|UART011_DR_FE)
#define UART_DUMMY_DR_RX (1 << 16)
/* There is by now at least one vendor with differing details, so handle it */
struct vendor_data {
unsigned int ifls;
unsigned int fifosize;
unsigned int lcrh_tx;
unsigned int lcrh_rx;
bool oversampling;
bool dma_threshold;
bool cts_event_workaround;
};
static struct vendor_data vendor_arm = {
.ifls = UART011_IFLS_RX4_8|UART011_IFLS_TX4_8,
.fifosize = 16,
.lcrh_tx = UART011_LCRH,
.lcrh_rx = UART011_LCRH,
.oversampling = false,
.dma_threshold = false,
.cts_event_workaround = false,
};
static struct vendor_data vendor_st = {
.ifls = UART011_IFLS_RX_HALF|UART011_IFLS_TX_HALF,
.fifosize = 64,
.lcrh_tx = ST_UART011_LCRH_TX,
.lcrh_rx = ST_UART011_LCRH_RX,
.oversampling = true,
.dma_threshold = true,
.cts_event_workaround = true,
};
static struct uart_amba_port *amba_ports[UART_NR];
/* Deals with DMA transactions */
struct pl011_sgbuf {
struct scatterlist sg;
char *buf;
};
struct pl011_dmarx_data {
struct dma_chan *chan;
struct completion complete;
bool use_buf_b;
struct pl011_sgbuf sgbuf_a;
struct pl011_sgbuf sgbuf_b;
dma_cookie_t cookie;
bool running;
};
struct pl011_dmatx_data {
struct dma_chan *chan;
struct scatterlist sg;
char *buf;
bool queued;
};
/*
* We wrap our port structure around the generic uart_port.
*/
struct uart_amba_port {
struct uart_port port;
struct clk *clk;
/* Two optional pin states - default & sleep */
struct pinctrl *pinctrl;
struct pinctrl_state *pins_default;
struct pinctrl_state *pins_sleep;
const struct vendor_data *vendor;
unsigned int dmacr; /* dma control reg */
unsigned int im; /* interrupt mask */
unsigned int old_status;
unsigned int fifosize; /* vendor-specific */
unsigned int lcrh_tx; /* vendor-specific */
unsigned int lcrh_rx; /* vendor-specific */
unsigned int old_cr; /* state during shutdown */
bool autorts;
char type[12];
#ifdef CONFIG_DMA_ENGINE
/* DMA stuff */
bool using_tx_dma;
bool using_rx_dma;
struct pl011_dmarx_data dmarx;
struct pl011_dmatx_data dmatx;
#endif
};
/*
* Reads up to 256 characters from the FIFO or until it's empty and
* inserts them into the TTY layer. Returns the number of characters
* read from the FIFO.
*/
static int pl011_fifo_to_tty(struct uart_amba_port *uap)
{
u16 status, ch;
unsigned int flag, max_count = 256;
int fifotaken = 0;
while (max_count--) {
status = readw(uap->port.membase + UART01x_FR);
if (status & UART01x_FR_RXFE)
break;
/* Take chars from the FIFO and update status */
ch = readw(uap->port.membase + UART01x_DR) |
UART_DUMMY_DR_RX;
flag = TTY_NORMAL;
uap->port.icount.rx++;
fifotaken++;
if (unlikely(ch & UART_DR_ERROR)) {
if (ch & UART011_DR_BE) {
ch &= ~(UART011_DR_FE | UART011_DR_PE);
uap->port.icount.brk++;
if (uart_handle_break(&uap->port))
continue;
} else if (ch & UART011_DR_PE)
uap->port.icount.parity++;
else if (ch & UART011_DR_FE)
uap->port.icount.frame++;
if (ch & UART011_DR_OE)
uap->port.icount.overrun++;
ch &= uap->port.read_status_mask;
if (ch & UART011_DR_BE)
flag = TTY_BREAK;
else if (ch & UART011_DR_PE)
flag = TTY_PARITY;
else if (ch & UART011_DR_FE)
flag = TTY_FRAME;
}
if (uart_handle_sysrq_char(&uap->port, ch & 255))
continue;
uart_insert_char(&uap->port, ch, UART011_DR_OE, ch, flag);
}
return fifotaken;
}
/*
* All the DMA operation mode stuff goes inside this ifdef.
* This assumes that you have a generic DMA device interface,
* no custom DMA interfaces are supported.
*/
#ifdef CONFIG_DMA_ENGINE
#define PL011_DMA_BUFFER_SIZE PAGE_SIZE
static int pl011_sgbuf_init(struct dma_chan *chan, struct pl011_sgbuf *sg,
enum dma_data_direction dir)
{
sg->buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL);
if (!sg->buf)
return -ENOMEM;
sg_init_one(&sg->sg, sg->buf, PL011_DMA_BUFFER_SIZE);
if (dma_map_sg(chan->device->dev, &sg->sg, 1, dir) != 1) {
kfree(sg->buf);
return -EINVAL;
}
return 0;
}
static void pl011_sgbuf_free(struct dma_chan *chan, struct pl011_sgbuf *sg,
enum dma_data_direction dir)
{
if (sg->buf) {
dma_unmap_sg(chan->device->dev, &sg->sg, 1, dir);
kfree(sg->buf);
}
}
static void pl011_dma_probe_initcall(struct uart_amba_port *uap)
{
/* DMA is the sole user of the platform data right now */
struct amba_pl011_data *plat = uap->port.dev->platform_data;
struct dma_slave_config tx_conf = {
.dst_addr = uap->port.mapbase + UART01x_DR,
.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
.direction = DMA_MEM_TO_DEV,
.dst_maxburst = uap->fifosize >> 1,
.device_fc = false,
};
struct dma_chan *chan;
dma_cap_mask_t mask;
/* We need platform data */
if (!plat || !plat->dma_filter) {
dev_info(uap->port.dev, "no DMA platform data\n");
return;
}
/* Try to acquire a generic DMA engine slave TX channel */
dma_cap_zero(mask);
dma_cap_set(DMA_SLAVE, mask);
chan = dma_request_channel(mask, plat->dma_filter, plat->dma_tx_param);
if (!chan) {
dev_err(uap->port.dev, "no TX DMA channel!\n");
return;
}
dmaengine_slave_config(chan, &tx_conf);
uap->dmatx.chan = chan;
dev_info(uap->port.dev, "DMA channel TX %s\n",
dma_chan_name(uap->dmatx.chan));
/* Optionally make use of an RX channel as well */
if (plat->dma_rx_param) {
struct dma_slave_config rx_conf = {
.src_addr = uap->port.mapbase + UART01x_DR,
.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE,
.direction = DMA_DEV_TO_MEM,
.src_maxburst = uap->fifosize >> 1,
.device_fc = false,
};
chan = dma_request_channel(mask, plat->dma_filter, plat->dma_rx_param);
if (!chan) {
dev_err(uap->port.dev, "no RX DMA channel!\n");
return;
}
dmaengine_slave_config(chan, &rx_conf);
uap->dmarx.chan = chan;
dev_info(uap->port.dev, "DMA channel RX %s\n",
dma_chan_name(uap->dmarx.chan));
}
}
#ifndef MODULE
/*
* Stack up the UARTs and let the above initcall be done at device
* initcall time, because the serial driver is called as an arch
* initcall, and at this time the DMA subsystem is not yet registered.
* At this point the driver will switch over to using DMA where desired.
*/
struct dma_uap {
struct list_head node;
struct uart_amba_port *uap;
};
static LIST_HEAD(pl011_dma_uarts);
static int __init pl011_dma_initcall(void)
{
struct list_head *node, *tmp;
list_for_each_safe(node, tmp, &pl011_dma_uarts) {
struct dma_uap *dmau = list_entry(node, struct dma_uap, node);
pl011_dma_probe_initcall(dmau->uap);
list_del(node);
kfree(dmau);
}
return 0;
}
device_initcall(pl011_dma_initcall);
static void pl011_dma_probe(struct uart_amba_port *uap)
{
struct dma_uap *dmau = kzalloc(sizeof(struct dma_uap), GFP_KERNEL);
if (dmau) {
dmau->uap = uap;
list_add_tail(&dmau->node, &pl011_dma_uarts);
}
}
#else
static void pl011_dma_probe(struct uart_amba_port *uap)
{
pl011_dma_probe_initcall(uap);
}
#endif
static void pl011_dma_remove(struct uart_amba_port *uap)
{
/* TODO: remove the initcall if it has not yet executed */
if (uap->dmatx.chan)
dma_release_channel(uap->dmatx.chan);
if (uap->dmarx.chan)
dma_release_channel(uap->dmarx.chan);
}
/* Forward declare this for the refill routine */
static int pl011_dma_tx_refill(struct uart_amba_port *uap);
/*
* The current DMA TX buffer has been sent.
* Try to queue up another DMA buffer.
*/
static void pl011_dma_tx_callback(void *data)
{
struct uart_amba_port *uap = data;
struct pl011_dmatx_data *dmatx = &uap->dmatx;
unsigned long flags;
u16 dmacr;
spin_lock_irqsave(&uap->port.lock, flags);
if (uap->dmatx.queued)
dma_unmap_sg(dmatx->chan->device->dev, &dmatx->sg, 1,
DMA_TO_DEVICE);
dmacr = uap->dmacr;
uap->dmacr = dmacr & ~UART011_TXDMAE;
writew(uap->dmacr, uap->port.membase + UART011_DMACR);
/*
* If TX DMA was disabled, it means that we've stopped the DMA for
* some reason (eg, XOFF received, or we want to send an X-char.)
*
* Note: we need to be careful here of a potential race between DMA
* and the rest of the driver - if the driver disables TX DMA while
* a TX buffer completing, we must update the tx queued status to
* get further refills (hence we check dmacr).
*/
if (!(dmacr & UART011_TXDMAE) || uart_tx_stopped(&uap->port) ||
uart_circ_empty(&uap->port.state->xmit)) {
uap->dmatx.queued = false;
spin_unlock_irqrestore(&uap->port.lock, flags);
return;
}
if (pl011_dma_tx_refill(uap) <= 0) {
/*
* We didn't queue a DMA buffer for some reason, but we
* have data pending to be sent. Re-enable the TX IRQ.
*/
uap->im |= UART011_TXIM;
writew(uap->im, uap->port.membase + UART011_IMSC);
}
spin_unlock_irqrestore(&uap->port.lock, flags);
}
/*
* Try to refill the TX DMA buffer.
* Locking: called with port lock held and IRQs disabled.
* Returns:
* 1 if we queued up a TX DMA buffer.
* 0 if we didn't want to handle this by DMA
* <0 on error
*/
static int pl011_dma_tx_refill(struct uart_amba_port *uap)
{
struct pl011_dmatx_data *dmatx = &uap->dmatx;
struct dma_chan *chan = dmatx->chan;
struct dma_device *dma_dev = chan->device;
struct dma_async_tx_descriptor *desc;
struct circ_buf *xmit = &uap->port.state->xmit;
unsigned int count;
/*
* Try to avoid the overhead involved in using DMA if the
* transaction fits in the first half of the FIFO, by using
* the standard interrupt handling. This ensures that we
* issue a uart_write_wakeup() at the appropriate time.
*/
count = uart_circ_chars_pending(xmit);
if (count < (uap->fifosize >> 1)) {
uap->dmatx.queued = false;
return 0;
}
/*
* Bodge: don't send the last character by DMA, as this
* will prevent XON from notifying us to restart DMA.
*/
count -= 1;
/* Else proceed to copy the TX chars to the DMA buffer and fire DMA */
if (count > PL011_DMA_BUFFER_SIZE)
count = PL011_DMA_BUFFER_SIZE;
if (xmit->tail < xmit->head)
memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], count);
else {
size_t first = UART_XMIT_SIZE - xmit->tail;
size_t second = xmit->head;
memcpy(&dmatx->buf[0], &xmit->buf[xmit->tail], first);
if (second)
memcpy(&dmatx->buf[first], &xmit->buf[0], second);
}
dmatx->sg.length = count;
if (dma_map_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE) != 1) {
uap->dmatx.queued = false;
dev_dbg(uap->port.dev, "unable to map TX DMA\n");
return -EBUSY;
}
desc = dmaengine_prep_slave_sg(chan, &dmatx->sg, 1, DMA_MEM_TO_DEV,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
if (!desc) {
dma_unmap_sg(dma_dev->dev, &dmatx->sg, 1, DMA_TO_DEVICE);
uap->dmatx.queued = false;
/*
* If DMA cannot be used right now, we complete this
* transaction via IRQ and let the TTY layer retry.
*/
dev_dbg(uap->port.dev, "TX DMA busy\n");
return -EBUSY;
}
/* Some data to go along to the callback */
desc->callback = pl011_dma_tx_callback;
desc->callback_param = uap;
/* All errors should happen at prepare time */
dmaengine_submit(desc);
/* Fire the DMA transaction */
dma_dev->device_issue_pending(chan);
uap->dmacr |= UART011_TXDMAE;
writew(uap->dmacr, uap->port.membase + UART011_DMACR);
uap->dmatx.queued = true;
/*
* Now we know that DMA will fire, so advance the ring buffer
* with the stuff we just dispatched.
*/
xmit->tail = (xmit->tail + count) & (UART_XMIT_SIZE - 1);
uap->port.icount.tx += count;
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&uap->port);
return 1;
}
/*
* We received a transmit interrupt without a pending X-char but with
* pending characters.
* Locking: called with port lock held and IRQs disabled.
* Returns:
* false if we want to use PIO to transmit
* true if we queued a DMA buffer
*/
static bool pl011_dma_tx_irq(struct uart_amba_port *uap)
{
if (!uap->using_tx_dma)
return false;
/*
* If we already have a TX buffer queued, but received a
* TX interrupt, it will be because we've just sent an X-char.
* Ensure the TX DMA is enabled and the TX IRQ is disabled.
*/
if (uap->dmatx.queued) {
uap->dmacr |= UART011_TXDMAE;
writew(uap->dmacr, uap->port.membase + UART011_DMACR);
uap->im &= ~UART011_TXIM;
writew(uap->im, uap->port.membase + UART011_IMSC);
return true;
}
/*
* We don't have a TX buffer queued, so try to queue one.
* If we successfully queued a buffer, mask the TX IRQ.
*/
if (pl011_dma_tx_refill(uap) > 0) {
uap->im &= ~UART011_TXIM;
writew(uap->im, uap->port.membase + UART011_IMSC);
return true;
}
return false;
}
/*
* Stop the DMA transmit (eg, due to received XOFF).
* Locking: called with port lock held and IRQs disabled.
*/
static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
{
if (uap->dmatx.queued) {
uap->dmacr &= ~UART011_TXDMAE;
writew(uap->dmacr, uap->port.membase + UART011_DMACR);
}
}
/*
* Try to start a DMA transmit, or in the case of an XON/OFF
* character queued for send, try to get that character out ASAP.
* Locking: called with port lock held and IRQs disabled.
* Returns:
* false if we want the TX IRQ to be enabled
* true if we have a buffer queued
*/
static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
{
u16 dmacr;
if (!uap->using_tx_dma)
return false;
if (!uap->port.x_char) {
/* no X-char, try to push chars out in DMA mode */
bool ret = true;
if (!uap->dmatx.queued) {
if (pl011_dma_tx_refill(uap) > 0) {
uap->im &= ~UART011_TXIM;
ret = true;
} else {
uap->im |= UART011_TXIM;
ret = false;
}
writew(uap->im, uap->port.membase + UART011_IMSC);
} else if (!(uap->dmacr & UART011_TXDMAE)) {
uap->dmacr |= UART011_TXDMAE;
writew(uap->dmacr,
uap->port.membase + UART011_DMACR);
}
return ret;
}
/*
* We have an X-char to send. Disable DMA to prevent it loading
* the TX fifo, and then see if we can stuff it into the FIFO.
*/
dmacr = uap->dmacr;
uap->dmacr &= ~UART011_TXDMAE;
writew(uap->dmacr, uap->port.membase + UART011_DMACR);
if (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF) {
/*
* No space in the FIFO, so enable the transmit interrupt
* so we know when there is space. Note that once we've
* loaded the character, we should just re-enable DMA.
*/
return false;
}
writew(uap->port.x_char, uap->port.membase + UART01x_DR);
uap->port.icount.tx++;
uap->port.x_char = 0;
/* Success - restore the DMA state */
uap->dmacr = dmacr;
writew(dmacr, uap->port.membase + UART011_DMACR);
return true;
}
/*
* Flush the transmit buffer.
* Locking: called with port lock held and IRQs disabled.
*/
static void pl011_dma_flush_buffer(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
if (!uap->using_tx_dma)
return;
/* Avoid deadlock with the DMA engine callback */
spin_unlock(&uap->port.lock);
dmaengine_terminate_all(uap->dmatx.chan);
spin_lock(&uap->port.lock);
if (uap->dmatx.queued) {
dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
DMA_TO_DEVICE);
uap->dmatx.queued = false;
uap->dmacr &= ~UART011_TXDMAE;
writew(uap->dmacr, uap->port.membase + UART011_DMACR);
}
}
static void pl011_dma_rx_callback(void *data);
static int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
{
struct dma_chan *rxchan = uap->dmarx.chan;
struct pl011_dmarx_data *dmarx = &uap->dmarx;
struct dma_async_tx_descriptor *desc;
struct pl011_sgbuf *sgbuf;
if (!rxchan)
return -EIO;
/* Start the RX DMA job */
sgbuf = uap->dmarx.use_buf_b ?
&uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
desc = dmaengine_prep_slave_sg(rxchan, &sgbuf->sg, 1,
DMA_DEV_TO_MEM,
DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
/*
* If the DMA engine is busy and cannot prepare a
* channel, no big deal, the driver will fall back
* to interrupt mode as a result of this error code.
*/
if (!desc) {
uap->dmarx.running = false;
dmaengine_terminate_all(rxchan);
return -EBUSY;
}
/* Some data to go along to the callback */
desc->callback = pl011_dma_rx_callback;
desc->callback_param = uap;
dmarx->cookie = dmaengine_submit(desc);
dma_async_issue_pending(rxchan);
uap->dmacr |= UART011_RXDMAE;
writew(uap->dmacr, uap->port.membase + UART011_DMACR);
uap->dmarx.running = true;
uap->im &= ~UART011_RXIM;
writew(uap->im, uap->port.membase + UART011_IMSC);
return 0;
}
/*
* This is called when either the DMA job is complete, or
* the FIFO timeout interrupt occurred. This must be called
* with the port spinlock uap->port.lock held.
*/
static void pl011_dma_rx_chars(struct uart_amba_port *uap,
u32 pending, bool use_buf_b,
bool readfifo)
{
struct tty_struct *tty = uap->port.state->port.tty;
struct pl011_sgbuf *sgbuf = use_buf_b ?
&uap->dmarx.sgbuf_b : &uap->dmarx.sgbuf_a;
struct device *dev = uap->dmarx.chan->device->dev;
int dma_count = 0;
u32 fifotaken = 0; /* only used for vdbg() */
/* Pick everything from the DMA first */
if (pending) {
/* Sync in buffer */
dma_sync_sg_for_cpu(dev, &sgbuf->sg, 1, DMA_FROM_DEVICE);
/*
* First take all chars in the DMA pipe, then look in the FIFO.
* Note that tty_insert_flip_buf() tries to take as many chars
* as it can.
*/
dma_count = tty_insert_flip_string(uap->port.state->port.tty,
sgbuf->buf, pending);
/* Return buffer to device */
dma_sync_sg_for_device(dev, &sgbuf->sg, 1, DMA_FROM_DEVICE);
uap->port.icount.rx += dma_count;
if (dma_count < pending)
dev_warn(uap->port.dev,
"couldn't insert all characters (TTY is full?)\n");
}
/*
* Only continue with trying to read the FIFO if all DMA chars have
* been taken first.
*/
if (dma_count == pending && readfifo) {
/* Clear any error flags */
writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS,
uap->port.membase + UART011_ICR);
/*
* If we read all the DMA'd characters, and we had an
* incomplete buffer, that could be due to an rx error, or
* maybe we just timed out. Read any pending chars and check
* the error status.
*
* Error conditions will only occur in the FIFO, these will
* trigger an immediate interrupt and stop the DMA job, so we
* will always find the error in the FIFO, never in the DMA
* buffer.
*/
fifotaken = pl011_fifo_to_tty(uap);
}
spin_unlock(&uap->port.lock);
dev_vdbg(uap->port.dev,
"Took %d chars from DMA buffer and %d chars from the FIFO\n",
dma_count, fifotaken);
tty_flip_buffer_push(tty);
spin_lock(&uap->port.lock);
}
static void pl011_dma_rx_irq(struct uart_amba_port *uap)
{
struct pl011_dmarx_data *dmarx = &uap->dmarx;
struct dma_chan *rxchan = dmarx->chan;
struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ?
&dmarx->sgbuf_b : &dmarx->sgbuf_a;
size_t pending;
struct dma_tx_state state;
enum dma_status dmastat;
/*
* Pause the transfer so we can trust the current counter,
* do this before we pause the PL011 block, else we may
* overflow the FIFO.
*/
if (dmaengine_pause(rxchan))
dev_err(uap->port.dev, "unable to pause DMA transfer\n");
dmastat = rxchan->device->device_tx_status(rxchan,
dmarx->cookie, &state);
if (dmastat != DMA_PAUSED)
dev_err(uap->port.dev, "unable to pause DMA transfer\n");
/* Disable RX DMA - incoming data will wait in the FIFO */
uap->dmacr &= ~UART011_RXDMAE;
writew(uap->dmacr, uap->port.membase + UART011_DMACR);
uap->dmarx.running = false;
pending = sgbuf->sg.length - state.residue;
BUG_ON(pending > PL011_DMA_BUFFER_SIZE);
/* Then we terminate the transfer - we now know our residue */
dmaengine_terminate_all(rxchan);
/*
* This will take the chars we have so far and insert
* into the framework.
*/
pl011_dma_rx_chars(uap, pending, dmarx->use_buf_b, true);
/* Switch buffer & re-trigger DMA job */
dmarx->use_buf_b = !dmarx->use_buf_b;
if (pl011_dma_rx_trigger_dma(uap)) {
dev_dbg(uap->port.dev, "could not retrigger RX DMA job "
"fall back to interrupt mode\n");
uap->im |= UART011_RXIM;
writew(uap->im, uap->port.membase + UART011_IMSC);
}
}
static void pl011_dma_rx_callback(void *data)
{
struct uart_amba_port *uap = data;
struct pl011_dmarx_data *dmarx = &uap->dmarx;
struct dma_chan *rxchan = dmarx->chan;
bool lastbuf = dmarx->use_buf_b;
struct pl011_sgbuf *sgbuf = dmarx->use_buf_b ?
&dmarx->sgbuf_b : &dmarx->sgbuf_a;
size_t pending;
struct dma_tx_state state;
int ret;
/*
* This completion interrupt occurs typically when the
* RX buffer is totally stuffed but no timeout has yet
* occurred. When that happens, we just want the RX
* routine to flush out the secondary DMA buffer while
* we immediately trigger the next DMA job.
*/
spin_lock_irq(&uap->port.lock);
/*
* Rx data can be taken by the UART interrupts during
* the DMA irq handler. So we check the residue here.
*/
rxchan->device->device_tx_status(rxchan, dmarx->cookie, &state);
pending = sgbuf->sg.length - state.residue;
BUG_ON(pending > PL011_DMA_BUFFER_SIZE);
/* Then we terminate the transfer - we now know our residue */
dmaengine_terminate_all(rxchan);
uap->dmarx.running = false;
dmarx->use_buf_b = !lastbuf;
ret = pl011_dma_rx_trigger_dma(uap);
pl011_dma_rx_chars(uap, pending, lastbuf, false);
spin_unlock_irq(&uap->port.lock);
/*
* Do this check after we picked the DMA chars so we don't
* get some IRQ immediately from RX.
*/
if (ret) {
dev_dbg(uap->port.dev, "could not retrigger RX DMA job "
"fall back to interrupt mode\n");
uap->im |= UART011_RXIM;
writew(uap->im, uap->port.membase + UART011_IMSC);
}
}
/*
* Stop accepting received characters, when we're shutting down or
* suspending this port.
* Locking: called with port lock held and IRQs disabled.
*/
static inline void pl011_dma_rx_stop(struct uart_amba_port *uap)
{
/* FIXME. Just disable the DMA enable */
uap->dmacr &= ~UART011_RXDMAE;
writew(uap->dmacr, uap->port.membase + UART011_DMACR);
}
static void pl011_dma_startup(struct uart_amba_port *uap)
{
int ret;
if (!uap->dmatx.chan)
return;
uap->dmatx.buf = kmalloc(PL011_DMA_BUFFER_SIZE, GFP_KERNEL);
if (!uap->dmatx.buf) {
dev_err(uap->port.dev, "no memory for DMA TX buffer\n");
uap->port.fifosize = uap->fifosize;
return;
}
sg_init_one(&uap->dmatx.sg, uap->dmatx.buf, PL011_DMA_BUFFER_SIZE);
/* The DMA buffer is now the FIFO the TTY subsystem can use */
uap->port.fifosize = PL011_DMA_BUFFER_SIZE;
uap->using_tx_dma = true;
if (!uap->dmarx.chan)
goto skip_rx;
/* Allocate and map DMA RX buffers */
ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
DMA_FROM_DEVICE);
if (ret) {
dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
"RX buffer A", ret);
goto skip_rx;
}
ret = pl011_sgbuf_init(uap->dmarx.chan, &uap->dmarx.sgbuf_b,
DMA_FROM_DEVICE);
if (ret) {
dev_err(uap->port.dev, "failed to init DMA %s: %d\n",
"RX buffer B", ret);
pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a,
DMA_FROM_DEVICE);
goto skip_rx;
}
uap->using_rx_dma = true;
skip_rx:
/* Turn on DMA error (RX/TX will be enabled on demand) */
uap->dmacr |= UART011_DMAONERR;
writew(uap->dmacr, uap->port.membase + UART011_DMACR);
/*
* ST Micro variants has some specific dma burst threshold
* compensation. Set this to 16 bytes, so burst will only
* be issued above/below 16 bytes.
*/
if (uap->vendor->dma_threshold)
writew(ST_UART011_DMAWM_RX_16 | ST_UART011_DMAWM_TX_16,
uap->port.membase + ST_UART011_DMAWM);
if (uap->using_rx_dma) {
if (pl011_dma_rx_trigger_dma(uap))
dev_dbg(uap->port.dev, "could not trigger initial "
"RX DMA job, fall back to interrupt mode\n");
}
}
static void pl011_dma_shutdown(struct uart_amba_port *uap)
{
if (!(uap->using_tx_dma || uap->using_rx_dma))
return;
/* Disable RX and TX DMA */
while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY)
barrier();
spin_lock_irq(&uap->port.lock);
uap->dmacr &= ~(UART011_DMAONERR | UART011_RXDMAE | UART011_TXDMAE);
writew(uap->dmacr, uap->port.membase + UART011_DMACR);
spin_unlock_irq(&uap->port.lock);
if (uap->using_tx_dma) {
/* In theory, this should already be done by pl011_dma_flush_buffer */
dmaengine_terminate_all(uap->dmatx.chan);
if (uap->dmatx.queued) {
dma_unmap_sg(uap->dmatx.chan->device->dev, &uap->dmatx.sg, 1,
DMA_TO_DEVICE);
uap->dmatx.queued = false;
}
kfree(uap->dmatx.buf);
uap->using_tx_dma = false;
}
if (uap->using_rx_dma) {
dmaengine_terminate_all(uap->dmarx.chan);
/* Clean up the RX DMA */
pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_a, DMA_FROM_DEVICE);
pl011_sgbuf_free(uap->dmarx.chan, &uap->dmarx.sgbuf_b, DMA_FROM_DEVICE);
uap->using_rx_dma = false;
}
}
static inline bool pl011_dma_rx_available(struct uart_amba_port *uap)
{
return uap->using_rx_dma;
}
static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
{
return uap->using_rx_dma && uap->dmarx.running;
}
#else
/* Blank functions if the DMA engine is not available */
static inline void pl011_dma_probe(struct uart_amba_port *uap)
{
}
static inline void pl011_dma_remove(struct uart_amba_port *uap)
{
}
static inline void pl011_dma_startup(struct uart_amba_port *uap)
{
}
static inline void pl011_dma_shutdown(struct uart_amba_port *uap)
{
}
static inline bool pl011_dma_tx_irq(struct uart_amba_port *uap)
{
return false;
}
static inline void pl011_dma_tx_stop(struct uart_amba_port *uap)
{
}
static inline bool pl011_dma_tx_start(struct uart_amba_port *uap)
{
return false;
}
static inline void pl011_dma_rx_irq(struct uart_amba_port *uap)
{
}
static inline void pl011_dma_rx_stop(struct uart_amba_port *uap)
{
}
static inline int pl011_dma_rx_trigger_dma(struct uart_amba_port *uap)
{
return -EIO;
}
static inline bool pl011_dma_rx_available(struct uart_amba_port *uap)
{
return false;
}
static inline bool pl011_dma_rx_running(struct uart_amba_port *uap)
{
return false;
}
#define pl011_dma_flush_buffer NULL
#endif
static void pl011_stop_tx(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
uap->im &= ~UART011_TXIM;
writew(uap->im, uap->port.membase + UART011_IMSC);
pl011_dma_tx_stop(uap);
}
static void pl011_start_tx(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
if (!pl011_dma_tx_start(uap)) {
uap->im |= UART011_TXIM;
writew(uap->im, uap->port.membase + UART011_IMSC);
}
}
static void pl011_stop_rx(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
uap->im &= ~(UART011_RXIM|UART011_RTIM|UART011_FEIM|
UART011_PEIM|UART011_BEIM|UART011_OEIM);
writew(uap->im, uap->port.membase + UART011_IMSC);
pl011_dma_rx_stop(uap);
}
static void pl011_enable_ms(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
uap->im |= UART011_RIMIM|UART011_CTSMIM|UART011_DCDMIM|UART011_DSRMIM;
writew(uap->im, uap->port.membase + UART011_IMSC);
}
static void pl011_rx_chars(struct uart_amba_port *uap)
{
struct tty_struct *tty = uap->port.state->port.tty;
pl011_fifo_to_tty(uap);
spin_unlock(&uap->port.lock);
tty_flip_buffer_push(tty);
/*
* If we were temporarily out of DMA mode for a while,
* attempt to switch back to DMA mode again.
*/
if (pl011_dma_rx_available(uap)) {
if (pl011_dma_rx_trigger_dma(uap)) {
dev_dbg(uap->port.dev, "could not trigger RX DMA job "
"fall back to interrupt mode again\n");
uap->im |= UART011_RXIM;
} else
uap->im &= ~UART011_RXIM;
writew(uap->im, uap->port.membase + UART011_IMSC);
}
spin_lock(&uap->port.lock);
}
static void pl011_tx_chars(struct uart_amba_port *uap)
{
struct circ_buf *xmit = &uap->port.state->xmit;
int count;
if (uap->port.x_char) {
writew(uap->port.x_char, uap->port.membase + UART01x_DR);
uap->port.icount.tx++;
uap->port.x_char = 0;
return;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(&uap->port)) {
pl011_stop_tx(&uap->port);
return;
}
/* If we are using DMA mode, try to send some characters. */
if (pl011_dma_tx_irq(uap))
return;
count = uap->fifosize >> 1;
do {
writew(xmit->buf[xmit->tail], uap->port.membase + UART01x_DR);
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
uap->port.icount.tx++;
if (uart_circ_empty(xmit))
break;
} while (--count > 0);
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(&uap->port);
if (uart_circ_empty(xmit))
pl011_stop_tx(&uap->port);
}
static void pl011_modem_status(struct uart_amba_port *uap)
{
unsigned int status, delta;
status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
delta = status ^ uap->old_status;
uap->old_status = status;
if (!delta)
return;
if (delta & UART01x_FR_DCD)
uart_handle_dcd_change(&uap->port, status & UART01x_FR_DCD);
if (delta & UART01x_FR_DSR)
uap->port.icount.dsr++;
if (delta & UART01x_FR_CTS)
uart_handle_cts_change(&uap->port, status & UART01x_FR_CTS);
wake_up_interruptible(&uap->port.state->port.delta_msr_wait);
}
static irqreturn_t pl011_int(int irq, void *dev_id)
{
struct uart_amba_port *uap = dev_id;
unsigned long flags;
unsigned int status, pass_counter = AMBA_ISR_PASS_LIMIT;
int handled = 0;
unsigned int dummy_read;
spin_lock_irqsave(&uap->port.lock, flags);
status = readw(uap->port.membase + UART011_MIS);
if (status) {
do {
if (uap->vendor->cts_event_workaround) {
/* workaround to make sure that all bits are unlocked.. */
writew(0x00, uap->port.membase + UART011_ICR);
/*
* WA: introduce 26ns(1 uart clk) delay before W1C;
* single apb access will incur 2 pclk(133.12Mhz) delay,
* so add 2 dummy reads
*/
dummy_read = readw(uap->port.membase + UART011_ICR);
dummy_read = readw(uap->port.membase + UART011_ICR);
}
writew(status & ~(UART011_TXIS|UART011_RTIS|
UART011_RXIS),
uap->port.membase + UART011_ICR);
if (status & (UART011_RTIS|UART011_RXIS)) {
if (pl011_dma_rx_running(uap))
pl011_dma_rx_irq(uap);
else
pl011_rx_chars(uap);
}
if (status & (UART011_DSRMIS|UART011_DCDMIS|
UART011_CTSMIS|UART011_RIMIS))
pl011_modem_status(uap);
if (status & UART011_TXIS)
pl011_tx_chars(uap);
if (pass_counter-- == 0)
break;
status = readw(uap->port.membase + UART011_MIS);
} while (status != 0);
handled = 1;
}
spin_unlock_irqrestore(&uap->port.lock, flags);
return IRQ_RETVAL(handled);
}
static unsigned int pl011_tx_empty(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
unsigned int status = readw(uap->port.membase + UART01x_FR);
return status & (UART01x_FR_BUSY|UART01x_FR_TXFF) ? 0 : TIOCSER_TEMT;
}
static unsigned int pl011_get_mctrl(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
unsigned int result = 0;
unsigned int status = readw(uap->port.membase + UART01x_FR);
#define TIOCMBIT(uartbit, tiocmbit) \
if (status & uartbit) \
result |= tiocmbit
TIOCMBIT(UART01x_FR_DCD, TIOCM_CAR);
TIOCMBIT(UART01x_FR_DSR, TIOCM_DSR);
TIOCMBIT(UART01x_FR_CTS, TIOCM_CTS);
TIOCMBIT(UART011_FR_RI, TIOCM_RNG);
#undef TIOCMBIT
return result;
}
static void pl011_set_mctrl(struct uart_port *port, unsigned int mctrl)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
unsigned int cr;
cr = readw(uap->port.membase + UART011_CR);
#define TIOCMBIT(tiocmbit, uartbit) \
if (mctrl & tiocmbit) \
cr |= uartbit; \
else \
cr &= ~uartbit
TIOCMBIT(TIOCM_RTS, UART011_CR_RTS);
TIOCMBIT(TIOCM_DTR, UART011_CR_DTR);
TIOCMBIT(TIOCM_OUT1, UART011_CR_OUT1);
TIOCMBIT(TIOCM_OUT2, UART011_CR_OUT2);
TIOCMBIT(TIOCM_LOOP, UART011_CR_LBE);
if (uap->autorts) {
/* We need to disable auto-RTS if we want to turn RTS off */
TIOCMBIT(TIOCM_RTS, UART011_CR_RTSEN);
}
#undef TIOCMBIT
writew(cr, uap->port.membase + UART011_CR);
}
static void pl011_break_ctl(struct uart_port *port, int break_state)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
unsigned long flags;
unsigned int lcr_h;
spin_lock_irqsave(&uap->port.lock, flags);
lcr_h = readw(uap->port.membase + uap->lcrh_tx);
if (break_state == -1)
lcr_h |= UART01x_LCRH_BRK;
else
lcr_h &= ~UART01x_LCRH_BRK;
writew(lcr_h, uap->port.membase + uap->lcrh_tx);
spin_unlock_irqrestore(&uap->port.lock, flags);
}
#ifdef CONFIG_CONSOLE_POLL
static void pl011_quiesce_irqs(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
unsigned char __iomem *regs = uap->port.membase;
writew(readw(regs + UART011_MIS), regs + UART011_ICR);
/*
* There is no way to clear TXIM as this is "ready to transmit IRQ", so
* we simply mask it. start_tx() will unmask it.
*
* Note we can race with start_tx(), and if the race happens, the
* polling user might get another interrupt just after we clear it.
* But it should be OK and can happen even w/o the race, e.g.
* controller immediately got some new data and raised the IRQ.
*
* And whoever uses polling routines assumes that it manages the device
* (including tx queue), so we're also fine with start_tx()'s caller
* side.
*/
writew(readw(regs + UART011_IMSC) & ~UART011_TXIM, regs + UART011_IMSC);
}
static int pl011_get_poll_char(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
unsigned int status;
/*
* The caller might need IRQs lowered, e.g. if used with KDB NMI
* debugger.
*/
pl011_quiesce_irqs(port);
status = readw(uap->port.membase + UART01x_FR);
if (status & UART01x_FR_RXFE)
return NO_POLL_CHAR;
return readw(uap->port.membase + UART01x_DR);
}
static void pl011_put_poll_char(struct uart_port *port,
unsigned char ch)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF)
barrier();
writew(ch, uap->port.membase + UART01x_DR);
}
#endif /* CONFIG_CONSOLE_POLL */
static int pl011_hwinit(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
int retval;
/* Optionaly enable pins to be muxed in and configured */
if (!IS_ERR(uap->pins_default)) {
retval = pinctrl_select_state(uap->pinctrl, uap->pins_default);
if (retval)
dev_err(port->dev,
"could not set default pins\n");
}
/*
* Try to enable the clock producer.
*/
retval = clk_prepare_enable(uap->clk);
if (retval)
goto out;
uap->port.uartclk = clk_get_rate(uap->clk);
/* Clear pending error and receive interrupts */
writew(UART011_OEIS | UART011_BEIS | UART011_PEIS | UART011_FEIS |
UART011_RTIS | UART011_RXIS, uap->port.membase + UART011_ICR);
/*
* Save interrupts enable mask, and enable RX interrupts in case if
* the interrupt is used for NMI entry.
*/
uap->im = readw(uap->port.membase + UART011_IMSC);
writew(UART011_RTIM | UART011_RXIM, uap->port.membase + UART011_IMSC);
if (uap->port.dev->platform_data) {
struct amba_pl011_data *plat;
plat = uap->port.dev->platform_data;
if (plat->init)
plat->init();
}
return 0;
out:
return retval;
}
static int pl011_startup(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
unsigned int cr;
int retval;
retval = pl011_hwinit(port);
if (retval)
goto clk_dis;
writew(uap->im, uap->port.membase + UART011_IMSC);
/*
* Allocate the IRQ
*/
retval = request_irq(uap->port.irq, pl011_int, 0, "uart-pl011", uap);
if (retval)
goto clk_dis;
writew(uap->vendor->ifls, uap->port.membase + UART011_IFLS);
/*
* Provoke TX FIFO interrupt into asserting.
*/
cr = UART01x_CR_UARTEN | UART011_CR_TXE | UART011_CR_LBE;
writew(cr, uap->port.membase + UART011_CR);
writew(0, uap->port.membase + UART011_FBRD);
writew(1, uap->port.membase + UART011_IBRD);
writew(0, uap->port.membase + uap->lcrh_rx);
if (uap->lcrh_tx != uap->lcrh_rx) {
int i;
/*
* Wait 10 PCLKs before writing LCRH_TX register,
* to get this delay write read only register 10 times
*/
for (i = 0; i < 10; ++i)
writew(0xff, uap->port.membase + UART011_MIS);
writew(0, uap->port.membase + uap->lcrh_tx);
}
writew(0, uap->port.membase + UART01x_DR);
while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_BUSY)
barrier();
/* restore RTS and DTR */
cr = uap->old_cr & (UART011_CR_RTS | UART011_CR_DTR);
cr |= UART01x_CR_UARTEN | UART011_CR_RXE | UART011_CR_TXE;
writew(cr, uap->port.membase + UART011_CR);
/*
* initialise the old status of the modem signals
*/
uap->old_status = readw(uap->port.membase + UART01x_FR) & UART01x_FR_MODEM_ANY;
/* Startup DMA */
pl011_dma_startup(uap);
/*
* Finally, enable interrupts, only timeouts when using DMA
* if initial RX DMA job failed, start in interrupt mode
* as well.
*/
spin_lock_irq(&uap->port.lock);
/* Clear out any spuriously appearing RX interrupts */
writew(UART011_RTIS | UART011_RXIS,
uap->port.membase + UART011_ICR);
uap->im = UART011_RTIM;
if (!pl011_dma_rx_running(uap))
uap->im |= UART011_RXIM;
writew(uap->im, uap->port.membase + UART011_IMSC);
spin_unlock_irq(&uap->port.lock);
return 0;
clk_dis:
clk_disable_unprepare(uap->clk);
return retval;
}
static void pl011_shutdown_channel(struct uart_amba_port *uap,
unsigned int lcrh)
{
unsigned long val;
val = readw(uap->port.membase + lcrh);
val &= ~(UART01x_LCRH_BRK | UART01x_LCRH_FEN);
writew(val, uap->port.membase + lcrh);
}
static void pl011_shutdown(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
unsigned int cr;
int retval;
/*
* disable all interrupts
*/
spin_lock_irq(&uap->port.lock);
uap->im = 0;
writew(uap->im, uap->port.membase + UART011_IMSC);
writew(0xffff, uap->port.membase + UART011_ICR);
spin_unlock_irq(&uap->port.lock);
pl011_dma_shutdown(uap);
/*
* Free the interrupt
*/
free_irq(uap->port.irq, uap);
/*
* disable the port
* disable the port. It should not disable RTS and DTR.
* Also RTS and DTR state should be preserved to restore
* it during startup().
*/
uap->autorts = false;
cr = readw(uap->port.membase + UART011_CR);
uap->old_cr = cr;
cr &= UART011_CR_RTS | UART011_CR_DTR;
cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
writew(cr, uap->port.membase + UART011_CR);
/*
* disable break condition and fifos
*/
pl011_shutdown_channel(uap, uap->lcrh_rx);
if (uap->lcrh_rx != uap->lcrh_tx)
pl011_shutdown_channel(uap, uap->lcrh_tx);
/*
* Shut down the clock producer
*/
clk_disable_unprepare(uap->clk);
/* Optionally let pins go into sleep states */
if (!IS_ERR(uap->pins_sleep)) {
retval = pinctrl_select_state(uap->pinctrl, uap->pins_sleep);
if (retval)
dev_err(port->dev,
"could not set pins to sleep state\n");
}
if (uap->port.dev->platform_data) {
struct amba_pl011_data *plat;
plat = uap->port.dev->platform_data;
if (plat->exit)
plat->exit();
}
}
static void
pl011_set_termios(struct uart_port *port, struct ktermios *termios,
struct ktermios *old)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
unsigned int lcr_h, old_cr;
unsigned long flags;
unsigned int baud, quot, clkdiv;
if (uap->vendor->oversampling)
clkdiv = 8;
else
clkdiv = 16;
/*
* Ask the core to calculate the divisor for us.
*/
baud = uart_get_baud_rate(port, termios, old, 0,
port->uartclk / clkdiv);
if (baud > port->uartclk/16)
quot = DIV_ROUND_CLOSEST(port->uartclk * 8, baud);
else
quot = DIV_ROUND_CLOSEST(port->uartclk * 4, baud);
switch (termios->c_cflag & CSIZE) {
case CS5:
lcr_h = UART01x_LCRH_WLEN_5;
break;
case CS6:
lcr_h = UART01x_LCRH_WLEN_6;
break;
case CS7:
lcr_h = UART01x_LCRH_WLEN_7;
break;
default: // CS8
lcr_h = UART01x_LCRH_WLEN_8;
break;
}
if (termios->c_cflag & CSTOPB)
lcr_h |= UART01x_LCRH_STP2;
if (termios->c_cflag & PARENB) {
lcr_h |= UART01x_LCRH_PEN;
if (!(termios->c_cflag & PARODD))
lcr_h |= UART01x_LCRH_EPS;
}
if (uap->fifosize > 1)
lcr_h |= UART01x_LCRH_FEN;
spin_lock_irqsave(&port->lock, flags);
/*
* Update the per-port timeout.
*/
uart_update_timeout(port, termios->c_cflag, baud);
port->read_status_mask = UART011_DR_OE | 255;
if (termios->c_iflag & INPCK)
port->read_status_mask |= UART011_DR_FE | UART011_DR_PE;
if (termios->c_iflag & (BRKINT | PARMRK))
port->read_status_mask |= UART011_DR_BE;
/*
* Characters to ignore
*/
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= UART011_DR_FE | UART011_DR_PE;
if (termios->c_iflag & IGNBRK) {
port->ignore_status_mask |= UART011_DR_BE;
/*
* If we're ignoring parity and break indicators,
* ignore overruns too (for real raw support).
*/
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |= UART011_DR_OE;
}
/*
* Ignore all characters if CREAD is not set.
*/
if ((termios->c_cflag & CREAD) == 0)
port->ignore_status_mask |= UART_DUMMY_DR_RX;
if (UART_ENABLE_MS(port, termios->c_cflag))
pl011_enable_ms(port);
/* first, disable everything */
old_cr = readw(port->membase + UART011_CR);
writew(0, port->membase + UART011_CR);
if (termios->c_cflag & CRTSCTS) {
if (old_cr & UART011_CR_RTS)
old_cr |= UART011_CR_RTSEN;
old_cr |= UART011_CR_CTSEN;
uap->autorts = true;
} else {
old_cr &= ~(UART011_CR_CTSEN | UART011_CR_RTSEN);
uap->autorts = false;
}
if (uap->vendor->oversampling) {
if (baud > port->uartclk / 16)
old_cr |= ST_UART011_CR_OVSFACT;
else
old_cr &= ~ST_UART011_CR_OVSFACT;
}
/*
* Workaround for the ST Micro oversampling variants to
* increase the bitrate slightly, by lowering the divisor,
* to avoid delayed sampling of start bit at high speeds,
* else we see data corruption.
*/
if (uap->vendor->oversampling) {
if ((baud >= 3000000) && (baud < 3250000) && (quot > 1))
quot -= 1;
else if ((baud > 3250000) && (quot > 2))
quot -= 2;
}
/* Set baud rate */
writew(quot & 0x3f, port->membase + UART011_FBRD);
writew(quot >> 6, port->membase + UART011_IBRD);
/*
* ----------v----------v----------v----------v-----
* NOTE: lcrh_tx and lcrh_rx MUST BE WRITTEN AFTER
* UART011_FBRD & UART011_IBRD.
* ----------^----------^----------^----------^-----
*/
writew(lcr_h, port->membase + uap->lcrh_rx);
if (uap->lcrh_rx != uap->lcrh_tx) {
int i;
/*
* Wait 10 PCLKs before writing LCRH_TX register,
* to get this delay write read only register 10 times
*/
for (i = 0; i < 10; ++i)
writew(0xff, uap->port.membase + UART011_MIS);
writew(lcr_h, port->membase + uap->lcrh_tx);
}
writew(old_cr, port->membase + UART011_CR);
spin_unlock_irqrestore(&port->lock, flags);
}
static const char *pl011_type(struct uart_port *port)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
return uap->port.type == PORT_AMBA ? uap->type : NULL;
}
/*
* Release the memory region(s) being used by 'port'
*/
static void pl011_release_port(struct uart_port *port)
{
release_mem_region(port->mapbase, SZ_4K);
}
/*
* Request the memory region(s) being used by 'port'
*/
static int pl011_request_port(struct uart_port *port)
{
return request_mem_region(port->mapbase, SZ_4K, "uart-pl011")
!= NULL ? 0 : -EBUSY;
}
/*
* Configure/autoconfigure the port.
*/
static void pl011_config_port(struct uart_port *port, int flags)
{
if (flags & UART_CONFIG_TYPE) {
port->type = PORT_AMBA;
pl011_request_port(port);
}
}
/*
* verify the new serial_struct (for TIOCSSERIAL).
*/
static int pl011_verify_port(struct uart_port *port, struct serial_struct *ser)
{
int ret = 0;
if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
ret = -EINVAL;
if (ser->irq < 0 || ser->irq >= nr_irqs)
ret = -EINVAL;
if (ser->baud_base < 9600)
ret = -EINVAL;
return ret;
}
static struct uart_ops amba_pl011_pops = {
.tx_empty = pl011_tx_empty,
.set_mctrl = pl011_set_mctrl,
.get_mctrl = pl011_get_mctrl,
.stop_tx = pl011_stop_tx,
.start_tx = pl011_start_tx,
.stop_rx = pl011_stop_rx,
.enable_ms = pl011_enable_ms,
.break_ctl = pl011_break_ctl,
.startup = pl011_startup,
.shutdown = pl011_shutdown,
.flush_buffer = pl011_dma_flush_buffer,
.set_termios = pl011_set_termios,
.type = pl011_type,
.release_port = pl011_release_port,
.request_port = pl011_request_port,
.config_port = pl011_config_port,
.verify_port = pl011_verify_port,
#ifdef CONFIG_CONSOLE_POLL
.poll_init = pl011_hwinit,
.poll_get_char = pl011_get_poll_char,
.poll_put_char = pl011_put_poll_char,
#endif
};
static struct uart_amba_port *amba_ports[UART_NR];
#ifdef CONFIG_SERIAL_AMBA_PL011_CONSOLE
static void pl011_console_putchar(struct uart_port *port, int ch)
{
struct uart_amba_port *uap = (struct uart_amba_port *)port;
while (readw(uap->port.membase + UART01x_FR) & UART01x_FR_TXFF)
barrier();
writew(ch, uap->port.membase + UART01x_DR);
}
static void
pl011_console_write(struct console *co, const char *s, unsigned int count)
{
struct uart_amba_port *uap = amba_ports[co->index];
unsigned int status, old_cr, new_cr;
unsigned long flags;
int locked = 1;
clk_enable(uap->clk);
local_irq_save(flags);
if (uap->port.sysrq)
locked = 0;
else if (oops_in_progress)
locked = spin_trylock(&uap->port.lock);
else
spin_lock(&uap->port.lock);
/*
* First save the CR then disable the interrupts
*/
old_cr = readw(uap->port.membase + UART011_CR);
new_cr = old_cr & ~UART011_CR_CTSEN;
new_cr |= UART01x_CR_UARTEN | UART011_CR_TXE;
writew(new_cr, uap->port.membase + UART011_CR);
uart_console_write(&uap->port, s, count, pl011_console_putchar);
/*
* Finally, wait for transmitter to become empty
* and restore the TCR
*/
do {
status = readw(uap->port.membase + UART01x_FR);
} while (status & UART01x_FR_BUSY);
writew(old_cr, uap->port.membase + UART011_CR);
if (locked)
spin_unlock(&uap->port.lock);
local_irq_restore(flags);
clk_disable(uap->clk);
}
static void __init
pl011_console_get_options(struct uart_amba_port *uap, int *baud,
int *parity, int *bits)
{
if (readw(uap->port.membase + UART011_CR) & UART01x_CR_UARTEN) {
unsigned int lcr_h, ibrd, fbrd;
lcr_h = readw(uap->port.membase + uap->lcrh_tx);
*parity = 'n';
if (lcr_h & UART01x_LCRH_PEN) {
if (lcr_h & UART01x_LCRH_EPS)
*parity = 'e';
else
*parity = 'o';
}
if ((lcr_h & 0x60) == UART01x_LCRH_WLEN_7)
*bits = 7;
else
*bits = 8;
ibrd = readw(uap->port.membase + UART011_IBRD);
fbrd = readw(uap->port.membase + UART011_FBRD);
*baud = uap->port.uartclk * 4 / (64 * ibrd + fbrd);
if (uap->vendor->oversampling) {
if (readw(uap->port.membase + UART011_CR)
& ST_UART011_CR_OVSFACT)
*baud *= 2;
}
}
}
static int __init pl011_console_setup(struct console *co, char *options)
{
struct uart_amba_port *uap;
int baud = 38400;
int bits = 8;
int parity = 'n';
int flow = 'n';
int ret;
/*
* Check whether an invalid uart number has been specified, and
* if so, search for the first available port that does have
* console support.
*/
if (co->index >= UART_NR)
co->index = 0;
uap = amba_ports[co->index];
if (!uap)
return -ENODEV;
/* Allow pins to be muxed in and configured */
if (!IS_ERR(uap->pins_default)) {
ret = pinctrl_select_state(uap->pinctrl, uap->pins_default);
if (ret)
dev_err(uap->port.dev,
"could not set default pins\n");
}
ret = clk_prepare(uap->clk);
if (ret)
return ret;
if (uap->port.dev->platform_data) {
struct amba_pl011_data *plat;
plat = uap->port.dev->platform_data;
if (plat->init)
plat->init();
}
uap->port.uartclk = clk_get_rate(uap->clk);
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
else
pl011_console_get_options(uap, &baud, &parity, &bits);
return uart_set_options(&uap->port, co, baud, parity, bits, flow);
}
static struct uart_driver amba_reg;
static struct console amba_console = {
.name = "ttyAMA",
.write = pl011_console_write,
.device = uart_console_device,
.setup = pl011_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &amba_reg,
};
#define AMBA_CONSOLE (&amba_console)
#else
#define AMBA_CONSOLE NULL
#endif
static struct uart_driver amba_reg = {
.owner = THIS_MODULE,
.driver_name = "ttyAMA",
.dev_name = "ttyAMA",
.major = SERIAL_AMBA_MAJOR,
.minor = SERIAL_AMBA_MINOR,
.nr = UART_NR,
.cons = AMBA_CONSOLE,
};
static int pl011_probe_dt_alias(int index, struct device *dev)
{
struct device_node *np;
static bool seen_dev_with_alias = false;
static bool seen_dev_without_alias = false;
int ret = index;
if (!IS_ENABLED(CONFIG_OF))
return ret;
np = dev->of_node;
if (!np)
return ret;
ret = of_alias_get_id(np, "serial");
if (IS_ERR_VALUE(ret)) {
seen_dev_without_alias = true;
ret = index;
} else {
seen_dev_with_alias = true;
if (ret >= ARRAY_SIZE(amba_ports) || amba_ports[ret] != NULL) {
dev_warn(dev, "requested serial port %d not available.\n", ret);
ret = index;
}
}
if (seen_dev_with_alias && seen_dev_without_alias)
dev_warn(dev, "aliased and non-aliased serial devices found in device tree. Serial port enumeration may be unpredictable.\n");
return ret;
}
static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
{
struct uart_amba_port *uap;
struct vendor_data *vendor = id->data;
void __iomem *base;
int i, ret;
for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
if (amba_ports[i] == NULL)
break;
if (i == ARRAY_SIZE(amba_ports)) {
ret = -EBUSY;
goto out;
}
uap = kzalloc(sizeof(struct uart_amba_port), GFP_KERNEL);
if (uap == NULL) {
ret = -ENOMEM;
goto out;
}
i = pl011_probe_dt_alias(i, &dev->dev);
base = ioremap(dev->res.start, resource_size(&dev->res));
if (!base) {
ret = -ENOMEM;
goto free;
}
uap->pinctrl = devm_pinctrl_get(&dev->dev);
if (IS_ERR(uap->pinctrl)) {
ret = PTR_ERR(uap->pinctrl);
goto unmap;
}
uap->pins_default = pinctrl_lookup_state(uap->pinctrl,
PINCTRL_STATE_DEFAULT);
if (IS_ERR(uap->pins_default))
dev_err(&dev->dev, "could not get default pinstate\n");
uap->pins_sleep = pinctrl_lookup_state(uap->pinctrl,
PINCTRL_STATE_SLEEP);
if (IS_ERR(uap->pins_sleep))
dev_dbg(&dev->dev, "could not get sleep pinstate\n");
uap->clk = clk_get(&dev->dev, NULL);
if (IS_ERR(uap->clk)) {
ret = PTR_ERR(uap->clk);
goto unmap;
}
uap->vendor = vendor;
uap->lcrh_rx = vendor->lcrh_rx;
uap->lcrh_tx = vendor->lcrh_tx;
uap->old_cr = 0;
uap->fifosize = vendor->fifosize;
uap->port.dev = &dev->dev;
uap->port.mapbase = dev->res.start;
uap->port.membase = base;
uap->port.iotype = UPIO_MEM;
uap->port.irq = dev->irq[0];
uap->port.fifosize = uap->fifosize;
uap->port.ops = &amba_pl011_pops;
uap->port.flags = UPF_BOOT_AUTOCONF;
uap->port.line = i;
pl011_dma_probe(uap);
/* Ensure interrupts from this UART are masked and cleared */
writew(0, uap->port.membase + UART011_IMSC);
writew(0xffff, uap->port.membase + UART011_ICR);
snprintf(uap->type, sizeof(uap->type), "PL011 rev%u", amba_rev(dev));
amba_ports[i] = uap;
amba_set_drvdata(dev, uap);
ret = uart_add_one_port(&amba_reg, &uap->port);
if (ret) {
amba_set_drvdata(dev, NULL);
amba_ports[i] = NULL;
pl011_dma_remove(uap);
clk_put(uap->clk);
unmap:
iounmap(base);
free:
kfree(uap);
}
out:
return ret;
}
static int pl011_remove(struct amba_device *dev)
{
struct uart_amba_port *uap = amba_get_drvdata(dev);
int i;
amba_set_drvdata(dev, NULL);
uart_remove_one_port(&amba_reg, &uap->port);
for (i = 0; i < ARRAY_SIZE(amba_ports); i++)
if (amba_ports[i] == uap)
amba_ports[i] = NULL;
pl011_dma_remove(uap);
iounmap(uap->port.membase);
clk_put(uap->clk);
kfree(uap);
return 0;
}
#ifdef CONFIG_PM
static int pl011_suspend(struct amba_device *dev, pm_message_t state)
{
struct uart_amba_port *uap = amba_get_drvdata(dev);
if (!uap)
return -EINVAL;
return uart_suspend_port(&amba_reg, &uap->port);
}
static int pl011_resume(struct amba_device *dev)
{
struct uart_amba_port *uap = amba_get_drvdata(dev);
if (!uap)
return -EINVAL;
return uart_resume_port(&amba_reg, &uap->port);
}
#endif
static struct amba_id pl011_ids[] = {
{
.id = 0x00041011,
.mask = 0x000fffff,
.data = &vendor_arm,
},
{
.id = 0x00380802,
.mask = 0x00ffffff,
.data = &vendor_st,
},
{ 0, 0 },
};
MODULE_DEVICE_TABLE(amba, pl011_ids);
static struct amba_driver pl011_driver = {
.drv = {
.name = "uart-pl011",
},
.id_table = pl011_ids,
.probe = pl011_probe,
.remove = pl011_remove,
#ifdef CONFIG_PM
.suspend = pl011_suspend,
.resume = pl011_resume,
#endif
};
static int __init pl011_init(void)
{
int ret;
printk(KERN_INFO "Serial: AMBA PL011 UART driver\n");
ret = uart_register_driver(&amba_reg);
if (ret == 0) {
ret = amba_driver_register(&pl011_driver);
if (ret)
uart_unregister_driver(&amba_reg);
}
return ret;
}
static void __exit pl011_exit(void)
{
amba_driver_unregister(&pl011_driver);
uart_unregister_driver(&amba_reg);
}
/*
* While this can be a module, if builtin it's most likely the console
* So let's leave module_exit but move module_init to an earlier place
*/
arch_initcall(pl011_init);
module_exit(pl011_exit);
MODULE_AUTHOR("ARM Ltd/Deep Blue Solutions Ltd");
MODULE_DESCRIPTION("ARM AMBA serial port driver");
MODULE_LICENSE("GPL");