alistair23-linux/arch/arm/mach-omap2/serial.c

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/*
* arch/arm/mach-omap2/serial.c
*
* OMAP2 serial support.
*
* Copyright (C) 2005-2008 Nokia Corporation
* Author: Paul Mundt <paul.mundt@nokia.com>
*
* Major rework for PM support by Kevin Hilman
*
* Based off of arch/arm/mach-omap/omap1/serial.c
*
* Copyright (C) 2009 Texas Instruments
* Added OMAP4 support - Santosh Shilimkar <santosh.shilimkar@ti.com
*
* This file is subject to the terms and conditions of the GNU General Public
* License. See the file "COPYING" in the main directory of this archive
* for more details.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/serial_reg.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/delay.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/serial_8250.h>
#include <linux/pm_runtime.h>
OMAP2+: PM/serial: hold console semaphore while OMAP UARTs are disabled The console semaphore must be held while the OMAP UART devices are disabled, lest a console write cause an ARM abort (and a kernel crash) when the underlying console device is inaccessible. These crashes only occur when the console is on one of the OMAP internal serial ports. While this problem has been latent in the PM idle loop for some time, the crash was not triggerable with an unmodified kernel until commit 6f251e9db1093c187addc309b5f2f7fe3efd2995 ("OMAP: UART: omap_device conversions, remove implicit 8520 assumptions"). After this patch, a console write often occurs after the console UART has been disabled in the idle loop, crashing the system. Several users have encountered this bug: http://www.mail-archive.com/linux-omap@vger.kernel.org/msg38396.html http://www.mail-archive.com/linux-omap@vger.kernel.org/msg36602.html The same commit also introduced new code that disabled the UARTs during init, in omap_serial_init_port(). The kernel will also crash in this code when earlyconsole and extra debugging is enabled: http://www.mail-archive.com/linux-omap@vger.kernel.org/msg36411.html The minimal fix for the -rc series is to hold the console semaphore while the OMAP UARTs are disabled. This is a somewhat overbroad fix, since the console may not be located on an OMAP UART, as is the case with the GPMC UART on Zoom3. While it is technically possible to determine which devices the console or earlyconsole is actually running on, it is not a trivial problem to solve, and the code to do so is not really appropriate for the -rc series. The right long-term fix is to ensure that no code outside of the OMAP serial driver can disable an OMAP UART. As I understand it, code to implement this is under development by TI. This patch is a collaboration between Paul Walmsley <paul@pwsan.com> and Tony Lindgren <tony@atomide.com>. Thanks to Ming Lei <tom.leiming@gmail.com> and Pramod <pramod.gurav@ti.com> for their feedback on earlier versions of this patch. Signed-off-by: Paul Walmsley <paul@pwsan.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Acked-by: Kevin Hilman <khilman@deeprootsystems.com> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Pramod <pramod.gurav@ti.com> Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Cc: Jean Pihet <jean.pihet@newoldbits.com> Cc: Govindraj.R <govindraj.raja@ti.com>
2010-11-24 16:49:05 -07:00
#include <linux/console.h>
#ifdef CONFIG_SERIAL_OMAP
#include <plat/omap-serial.h>
#endif
#include <plat/common.h>
#include <plat/board.h>
#include <plat/clock.h>
#include <plat/dma.h>
#include <plat/omap_hwmod.h>
#include <plat/omap_device.h>
#include "prm2xxx_3xxx.h"
#include "pm.h"
#include "cm2xxx_3xxx.h"
#include "prm-regbits-34xx.h"
#include "control.h"
#include "mux.h"
#define UART_OMAP_NO_EMPTY_FIFO_READ_IP_REV 0x52
#define UART_OMAP_WER 0x17 /* Wake-up enable register */
#define UART_ERRATA_FIFO_FULL_ABORT (0x1 << 0)
#define UART_ERRATA_i202_MDR1_ACCESS (0x1 << 1)
/*
* NOTE: By default the serial timeout is disabled as it causes lost characters
* over the serial ports. This means that the UART clocks will stay on until
* disabled via sysfs. This also causes that any deeper omap sleep states are
* blocked.
*/
#define DEFAULT_TIMEOUT 0
#define MAX_UART_HWMOD_NAME_LEN 16
struct omap_uart_state {
int num;
int can_sleep;
struct timer_list timer;
u32 timeout;
void __iomem *wk_st;
void __iomem *wk_en;
u32 wk_mask;
u32 padconf;
u32 dma_enabled;
struct clk *ick;
struct clk *fck;
int clocked;
int irq;
int regshift;
int irqflags;
void __iomem *membase;
resource_size_t mapbase;
struct list_head node;
struct omap_hwmod *oh;
struct platform_device *pdev;
u32 errata;
#if defined(CONFIG_ARCH_OMAP3) && defined(CONFIG_PM)
int context_valid;
/* Registers to be saved/restored for OFF-mode */
u16 dll;
u16 dlh;
u16 ier;
u16 sysc;
u16 scr;
u16 wer;
u16 mcr;
#endif
};
static LIST_HEAD(uart_list);
static u8 num_uarts;
static int uart_idle_hwmod(struct omap_device *od)
{
omap_hwmod_idle(od->hwmods[0]);
return 0;
}
static int uart_enable_hwmod(struct omap_device *od)
{
omap_hwmod_enable(od->hwmods[0]);
return 0;
}
static struct omap_device_pm_latency omap_uart_latency[] = {
{
.deactivate_func = uart_idle_hwmod,
.activate_func = uart_enable_hwmod,
.flags = OMAP_DEVICE_LATENCY_AUTO_ADJUST,
},
};
static inline unsigned int __serial_read_reg(struct uart_port *up,
int offset)
{
offset <<= up->regshift;
return (unsigned int)__raw_readb(up->membase + offset);
}
static inline unsigned int serial_read_reg(struct omap_uart_state *uart,
int offset)
{
offset <<= uart->regshift;
return (unsigned int)__raw_readb(uart->membase + offset);
}
static inline void __serial_write_reg(struct uart_port *up, int offset,
int value)
{
offset <<= up->regshift;
__raw_writeb(value, up->membase + offset);
}
static inline void serial_write_reg(struct omap_uart_state *uart, int offset,
int value)
{
offset <<= uart->regshift;
__raw_writeb(value, uart->membase + offset);
}
/*
* Internal UARTs need to be initialized for the 8250 autoconfig to work
* properly. Note that the TX watermark initialization may not be needed
* once the 8250.c watermark handling code is merged.
*/
static inline void __init omap_uart_reset(struct omap_uart_state *uart)
{
serial_write_reg(uart, UART_OMAP_MDR1, UART_OMAP_MDR1_DISABLE);
serial_write_reg(uart, UART_OMAP_SCR, 0x08);
serial_write_reg(uart, UART_OMAP_MDR1, UART_OMAP_MDR1_16X_MODE);
}
#if defined(CONFIG_PM) && defined(CONFIG_ARCH_OMAP3)
/*
* Work Around for Errata i202 (3430 - 1.12, 3630 - 1.6)
* The access to uart register after MDR1 Access
* causes UART to corrupt data.
*
* Need a delay =
* 5 L4 clock cycles + 5 UART functional clock cycle (@48MHz = ~0.2uS)
* give 10 times as much
*/
static void omap_uart_mdr1_errataset(struct omap_uart_state *uart, u8 mdr1_val,
u8 fcr_val)
{
u8 timeout = 255;
serial_write_reg(uart, UART_OMAP_MDR1, mdr1_val);
udelay(2);
serial_write_reg(uart, UART_FCR, fcr_val | UART_FCR_CLEAR_XMIT |
UART_FCR_CLEAR_RCVR);
/*
* Wait for FIFO to empty: when empty, RX_FIFO_E bit is 0 and
* TX_FIFO_E bit is 1.
*/
while (UART_LSR_THRE != (serial_read_reg(uart, UART_LSR) &
(UART_LSR_THRE | UART_LSR_DR))) {
timeout--;
if (!timeout) {
/* Should *never* happen. we warn and carry on */
dev_crit(&uart->pdev->dev, "Errata i202: timedout %x\n",
serial_read_reg(uart, UART_LSR));
break;
}
udelay(1);
}
}
static void omap_uart_save_context(struct omap_uart_state *uart)
{
u16 lcr = 0;
if (!enable_off_mode)
return;
lcr = serial_read_reg(uart, UART_LCR);
serial_write_reg(uart, UART_LCR, UART_LCR_CONF_MODE_B);
uart->dll = serial_read_reg(uart, UART_DLL);
uart->dlh = serial_read_reg(uart, UART_DLM);
serial_write_reg(uart, UART_LCR, lcr);
uart->ier = serial_read_reg(uart, UART_IER);
uart->sysc = serial_read_reg(uart, UART_OMAP_SYSC);
uart->scr = serial_read_reg(uart, UART_OMAP_SCR);
uart->wer = serial_read_reg(uart, UART_OMAP_WER);
serial_write_reg(uart, UART_LCR, UART_LCR_CONF_MODE_A);
uart->mcr = serial_read_reg(uart, UART_MCR);
serial_write_reg(uart, UART_LCR, lcr);
uart->context_valid = 1;
}
static void omap_uart_restore_context(struct omap_uart_state *uart)
{
u16 efr = 0;
if (!enable_off_mode)
return;
if (!uart->context_valid)
return;
uart->context_valid = 0;
if (uart->errata & UART_ERRATA_i202_MDR1_ACCESS)
omap_uart_mdr1_errataset(uart, UART_OMAP_MDR1_DISABLE, 0xA0);
else
serial_write_reg(uart, UART_OMAP_MDR1, UART_OMAP_MDR1_DISABLE);
serial_write_reg(uart, UART_LCR, UART_LCR_CONF_MODE_B);
efr = serial_read_reg(uart, UART_EFR);
serial_write_reg(uart, UART_EFR, UART_EFR_ECB);
serial_write_reg(uart, UART_LCR, 0x0); /* Operational mode */
serial_write_reg(uart, UART_IER, 0x0);
serial_write_reg(uart, UART_LCR, UART_LCR_CONF_MODE_B);
serial_write_reg(uart, UART_DLL, uart->dll);
serial_write_reg(uart, UART_DLM, uart->dlh);
serial_write_reg(uart, UART_LCR, 0x0); /* Operational mode */
serial_write_reg(uart, UART_IER, uart->ier);
serial_write_reg(uart, UART_LCR, UART_LCR_CONF_MODE_A);
serial_write_reg(uart, UART_MCR, uart->mcr);
serial_write_reg(uart, UART_LCR, UART_LCR_CONF_MODE_B);
serial_write_reg(uart, UART_EFR, efr);
serial_write_reg(uart, UART_LCR, UART_LCR_WLEN8);
serial_write_reg(uart, UART_OMAP_SCR, uart->scr);
serial_write_reg(uart, UART_OMAP_WER, uart->wer);
serial_write_reg(uart, UART_OMAP_SYSC, uart->sysc);
if (uart->errata & UART_ERRATA_i202_MDR1_ACCESS)
omap_uart_mdr1_errataset(uart, UART_OMAP_MDR1_16X_MODE, 0xA1);
else
/* UART 16x mode */
serial_write_reg(uart, UART_OMAP_MDR1,
UART_OMAP_MDR1_16X_MODE);
}
#else
static inline void omap_uart_save_context(struct omap_uart_state *uart) {}
static inline void omap_uart_restore_context(struct omap_uart_state *uart) {}
#endif /* CONFIG_PM && CONFIG_ARCH_OMAP3 */
static inline void omap_uart_enable_clocks(struct omap_uart_state *uart)
{
if (uart->clocked)
return;
omap_device_enable(uart->pdev);
uart->clocked = 1;
omap_uart_restore_context(uart);
}
#ifdef CONFIG_PM
static inline void omap_uart_disable_clocks(struct omap_uart_state *uart)
{
if (!uart->clocked)
return;
omap_uart_save_context(uart);
uart->clocked = 0;
omap_device_idle(uart->pdev);
}
static void omap_uart_enable_wakeup(struct omap_uart_state *uart)
{
/* Set wake-enable bit */
if (uart->wk_en && uart->wk_mask) {
u32 v = __raw_readl(uart->wk_en);
v |= uart->wk_mask;
__raw_writel(v, uart->wk_en);
}
/* Ensure IOPAD wake-enables are set */
if (cpu_is_omap34xx() && uart->padconf) {
u16 v = omap_ctrl_readw(uart->padconf);
v |= OMAP3_PADCONF_WAKEUPENABLE0;
omap_ctrl_writew(v, uart->padconf);
}
}
static void omap_uart_disable_wakeup(struct omap_uart_state *uart)
{
/* Clear wake-enable bit */
if (uart->wk_en && uart->wk_mask) {
u32 v = __raw_readl(uart->wk_en);
v &= ~uart->wk_mask;
__raw_writel(v, uart->wk_en);
}
/* Ensure IOPAD wake-enables are cleared */
if (cpu_is_omap34xx() && uart->padconf) {
u16 v = omap_ctrl_readw(uart->padconf);
v &= ~OMAP3_PADCONF_WAKEUPENABLE0;
omap_ctrl_writew(v, uart->padconf);
}
}
static void omap_uart_smart_idle_enable(struct omap_uart_state *uart,
int enable)
{
u8 idlemode;
if (enable) {
/**
* Errata 2.15: [UART]:Cannot Acknowledge Idle Requests
* in Smartidle Mode When Configured for DMA Operations.
*/
if (uart->dma_enabled)
idlemode = HWMOD_IDLEMODE_FORCE;
else
idlemode = HWMOD_IDLEMODE_SMART;
} else {
idlemode = HWMOD_IDLEMODE_NO;
}
omap_hwmod_set_slave_idlemode(uart->oh, idlemode);
}
static void omap_uart_block_sleep(struct omap_uart_state *uart)
{
omap_uart_enable_clocks(uart);
omap_uart_smart_idle_enable(uart, 0);
uart->can_sleep = 0;
if (uart->timeout)
mod_timer(&uart->timer, jiffies + uart->timeout);
else
del_timer(&uart->timer);
}
static void omap_uart_allow_sleep(struct omap_uart_state *uart)
{
if (device_may_wakeup(&uart->pdev->dev))
omap_uart_enable_wakeup(uart);
else
omap_uart_disable_wakeup(uart);
if (!uart->clocked)
return;
omap_uart_smart_idle_enable(uart, 1);
uart->can_sleep = 1;
del_timer(&uart->timer);
}
static void omap_uart_idle_timer(unsigned long data)
{
struct omap_uart_state *uart = (struct omap_uart_state *)data;
omap_uart_allow_sleep(uart);
}
void omap_uart_prepare_idle(int num)
{
struct omap_uart_state *uart;
list_for_each_entry(uart, &uart_list, node) {
if (num == uart->num && uart->can_sleep) {
omap_uart_disable_clocks(uart);
return;
}
}
}
void omap_uart_resume_idle(int num)
{
struct omap_uart_state *uart;
list_for_each_entry(uart, &uart_list, node) {
if (num == uart->num && uart->can_sleep) {
omap_uart_enable_clocks(uart);
/* Check for IO pad wakeup */
if (cpu_is_omap34xx() && uart->padconf) {
u16 p = omap_ctrl_readw(uart->padconf);
if (p & OMAP3_PADCONF_WAKEUPEVENT0)
omap_uart_block_sleep(uart);
}
/* Check for normal UART wakeup */
if (__raw_readl(uart->wk_st) & uart->wk_mask)
omap_uart_block_sleep(uart);
return;
}
}
}
void omap_uart_prepare_suspend(void)
{
struct omap_uart_state *uart;
list_for_each_entry(uart, &uart_list, node) {
omap_uart_allow_sleep(uart);
}
}
int omap_uart_can_sleep(void)
{
struct omap_uart_state *uart;
int can_sleep = 1;
list_for_each_entry(uart, &uart_list, node) {
if (!uart->clocked)
continue;
if (!uart->can_sleep) {
can_sleep = 0;
continue;
}
/* This UART can now safely sleep. */
omap_uart_allow_sleep(uart);
}
return can_sleep;
}
/**
* omap_uart_interrupt()
*
* This handler is used only to detect that *any* UART interrupt has
* occurred. It does _nothing_ to handle the interrupt. Rather,
* any UART interrupt will trigger the inactivity timer so the
* UART will not idle or sleep for its timeout period.
*
**/
/* static int first_interrupt; */
static irqreturn_t omap_uart_interrupt(int irq, void *dev_id)
{
struct omap_uart_state *uart = dev_id;
omap_uart_block_sleep(uart);
return IRQ_NONE;
}
static void omap_uart_idle_init(struct omap_uart_state *uart)
{
int ret;
uart->can_sleep = 0;
uart->timeout = DEFAULT_TIMEOUT;
setup_timer(&uart->timer, omap_uart_idle_timer,
(unsigned long) uart);
if (uart->timeout)
mod_timer(&uart->timer, jiffies + uart->timeout);
omap_uart_smart_idle_enable(uart, 0);
if (cpu_is_omap34xx() && !cpu_is_ti816x()) {
u32 mod = (uart->num > 1) ? OMAP3430_PER_MOD : CORE_MOD;
u32 wk_mask = 0;
u32 padconf = 0;
/* XXX These PRM accesses do not belong here */
uart->wk_en = OMAP34XX_PRM_REGADDR(mod, PM_WKEN1);
uart->wk_st = OMAP34XX_PRM_REGADDR(mod, PM_WKST1);
switch (uart->num) {
case 0:
wk_mask = OMAP3430_ST_UART1_MASK;
padconf = 0x182;
break;
case 1:
wk_mask = OMAP3430_ST_UART2_MASK;
padconf = 0x17a;
break;
case 2:
wk_mask = OMAP3430_ST_UART3_MASK;
padconf = 0x19e;
break;
case 3:
wk_mask = OMAP3630_ST_UART4_MASK;
padconf = 0x0d2;
break;
}
uart->wk_mask = wk_mask;
uart->padconf = padconf;
} else if (cpu_is_omap24xx()) {
u32 wk_mask = 0;
u32 wk_en = PM_WKEN1, wk_st = PM_WKST1;
switch (uart->num) {
case 0:
wk_mask = OMAP24XX_ST_UART1_MASK;
break;
case 1:
wk_mask = OMAP24XX_ST_UART2_MASK;
break;
case 2:
wk_en = OMAP24XX_PM_WKEN2;
wk_st = OMAP24XX_PM_WKST2;
wk_mask = OMAP24XX_ST_UART3_MASK;
break;
}
uart->wk_mask = wk_mask;
if (cpu_is_omap2430()) {
uart->wk_en = OMAP2430_PRM_REGADDR(CORE_MOD, wk_en);
uart->wk_st = OMAP2430_PRM_REGADDR(CORE_MOD, wk_st);
} else if (cpu_is_omap2420()) {
uart->wk_en = OMAP2420_PRM_REGADDR(CORE_MOD, wk_en);
uart->wk_st = OMAP2420_PRM_REGADDR(CORE_MOD, wk_st);
}
} else {
uart->wk_en = NULL;
uart->wk_st = NULL;
uart->wk_mask = 0;
uart->padconf = 0;
}
uart->irqflags |= IRQF_SHARED;
ret = request_threaded_irq(uart->irq, NULL, omap_uart_interrupt,
IRQF_SHARED, "serial idle", (void *)uart);
WARN_ON(ret);
}
void omap_uart_enable_irqs(int enable)
{
int ret;
struct omap_uart_state *uart;
list_for_each_entry(uart, &uart_list, node) {
if (enable) {
pm_runtime_put_sync(&uart->pdev->dev);
ret = request_threaded_irq(uart->irq, NULL,
omap_uart_interrupt,
IRQF_SHARED,
"serial idle",
(void *)uart);
} else {
pm_runtime_get_noresume(&uart->pdev->dev);
free_irq(uart->irq, (void *)uart);
}
}
}
static ssize_t sleep_timeout_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct platform_device *pdev = to_platform_device(dev);
struct omap_device *odev = to_omap_device(pdev);
struct omap_uart_state *uart = odev->hwmods[0]->dev_attr;
return sprintf(buf, "%u\n", uart->timeout / HZ);
}
static ssize_t sleep_timeout_store(struct device *dev,
struct device_attribute *attr,
const char *buf, size_t n)
{
struct platform_device *pdev = to_platform_device(dev);
struct omap_device *odev = to_omap_device(pdev);
struct omap_uart_state *uart = odev->hwmods[0]->dev_attr;
unsigned int value;
if (sscanf(buf, "%u", &value) != 1) {
dev_err(dev, "sleep_timeout_store: Invalid value\n");
return -EINVAL;
}
uart->timeout = value * HZ;
if (uart->timeout)
mod_timer(&uart->timer, jiffies + uart->timeout);
else
/* A zero value means disable timeout feature */
omap_uart_block_sleep(uart);
return n;
}
static DEVICE_ATTR(sleep_timeout, 0644, sleep_timeout_show,
sleep_timeout_store);
#define DEV_CREATE_FILE(dev, attr) WARN_ON(device_create_file(dev, attr))
#else
static inline void omap_uart_idle_init(struct omap_uart_state *uart) {}
omap: serial: Fix the boot-up crash/reboot without CONFIG_PM The omap2plus_defconfig doesn't boot up when built with CONFIG_PM disabled on the latest linux-omap master. Below are the observations 1. OMAP3 reboots in the middle of boot -------------------------------------------------- [ 0.000000] Calibrating delay loop... 494.72 BogoMIPS (lpj=1933312) [ 0.000000] pid_max: default: 32768 minimum: 301 [ 0.000000] Security Framework initialized [ 0.000000] Mount-cache hash table entries: 512 [ 0.000000] CPU: Testing write buffer coherency: ok [ 0.000000] Brought up 1 CPUs [ 0.000000] SMP: Total of 1 processors activated (494.72 BogoMIPS). [ 0.000000] regulator: core version 0.5 [ 0.000000] NET: Registered protocol family 16 U-Boot 1.1.4 (Feb 11 2009 - 16:10:23) OMAP3430-GP rev 2, CPU-OPP2 L3-165MHz TI 3430SDP 1.0 Version + mDDR (Boot NOR) DRAM: 128 MB Flash: 128 MB NAND:128 MiB -------------------------------------------------- 2. OMAP4 does a kernel PANIC ------------------------------------- [ 0.000000] Calibrating delay loop... 1195.29 BogoMIPS (lpj=4669440) [ 0.000000] pid_max: default: 32768 minimum: 301 [ 0.000000] Security Framework initialized [ 0.000000] Mount-cache hash table entries: 512 [ 0.000000] CPU: Testing write buffer coherency: ok [ 0.000000] L310 cache controller enabled [ 0.000000] l2x0: 16 ways, CACHE_ID 0x410000c2, AUX_CTRL 0x0e050000 [ 0.000000] CPU1: Booted secondary processor [ 0.000000] Brought up 2 CPUs [ 0.000000] SMP: Total of 2 processors activated (2395.78 BogoMIPS). [ 0.000000] regulator: core version 0.5 [ 0.000000] NET: Registered protocol family 16 [ 0.000000] mux: Could not set signal i2c2_scl.i2c2_scl [ 0.000000] mux: Could not set signal i2c2_sda.i2c2_sda [ 0.000000] mux: Could not set signal i2c3_scl.i2c3_scl [ 0.000000] mux: Could not set signal i2c3_sda.i2c3_sda [ 0.000000] mux: Could not set signal i2c4_scl.i2c4_scl [ 0.000000] mux: Could not set signal i2c4_sda.i2c4_sda ------------------------------------- This is happening because 'omap_serial_init()' is hanging in the boot. On OMAP3 the watchdog is generating reboot because devices_init doesn't happens where as on OMAP4 it just hangs without reboot. The uart clock is not getting enabled after omap_device_idle as part of omap_serial_init. The omap_device_idle(will disable the clock) then omap_uart_block_sleep() should enable clock back disabled during the boot up phase. But omap_uart_block_sleep() stuffed version is binded only under CONFIG_PM and other version is just empty. Hence it is not enabling clock back as expected This patch adds uart clock enable code to omap_uart_block_sleep() function built with CONFIG_PM disabled. Thanks to Charulatha and Govindraj for their help on this debug. Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com> Signed-off-by: Charulatha V <charu@ti.com> Signed-off-by: Govindraj.R <govindraj.raja@ti.com> Acked-by: Kevin Hilman <khilman@deeprootsystems.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
2010-10-11 05:05:18 -06:00
static void omap_uart_block_sleep(struct omap_uart_state *uart)
{
/* Needed to enable UART clocks when built without CONFIG_PM */
omap_uart_enable_clocks(uart);
}
#define DEV_CREATE_FILE(dev, attr)
#endif /* CONFIG_PM */
#ifndef CONFIG_SERIAL_OMAP
/*
* Override the default 8250 read handler: mem_serial_in()
* Empty RX fifo read causes an abort on omap3630 and omap4
* This function makes sure that an empty rx fifo is not read on these silicons
* (OMAP1/2/3430 are not affected)
*/
static unsigned int serial_in_override(struct uart_port *up, int offset)
{
if (UART_RX == offset) {
unsigned int lsr;
lsr = __serial_read_reg(up, UART_LSR);
if (!(lsr & UART_LSR_DR))
return -EPERM;
}
return __serial_read_reg(up, offset);
}
static void serial_out_override(struct uart_port *up, int offset, int value)
{
unsigned int status, tmout = 10000;
status = __serial_read_reg(up, UART_LSR);
while (!(status & UART_LSR_THRE)) {
/* Wait up to 10ms for the character(s) to be sent. */
if (--tmout == 0)
break;
udelay(1);
status = __serial_read_reg(up, UART_LSR);
}
__serial_write_reg(up, offset, value);
}
#endif
static int __init omap_serial_early_init(void)
{
int i = 0;
do {
char oh_name[MAX_UART_HWMOD_NAME_LEN];
struct omap_hwmod *oh;
struct omap_uart_state *uart;
snprintf(oh_name, MAX_UART_HWMOD_NAME_LEN,
"uart%d", i + 1);
oh = omap_hwmod_lookup(oh_name);
if (!oh)
break;
uart = kzalloc(sizeof(struct omap_uart_state), GFP_KERNEL);
if (WARN_ON(!uart))
return -ENODEV;
uart->oh = oh;
uart->num = i++;
list_add_tail(&uart->node, &uart_list);
num_uarts++;
/*
* NOTE: omap_hwmod_setup*() has not yet been called,
* so no hwmod functions will work yet.
*/
/*
* During UART early init, device need to be probed
* to determine SoC specific init before omap_device
* is ready. Therefore, don't allow idle here
*/
uart->oh->flags |= HWMOD_INIT_NO_IDLE | HWMOD_INIT_NO_RESET;
} while (1);
return 0;
}
core_initcall(omap_serial_early_init);
/**
* omap_serial_init_port() - initialize single serial port
* @bdata: port specific board data pointer
*
* This function initialies serial driver for given port only.
* Platforms can call this function instead of omap_serial_init()
* if they don't plan to use all available UARTs as serial ports.
*
* Don't mix calls to omap_serial_init_port() and omap_serial_init(),
* use only one of the two.
*/
void __init omap_serial_init_port(struct omap_board_data *bdata)
{
struct omap_uart_state *uart;
struct omap_hwmod *oh;
struct omap_device *od;
void *pdata = NULL;
u32 pdata_size = 0;
char *name;
#ifndef CONFIG_SERIAL_OMAP
struct plat_serial8250_port ports[2] = {
{},
{.flags = 0},
};
struct plat_serial8250_port *p = &ports[0];
#else
struct omap_uart_port_info omap_up;
#endif
if (WARN_ON(!bdata))
return;
if (WARN_ON(bdata->id < 0))
return;
if (WARN_ON(bdata->id >= num_uarts))
return;
list_for_each_entry(uart, &uart_list, node)
if (bdata->id == uart->num)
break;
OMAP3: serial - fix bug introduced in Commit f62349ee9788b1d94c55eb6c291d74a1f69bdd9e had side effect that causes kernel to oops when we are suspending to ram: # echo mem > /sys/power/state WARNING: at kernel/irq/manage.c:858 __free_irq+0x90/0x174() Trying to free already-free IRQ 72 Modules linked in: Backtrace: [<c00328d0>] (dump_backtrace+0x0/0x110) from [<c0347298>] (dump_stack+0x18/0x1c) r7:dfd4be08 r6:c009505c r5:c03fbfd1 r4:0000035a [<c0347280>] (dump_stack+0x0/0x1c) from [<c005a408>] (warn_slowpath_common+0x50/0x68) [<c005a3b8>] (warn_slowpath_common+0x0/0x68) from [<c005a46c>] (warn_slowpath_fmt+0x30) r7:c0474afc r6:00000048 r5:00000000 r4:c0474ac0 [<c005a43c>] (warn_slowpath_fmt+0x0/0x38) from [<c009505c>] (__free_irq+0x90/0x174) r3:00000048 r2:c03fc0ef [<c0094fcc>] (__free_irq+0x0/0x174) from [<c0095184>] (free_irq+0x44/0x64) [<c0095140>] (free_irq+0x0/0x64) from [<c0038100>] (omap_uart_enable_irqs+0x4c/0x90) r7:c034d58c r6:00000003 r5:00000000 r4:c0463028 [<c00380b4>] (omap_uart_enable_irqs+0x0/0x90) from [<c003d8f8>] (omap3_pm_begin+0x1c/0) r5:00000003 r4:00000000 [<c003d8dc>] (omap3_pm_begin+0x0/0x28) from [<c008d008>] (suspend_devices_and_enter+0x) [<c008cfd8>] (suspend_devices_and_enter+0x0/0x1dc) from [<c008d29c>] (enter_state+0xe8) r5:c03f7f46 r4:00000000 [<c008d1b4>] (enter_state+0x0/0x140) from [<c008c8e0>] (state_store+0x9c/0xc4) r7:c034d58c r6:00000003 r5:00000003 r4:c03f7f46 [<c008c844>] (state_store+0x0/0xc4) from [<c01cb2dc>] (kobj_attr_store+0x20/0x24) [<c01cb2bc>] (kobj_attr_store+0x0/0x24) from [<c0119420>] (sysfs_write_file+0x114/0x14) [<c011930c>] (sysfs_write_file+0x0/0x148) from [<c00cb298>] (vfs_write+0xb8/0x164) [<c00cb1e0>] (vfs_write+0x0/0x164) from [<c00cb408>] (sys_write+0x44/0x70) r8:4001f000 r7:00000004 r6:df81bd00 r5:00000000 r4:00000000 [<c00cb3c4>] (sys_write+0x0/0x70) from [<c002f040>] (ret_fast_syscall+0x0/0x38) r8:c002f204 r7:00000004 r6:401fa5e8 r5:4001f000 r4:00000004 This is due the fact that uart_list list was populated in omap_serial_early_init() and omap_uart_enable_irqs() went through this list even when serial idle wasn't enabled for all uarts. This patch moves the code that populates the uart_list and enables uart clocks into omap_serial_init_port(). Signed-off-by: Mika Westerberg <ext-mika.1.westerberg@nokia.com> Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com> Signed-off-by: Tony Lindgren <tony@atomide.com>
2009-12-14 06:59:18 -07:00
oh = uart->oh;
uart->dma_enabled = 0;
#ifndef CONFIG_SERIAL_OMAP
name = "serial8250";
/*
* !! 8250 driver does not use standard IORESOURCE* It
* has it's own custom pdata that can be taken from
* the hwmod resource data. But, this needs to be
* done after the build.
*
* ?? does it have to be done before the register ??
* YES, because platform_device_data_add() copies
* pdata, it does not use a pointer.
*/
p->flags = UPF_BOOT_AUTOCONF;
p->iotype = UPIO_MEM;
p->regshift = 2;
p->uartclk = OMAP24XX_BASE_BAUD * 16;
p->irq = oh->mpu_irqs[0].irq;
p->mapbase = oh->slaves[0]->addr->pa_start;
p->membase = omap_hwmod_get_mpu_rt_va(oh);
p->irqflags = IRQF_SHARED;
p->private_data = uart;
/*
* omap44xx, ti816x: Never read empty UART fifo
* omap3xxx: Never read empty UART fifo on UARTs
* with IP rev >=0x52
*/
uart->regshift = p->regshift;
uart->membase = p->membase;
if (cpu_is_omap44xx() || cpu_is_ti816x())
uart->errata |= UART_ERRATA_FIFO_FULL_ABORT;
else if ((serial_read_reg(uart, UART_OMAP_MVER) & 0xFF)
>= UART_OMAP_NO_EMPTY_FIFO_READ_IP_REV)
uart->errata |= UART_ERRATA_FIFO_FULL_ABORT;
if (uart->errata & UART_ERRATA_FIFO_FULL_ABORT) {
p->serial_in = serial_in_override;
p->serial_out = serial_out_override;
}
pdata = &ports[0];
pdata_size = 2 * sizeof(struct plat_serial8250_port);
#else
name = DRIVER_NAME;
omap_up.dma_enabled = uart->dma_enabled;
omap_up.uartclk = OMAP24XX_BASE_BAUD * 16;
omap_up.mapbase = oh->slaves[0]->addr->pa_start;
omap_up.membase = omap_hwmod_get_mpu_rt_va(oh);
omap_up.irqflags = IRQF_SHARED;
omap_up.flags = UPF_BOOT_AUTOCONF | UPF_SHARE_IRQ;
pdata = &omap_up;
pdata_size = sizeof(struct omap_uart_port_info);
#endif
if (WARN_ON(!oh))
return;
od = omap_device_build(name, uart->num, oh, pdata, pdata_size,
omap_uart_latency,
ARRAY_SIZE(omap_uart_latency), false);
WARN(IS_ERR(od), "Could not build omap_device for %s: %s.\n",
name, oh->name);
omap_device_disable_idle_on_suspend(od);
oh->mux = omap_hwmod_mux_init(bdata->pads, bdata->pads_cnt);
uart->irq = oh->mpu_irqs[0].irq;
uart->regshift = 2;
uart->mapbase = oh->slaves[0]->addr->pa_start;
uart->membase = omap_hwmod_get_mpu_rt_va(oh);
uart->pdev = &od->pdev;
oh->dev_attr = uart;
console_lock(); /* in case the earlycon is on the UART */
OMAP2+: PM/serial: hold console semaphore while OMAP UARTs are disabled The console semaphore must be held while the OMAP UART devices are disabled, lest a console write cause an ARM abort (and a kernel crash) when the underlying console device is inaccessible. These crashes only occur when the console is on one of the OMAP internal serial ports. While this problem has been latent in the PM idle loop for some time, the crash was not triggerable with an unmodified kernel until commit 6f251e9db1093c187addc309b5f2f7fe3efd2995 ("OMAP: UART: omap_device conversions, remove implicit 8520 assumptions"). After this patch, a console write often occurs after the console UART has been disabled in the idle loop, crashing the system. Several users have encountered this bug: http://www.mail-archive.com/linux-omap@vger.kernel.org/msg38396.html http://www.mail-archive.com/linux-omap@vger.kernel.org/msg36602.html The same commit also introduced new code that disabled the UARTs during init, in omap_serial_init_port(). The kernel will also crash in this code when earlyconsole and extra debugging is enabled: http://www.mail-archive.com/linux-omap@vger.kernel.org/msg36411.html The minimal fix for the -rc series is to hold the console semaphore while the OMAP UARTs are disabled. This is a somewhat overbroad fix, since the console may not be located on an OMAP UART, as is the case with the GPMC UART on Zoom3. While it is technically possible to determine which devices the console or earlyconsole is actually running on, it is not a trivial problem to solve, and the code to do so is not really appropriate for the -rc series. The right long-term fix is to ensure that no code outside of the OMAP serial driver can disable an OMAP UART. As I understand it, code to implement this is under development by TI. This patch is a collaboration between Paul Walmsley <paul@pwsan.com> and Tony Lindgren <tony@atomide.com>. Thanks to Ming Lei <tom.leiming@gmail.com> and Pramod <pramod.gurav@ti.com> for their feedback on earlier versions of this patch. Signed-off-by: Paul Walmsley <paul@pwsan.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Acked-by: Kevin Hilman <khilman@deeprootsystems.com> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Pramod <pramod.gurav@ti.com> Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Cc: Jean Pihet <jean.pihet@newoldbits.com> Cc: Govindraj.R <govindraj.raja@ti.com>
2010-11-24 16:49:05 -07:00
/*
* Because of early UART probing, UART did not get idled
* on init. Now that omap_device is ready, ensure full idle
* before doing omap_device_enable().
*/
omap_hwmod_idle(uart->oh);
omap_device_enable(uart->pdev);
omap_uart_idle_init(uart);
omap_uart_reset(uart);
omap_hwmod_enable_wakeup(uart->oh);
omap_device_idle(uart->pdev);
/*
* Need to block sleep long enough for interrupt driven
* driver to start. Console driver is in polling mode
* so device needs to be kept enabled while polling driver
* is in use.
*/
if (uart->timeout)
uart->timeout = (30 * HZ);
omap_uart_block_sleep(uart);
uart->timeout = DEFAULT_TIMEOUT;
console_unlock();
OMAP2+: PM/serial: hold console semaphore while OMAP UARTs are disabled The console semaphore must be held while the OMAP UART devices are disabled, lest a console write cause an ARM abort (and a kernel crash) when the underlying console device is inaccessible. These crashes only occur when the console is on one of the OMAP internal serial ports. While this problem has been latent in the PM idle loop for some time, the crash was not triggerable with an unmodified kernel until commit 6f251e9db1093c187addc309b5f2f7fe3efd2995 ("OMAP: UART: omap_device conversions, remove implicit 8520 assumptions"). After this patch, a console write often occurs after the console UART has been disabled in the idle loop, crashing the system. Several users have encountered this bug: http://www.mail-archive.com/linux-omap@vger.kernel.org/msg38396.html http://www.mail-archive.com/linux-omap@vger.kernel.org/msg36602.html The same commit also introduced new code that disabled the UARTs during init, in omap_serial_init_port(). The kernel will also crash in this code when earlyconsole and extra debugging is enabled: http://www.mail-archive.com/linux-omap@vger.kernel.org/msg36411.html The minimal fix for the -rc series is to hold the console semaphore while the OMAP UARTs are disabled. This is a somewhat overbroad fix, since the console may not be located on an OMAP UART, as is the case with the GPMC UART on Zoom3. While it is technically possible to determine which devices the console or earlyconsole is actually running on, it is not a trivial problem to solve, and the code to do so is not really appropriate for the -rc series. The right long-term fix is to ensure that no code outside of the OMAP serial driver can disable an OMAP UART. As I understand it, code to implement this is under development by TI. This patch is a collaboration between Paul Walmsley <paul@pwsan.com> and Tony Lindgren <tony@atomide.com>. Thanks to Ming Lei <tom.leiming@gmail.com> and Pramod <pramod.gurav@ti.com> for their feedback on earlier versions of this patch. Signed-off-by: Paul Walmsley <paul@pwsan.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Acked-by: Kevin Hilman <khilman@deeprootsystems.com> Cc: Ming Lei <tom.leiming@gmail.com> Cc: Pramod <pramod.gurav@ti.com> Cc: Thomas Petazzoni <thomas.petazzoni@free-electrons.com> Cc: Jean Pihet <jean.pihet@newoldbits.com> Cc: Govindraj.R <govindraj.raja@ti.com>
2010-11-24 16:49:05 -07:00
if ((cpu_is_omap34xx() && uart->padconf) ||
(uart->wk_en && uart->wk_mask)) {
device_init_wakeup(&od->pdev.dev, true);
DEV_CREATE_FILE(&od->pdev.dev, &dev_attr_sleep_timeout);
}
/* Enable the MDR1 errata for OMAP3 */
if (cpu_is_omap34xx() && !cpu_is_ti816x())
uart->errata |= UART_ERRATA_i202_MDR1_ACCESS;
}
/**
* omap_serial_init() - initialize all supported serial ports
*
* Initializes all available UARTs as serial ports. Platforms
* can call this function when they want to have default behaviour
* for serial ports (e.g initialize them all as serial ports).
*/
void __init omap_serial_init(void)
{
struct omap_uart_state *uart;
struct omap_board_data bdata;
list_for_each_entry(uart, &uart_list, node) {
bdata.id = uart->num;
bdata.flags = 0;
bdata.pads = NULL;
bdata.pads_cnt = 0;
omap_serial_init_port(&bdata);
}
}