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linux-next/arch/arm/mach-omap2/pm24xx.c
Paul Walmsley 0d8e2d0dad 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
6f251e9db1 ("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 16:14:30 -08:00

572 lines
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/*
* OMAP2 Power Management Routines
*
* Copyright (C) 2005 Texas Instruments, Inc.
* Copyright (C) 2006-2008 Nokia Corporation
*
* Written by:
* Richard Woodruff <r-woodruff2@ti.com>
* Tony Lindgren
* Juha Yrjola
* Amit Kucheria <amit.kucheria@nokia.com>
* Igor Stoppa <igor.stoppa@nokia.com>
*
* Based on pm.c for omap1
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/suspend.h>
#include <linux/sched.h>
#include <linux/proc_fs.h>
#include <linux/interrupt.h>
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/delay.h>
#include <linux/clk.h>
#include <linux/io.h>
#include <linux/irq.h>
#include <linux/time.h>
#include <linux/gpio.h>
#include <linux/console.h>
#include <asm/mach/time.h>
#include <asm/mach/irq.h>
#include <asm/mach-types.h>
#include <mach/irqs.h>
#include <plat/clock.h>
#include <plat/sram.h>
#include <plat/dma.h>
#include <plat/board.h>
#include "prm.h"
#include "prm-regbits-24xx.h"
#include "cm.h"
#include "cm-regbits-24xx.h"
#include "sdrc.h"
#include "pm.h"
#include "control.h"
#include <plat/powerdomain.h>
#include <plat/clockdomain.h>
static void (*omap2_sram_idle)(void);
static void (*omap2_sram_suspend)(u32 dllctrl, void __iomem *sdrc_dlla_ctrl,
void __iomem *sdrc_power);
static struct powerdomain *mpu_pwrdm, *core_pwrdm;
static struct clockdomain *dsp_clkdm, *mpu_clkdm, *wkup_clkdm, *gfx_clkdm;
static struct clk *osc_ck, *emul_ck;
static int omap2_fclks_active(void)
{
u32 f1, f2;
f1 = cm_read_mod_reg(CORE_MOD, CM_FCLKEN1);
f2 = cm_read_mod_reg(CORE_MOD, OMAP24XX_CM_FCLKEN2);
/* Ignore UART clocks. These are handled by UART core (serial.c) */
f1 &= ~(OMAP24XX_EN_UART1_MASK | OMAP24XX_EN_UART2_MASK);
f2 &= ~OMAP24XX_EN_UART3_MASK;
if (f1 | f2)
return 1;
return 0;
}
static void omap2_enter_full_retention(void)
{
u32 l;
struct timespec ts_preidle, ts_postidle, ts_idle;
/* There is 1 reference hold for all children of the oscillator
* clock, the following will remove it. If no one else uses the
* oscillator itself it will be disabled if/when we enter retention
* mode.
*/
clk_disable(osc_ck);
/* Clear old wake-up events */
/* REVISIT: These write to reserved bits? */
prm_write_mod_reg(0xffffffff, CORE_MOD, PM_WKST1);
prm_write_mod_reg(0xffffffff, CORE_MOD, OMAP24XX_PM_WKST2);
prm_write_mod_reg(0xffffffff, WKUP_MOD, PM_WKST);
/*
* Set MPU powerdomain's next power state to RETENTION;
* preserve logic state during retention
*/
pwrdm_set_logic_retst(mpu_pwrdm, PWRDM_POWER_RET);
pwrdm_set_next_pwrst(mpu_pwrdm, PWRDM_POWER_RET);
/* Workaround to kill USB */
l = omap_ctrl_readl(OMAP2_CONTROL_DEVCONF0) | OMAP24XX_USBSTANDBYCTRL;
omap_ctrl_writel(l, OMAP2_CONTROL_DEVCONF0);
omap2_gpio_prepare_for_idle(PWRDM_POWER_RET);
if (omap2_pm_debug) {
omap2_pm_dump(0, 0, 0);
getnstimeofday(&ts_preidle);
}
/* One last check for pending IRQs to avoid extra latency due
* to sleeping unnecessarily. */
if (omap_irq_pending())
goto no_sleep;
/* Block console output in case it is on one of the OMAP UARTs */
if (try_acquire_console_sem())
goto no_sleep;
omap_uart_prepare_idle(0);
omap_uart_prepare_idle(1);
omap_uart_prepare_idle(2);
/* Jump to SRAM suspend code */
omap2_sram_suspend(sdrc_read_reg(SDRC_DLLA_CTRL),
OMAP_SDRC_REGADDR(SDRC_DLLA_CTRL),
OMAP_SDRC_REGADDR(SDRC_POWER));
omap_uart_resume_idle(2);
omap_uart_resume_idle(1);
omap_uart_resume_idle(0);
release_console_sem();
no_sleep:
if (omap2_pm_debug) {
unsigned long long tmp;
getnstimeofday(&ts_postidle);
ts_idle = timespec_sub(ts_postidle, ts_preidle);
tmp = timespec_to_ns(&ts_idle) * NSEC_PER_USEC;
omap2_pm_dump(0, 1, tmp);
}
omap2_gpio_resume_after_idle();
clk_enable(osc_ck);
/* clear CORE wake-up events */
prm_write_mod_reg(0xffffffff, CORE_MOD, PM_WKST1);
prm_write_mod_reg(0xffffffff, CORE_MOD, OMAP24XX_PM_WKST2);
/* wakeup domain events - bit 1: GPT1, bit5 GPIO */
prm_clear_mod_reg_bits(0x4 | 0x1, WKUP_MOD, PM_WKST);
/* MPU domain wake events */
l = prm_read_mod_reg(OCP_MOD, OMAP2_PRCM_IRQSTATUS_MPU_OFFSET);
if (l & 0x01)
prm_write_mod_reg(0x01, OCP_MOD,
OMAP2_PRCM_IRQSTATUS_MPU_OFFSET);
if (l & 0x20)
prm_write_mod_reg(0x20, OCP_MOD,
OMAP2_PRCM_IRQSTATUS_MPU_OFFSET);
/* Mask future PRCM-to-MPU interrupts */
prm_write_mod_reg(0x0, OCP_MOD, OMAP2_PRCM_IRQSTATUS_MPU_OFFSET);
}
static int omap2_i2c_active(void)
{
u32 l;
l = cm_read_mod_reg(CORE_MOD, CM_FCLKEN1);
return l & (OMAP2420_EN_I2C2_MASK | OMAP2420_EN_I2C1_MASK);
}
static int sti_console_enabled;
static int omap2_allow_mpu_retention(void)
{
u32 l;
/* Check for MMC, UART2, UART1, McSPI2, McSPI1 and DSS1. */
l = cm_read_mod_reg(CORE_MOD, CM_FCLKEN1);
if (l & (OMAP2420_EN_MMC_MASK | OMAP24XX_EN_UART2_MASK |
OMAP24XX_EN_UART1_MASK | OMAP24XX_EN_MCSPI2_MASK |
OMAP24XX_EN_MCSPI1_MASK | OMAP24XX_EN_DSS1_MASK))
return 0;
/* Check for UART3. */
l = cm_read_mod_reg(CORE_MOD, OMAP24XX_CM_FCLKEN2);
if (l & OMAP24XX_EN_UART3_MASK)
return 0;
if (sti_console_enabled)
return 0;
return 1;
}
static void omap2_enter_mpu_retention(void)
{
int only_idle = 0;
struct timespec ts_preidle, ts_postidle, ts_idle;
/* Putting MPU into the WFI state while a transfer is active
* seems to cause the I2C block to timeout. Why? Good question. */
if (omap2_i2c_active())
return;
/* The peripherals seem not to be able to wake up the MPU when
* it is in retention mode. */
if (omap2_allow_mpu_retention()) {
/* REVISIT: These write to reserved bits? */
prm_write_mod_reg(0xffffffff, CORE_MOD, PM_WKST1);
prm_write_mod_reg(0xffffffff, CORE_MOD, OMAP24XX_PM_WKST2);
prm_write_mod_reg(0xffffffff, WKUP_MOD, PM_WKST);
/* Try to enter MPU retention */
prm_write_mod_reg((0x01 << OMAP_POWERSTATE_SHIFT) |
OMAP_LOGICRETSTATE_MASK,
MPU_MOD, OMAP2_PM_PWSTCTRL);
} else {
/* Block MPU retention */
prm_write_mod_reg(OMAP_LOGICRETSTATE_MASK, MPU_MOD,
OMAP2_PM_PWSTCTRL);
only_idle = 1;
}
if (omap2_pm_debug) {
omap2_pm_dump(only_idle ? 2 : 1, 0, 0);
getnstimeofday(&ts_preidle);
}
omap2_sram_idle();
if (omap2_pm_debug) {
unsigned long long tmp;
getnstimeofday(&ts_postidle);
ts_idle = timespec_sub(ts_postidle, ts_preidle);
tmp = timespec_to_ns(&ts_idle) * NSEC_PER_USEC;
omap2_pm_dump(only_idle ? 2 : 1, 1, tmp);
}
}
static int omap2_can_sleep(void)
{
if (omap2_fclks_active())
return 0;
if (!omap_uart_can_sleep())
return 0;
if (osc_ck->usecount > 1)
return 0;
if (omap_dma_running())
return 0;
return 1;
}
static void omap2_pm_idle(void)
{
local_irq_disable();
local_fiq_disable();
if (!omap2_can_sleep()) {
if (omap_irq_pending())
goto out;
omap2_enter_mpu_retention();
goto out;
}
if (omap_irq_pending())
goto out;
omap2_enter_full_retention();
out:
local_fiq_enable();
local_irq_enable();
}
static int omap2_pm_prepare(void)
{
/* We cannot sleep in idle until we have resumed */
disable_hlt();
return 0;
}
static int omap2_pm_suspend(void)
{
u32 wken_wkup, mir1;
wken_wkup = prm_read_mod_reg(WKUP_MOD, PM_WKEN);
wken_wkup &= ~OMAP24XX_EN_GPT1_MASK;
prm_write_mod_reg(wken_wkup, WKUP_MOD, PM_WKEN);
/* Mask GPT1 */
mir1 = omap_readl(0x480fe0a4);
omap_writel(1 << 5, 0x480fe0ac);
omap_uart_prepare_suspend();
omap2_enter_full_retention();
omap_writel(mir1, 0x480fe0a4);
prm_write_mod_reg(wken_wkup, WKUP_MOD, PM_WKEN);
return 0;
}
static int omap2_pm_enter(suspend_state_t state)
{
int ret = 0;
switch (state) {
case PM_SUSPEND_STANDBY:
case PM_SUSPEND_MEM:
ret = omap2_pm_suspend();
break;
default:
ret = -EINVAL;
}
return ret;
}
static void omap2_pm_finish(void)
{
enable_hlt();
}
static struct platform_suspend_ops omap_pm_ops = {
.prepare = omap2_pm_prepare,
.enter = omap2_pm_enter,
.finish = omap2_pm_finish,
.valid = suspend_valid_only_mem,
};
/* XXX This function should be shareable between OMAP2xxx and OMAP3 */
static int __init clkdms_setup(struct clockdomain *clkdm, void *unused)
{
clkdm_clear_all_wkdeps(clkdm);
clkdm_clear_all_sleepdeps(clkdm);
if (clkdm->flags & CLKDM_CAN_ENABLE_AUTO)
omap2_clkdm_allow_idle(clkdm);
else if (clkdm->flags & CLKDM_CAN_FORCE_SLEEP &&
atomic_read(&clkdm->usecount) == 0)
omap2_clkdm_sleep(clkdm);
return 0;
}
static void __init prcm_setup_regs(void)
{
int i, num_mem_banks;
struct powerdomain *pwrdm;
/* Enable autoidle */
prm_write_mod_reg(OMAP24XX_AUTOIDLE_MASK, OCP_MOD,
OMAP2_PRCM_SYSCONFIG_OFFSET);
/*
* Set CORE powerdomain memory banks to retain their contents
* during RETENTION
*/
num_mem_banks = pwrdm_get_mem_bank_count(core_pwrdm);
for (i = 0; i < num_mem_banks; i++)
pwrdm_set_mem_retst(core_pwrdm, i, PWRDM_POWER_RET);
/* Set CORE powerdomain's next power state to RETENTION */
pwrdm_set_next_pwrst(core_pwrdm, PWRDM_POWER_RET);
/*
* Set MPU powerdomain's next power state to RETENTION;
* preserve logic state during retention
*/
pwrdm_set_logic_retst(mpu_pwrdm, PWRDM_POWER_RET);
pwrdm_set_next_pwrst(mpu_pwrdm, PWRDM_POWER_RET);
/* Force-power down DSP, GFX powerdomains */
pwrdm = clkdm_get_pwrdm(dsp_clkdm);
pwrdm_set_next_pwrst(pwrdm, PWRDM_POWER_OFF);
omap2_clkdm_sleep(dsp_clkdm);
pwrdm = clkdm_get_pwrdm(gfx_clkdm);
pwrdm_set_next_pwrst(pwrdm, PWRDM_POWER_OFF);
omap2_clkdm_sleep(gfx_clkdm);
/*
* Clear clockdomain wakeup dependencies and enable
* hardware-supervised idle for all clkdms
*/
clkdm_for_each(clkdms_setup, NULL);
clkdm_add_wkdep(mpu_clkdm, wkup_clkdm);
/* Enable clock autoidle for all domains */
cm_write_mod_reg(OMAP24XX_AUTO_CAM_MASK |
OMAP24XX_AUTO_MAILBOXES_MASK |
OMAP24XX_AUTO_WDT4_MASK |
OMAP2420_AUTO_WDT3_MASK |
OMAP24XX_AUTO_MSPRO_MASK |
OMAP2420_AUTO_MMC_MASK |
OMAP24XX_AUTO_FAC_MASK |
OMAP2420_AUTO_EAC_MASK |
OMAP24XX_AUTO_HDQ_MASK |
OMAP24XX_AUTO_UART2_MASK |
OMAP24XX_AUTO_UART1_MASK |
OMAP24XX_AUTO_I2C2_MASK |
OMAP24XX_AUTO_I2C1_MASK |
OMAP24XX_AUTO_MCSPI2_MASK |
OMAP24XX_AUTO_MCSPI1_MASK |
OMAP24XX_AUTO_MCBSP2_MASK |
OMAP24XX_AUTO_MCBSP1_MASK |
OMAP24XX_AUTO_GPT12_MASK |
OMAP24XX_AUTO_GPT11_MASK |
OMAP24XX_AUTO_GPT10_MASK |
OMAP24XX_AUTO_GPT9_MASK |
OMAP24XX_AUTO_GPT8_MASK |
OMAP24XX_AUTO_GPT7_MASK |
OMAP24XX_AUTO_GPT6_MASK |
OMAP24XX_AUTO_GPT5_MASK |
OMAP24XX_AUTO_GPT4_MASK |
OMAP24XX_AUTO_GPT3_MASK |
OMAP24XX_AUTO_GPT2_MASK |
OMAP2420_AUTO_VLYNQ_MASK |
OMAP24XX_AUTO_DSS_MASK,
CORE_MOD, CM_AUTOIDLE1);
cm_write_mod_reg(OMAP24XX_AUTO_UART3_MASK |
OMAP24XX_AUTO_SSI_MASK |
OMAP24XX_AUTO_USB_MASK,
CORE_MOD, CM_AUTOIDLE2);
cm_write_mod_reg(OMAP24XX_AUTO_SDRC_MASK |
OMAP24XX_AUTO_GPMC_MASK |
OMAP24XX_AUTO_SDMA_MASK,
CORE_MOD, CM_AUTOIDLE3);
cm_write_mod_reg(OMAP24XX_AUTO_PKA_MASK |
OMAP24XX_AUTO_AES_MASK |
OMAP24XX_AUTO_RNG_MASK |
OMAP24XX_AUTO_SHA_MASK |
OMAP24XX_AUTO_DES_MASK,
CORE_MOD, OMAP24XX_CM_AUTOIDLE4);
cm_write_mod_reg(OMAP2420_AUTO_DSP_IPI_MASK, OMAP24XX_DSP_MOD,
CM_AUTOIDLE);
/* Put DPLL and both APLLs into autoidle mode */
cm_write_mod_reg((0x03 << OMAP24XX_AUTO_DPLL_SHIFT) |
(0x03 << OMAP24XX_AUTO_96M_SHIFT) |
(0x03 << OMAP24XX_AUTO_54M_SHIFT),
PLL_MOD, CM_AUTOIDLE);
cm_write_mod_reg(OMAP24XX_AUTO_OMAPCTRL_MASK |
OMAP24XX_AUTO_WDT1_MASK |
OMAP24XX_AUTO_MPU_WDT_MASK |
OMAP24XX_AUTO_GPIOS_MASK |
OMAP24XX_AUTO_32KSYNC_MASK |
OMAP24XX_AUTO_GPT1_MASK,
WKUP_MOD, CM_AUTOIDLE);
/* REVISIT: Configure number of 32 kHz clock cycles for sys_clk
* stabilisation */
prm_write_mod_reg(15 << OMAP_SETUP_TIME_SHIFT, OMAP24XX_GR_MOD,
OMAP2_PRCM_CLKSSETUP_OFFSET);
/* Configure automatic voltage transition */
prm_write_mod_reg(2 << OMAP_SETUP_TIME_SHIFT, OMAP24XX_GR_MOD,
OMAP2_PRCM_VOLTSETUP_OFFSET);
prm_write_mod_reg(OMAP24XX_AUTO_EXTVOLT_MASK |
(0x1 << OMAP24XX_SETOFF_LEVEL_SHIFT) |
OMAP24XX_MEMRETCTRL_MASK |
(0x1 << OMAP24XX_SETRET_LEVEL_SHIFT) |
(0x0 << OMAP24XX_VOLT_LEVEL_SHIFT),
OMAP24XX_GR_MOD, OMAP2_PRCM_VOLTCTRL_OFFSET);
/* Enable wake-up events */
prm_write_mod_reg(OMAP24XX_EN_GPIOS_MASK | OMAP24XX_EN_GPT1_MASK,
WKUP_MOD, PM_WKEN);
}
static int __init omap2_pm_init(void)
{
u32 l;
if (!cpu_is_omap24xx())
return -ENODEV;
printk(KERN_INFO "Power Management for OMAP2 initializing\n");
l = prm_read_mod_reg(OCP_MOD, OMAP2_PRCM_REVISION_OFFSET);
printk(KERN_INFO "PRCM revision %d.%d\n", (l >> 4) & 0x0f, l & 0x0f);
/* Look up important powerdomains */
mpu_pwrdm = pwrdm_lookup("mpu_pwrdm");
if (!mpu_pwrdm)
pr_err("PM: mpu_pwrdm not found\n");
core_pwrdm = pwrdm_lookup("core_pwrdm");
if (!core_pwrdm)
pr_err("PM: core_pwrdm not found\n");
/* Look up important clockdomains */
mpu_clkdm = clkdm_lookup("mpu_clkdm");
if (!mpu_clkdm)
pr_err("PM: mpu_clkdm not found\n");
wkup_clkdm = clkdm_lookup("wkup_clkdm");
if (!wkup_clkdm)
pr_err("PM: wkup_clkdm not found\n");
dsp_clkdm = clkdm_lookup("dsp_clkdm");
if (!dsp_clkdm)
pr_err("PM: dsp_clkdm not found\n");
gfx_clkdm = clkdm_lookup("gfx_clkdm");
if (!gfx_clkdm)
pr_err("PM: gfx_clkdm not found\n");
osc_ck = clk_get(NULL, "osc_ck");
if (IS_ERR(osc_ck)) {
printk(KERN_ERR "could not get osc_ck\n");
return -ENODEV;
}
if (cpu_is_omap242x()) {
emul_ck = clk_get(NULL, "emul_ck");
if (IS_ERR(emul_ck)) {
printk(KERN_ERR "could not get emul_ck\n");
clk_put(osc_ck);
return -ENODEV;
}
}
prcm_setup_regs();
/* Hack to prevent MPU retention when STI console is enabled. */
{
const struct omap_sti_console_config *sti;
sti = omap_get_config(OMAP_TAG_STI_CONSOLE,
struct omap_sti_console_config);
if (sti != NULL && sti->enable)
sti_console_enabled = 1;
}
/*
* We copy the assembler sleep/wakeup routines to SRAM.
* These routines need to be in SRAM as that's the only
* memory the MPU can see when it wakes up.
*/
if (cpu_is_omap24xx()) {
omap2_sram_idle = omap_sram_push(omap24xx_idle_loop_suspend,
omap24xx_idle_loop_suspend_sz);
omap2_sram_suspend = omap_sram_push(omap24xx_cpu_suspend,
omap24xx_cpu_suspend_sz);
}
suspend_set_ops(&omap_pm_ops);
pm_idle = omap2_pm_idle;
return 0;
}
late_initcall(omap2_pm_init);
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