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More ACPI updates for 4.20-rc1

Browse source 
Rework the handling of the P-unit semaphore on Intel Baytrail and
 Cherrytrail systems to avoid race conditions and excessive overhead
 related to it (Hans de Goede).
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Merge tag 'acpi-4.20-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm

Pull more ACPI updates from Rafael Wysocki:
 "Rework the handling of the P-unit semaphore on Intel Baytrail and
  Cherrytrail systems to avoid race conditions and excessive overhead
  related to it (Hans de Goede)"

* tag 'acpi-4.20-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  ACPI / PMIC: xpower: Add depends on IOSF_MBI to Kconfig entry
  i2c: designware: Cleanup bus lock handling
  ACPI / PMIC: xpower: Block P-Unit I2C access during read-modify-write
  x86: baytrail/cherrytrail: Rework and move P-Unit PMIC bus semaphore code
This commit is contained in:
Linus Torvalds 2018-10-30 09:15:31 -07:00
commit c2101d0182
8 changed files with 250 additions and 183 deletions
Download patch file Download diff file Expand all files Collapse all files

139
drivers/i2c/busses/i2c-designware-baytrail.c
View file

@ -3,141 +3,15 @@
* Intel BayTrail PMIC I2C bus semaphore implementaion
* Copyright (c) 2014, Intel Corporation.
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/acpi.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/pm_qos.h>
#include <asm/iosf_mbi.h>
#include "i2c-designware-core.h"
#define SEMAPHORE_TIMEOUT 500
#define PUNIT_SEMAPHORE 0x7
#define PUNIT_SEMAPHORE_CHT 0x10e
#define PUNIT_SEMAPHORE_BIT BIT(0)
#define PUNIT_SEMAPHORE_ACQUIRE BIT(1)
static unsigned long acquired;
static u32 get_sem_addr(struct dw_i2c_dev *dev)
{
if (dev->flags & MODEL_CHERRYTRAIL)
return PUNIT_SEMAPHORE_CHT;
else
return PUNIT_SEMAPHORE;
}
static int get_sem(struct dw_i2c_dev *dev, u32 *sem)
{
u32 addr = get_sem_addr(dev);
u32 data;
int ret;
ret = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, addr, &data);
if (ret) {
dev_err(dev->dev, "iosf failed to read punit semaphore\n");
return ret;
}
*sem = data & PUNIT_SEMAPHORE_BIT;
return 0;
}
static void reset_semaphore(struct dw_i2c_dev *dev)
{
if (iosf_mbi_modify(BT_MBI_UNIT_PMC, MBI_REG_READ, get_sem_addr(dev),
0, PUNIT_SEMAPHORE_BIT))
dev_err(dev->dev, "iosf failed to reset punit semaphore during write\n");
pm_qos_update_request(&dev->pm_qos, PM_QOS_DEFAULT_VALUE);
iosf_mbi_call_pmic_bus_access_notifier_chain(MBI_PMIC_BUS_ACCESS_END,
NULL);
iosf_mbi_punit_release();
}
static int baytrail_i2c_acquire(struct dw_i2c_dev *dev)
{
u32 addr;
u32 sem = PUNIT_SEMAPHORE_ACQUIRE;
int ret;
unsigned long start, end;
might_sleep();
if (!dev || !dev->dev)
return -ENODEV;
if (!dev->release_lock)
return 0;
iosf_mbi_punit_acquire();
iosf_mbi_call_pmic_bus_access_notifier_chain(MBI_PMIC_BUS_ACCESS_BEGIN,
NULL);
/*
* Disallow the CPU to enter C6 or C7 state, entering these states
* requires the punit to talk to the pmic and if this happens while
* we're holding the semaphore, the SoC hangs.
*/
pm_qos_update_request(&dev->pm_qos, 0);
addr = get_sem_addr(dev);
/* host driver writes to side band semaphore register */
ret = iosf_mbi_write(BT_MBI_UNIT_PMC, MBI_REG_WRITE, addr, sem);
if (ret) {
dev_err(dev->dev, "iosf punit semaphore request failed\n");
goto out;
}
/* host driver waits for bit 0 to be set in semaphore register */
start = jiffies;
end = start + msecs_to_jiffies(SEMAPHORE_TIMEOUT);
do {
ret = get_sem(dev, &sem);
if (!ret && sem) {
acquired = jiffies;
dev_dbg(dev->dev, "punit semaphore acquired after %ums\n",
jiffies_to_msecs(jiffies - start));
return 0;
}
usleep_range(1000, 2000);
} while (time_before(jiffies, end));
dev_err(dev->dev, "punit semaphore timed out, resetting\n");
out:
reset_semaphore(dev);
ret = iosf_mbi_read(BT_MBI_UNIT_PMC, MBI_REG_READ, addr, &sem);
if (ret)
dev_err(dev->dev, "iosf failed to read punit semaphore\n");
else
dev_err(dev->dev, "PUNIT SEM: %d\n", sem);
WARN_ON(1);
return -ETIMEDOUT;
}
static void baytrail_i2c_release(struct dw_i2c_dev *dev)
{
if (!dev || !dev->dev)
return;
if (!dev->acquire_lock)
return;
reset_semaphore(dev);
dev_dbg(dev->dev, "punit semaphore held for %ums\n",
jiffies_to_msecs(jiffies - acquired));
}
int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev)
{
acpi_status status;
@ -162,18 +36,9 @@ int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev)
return -EPROBE_DEFER;
dev_info(dev->dev, "I2C bus managed by PUNIT\n");
dev->acquire_lock = baytrail_i2c_acquire;
dev->release_lock = baytrail_i2c_release;
dev->acquire_lock = iosf_mbi_block_punit_i2c_access;
dev->release_lock = iosf_mbi_unblock_punit_i2c_access;
dev->shared_with_punit = true;
pm_qos_add_request(&dev->pm_qos, PM_QOS_CPU_DMA_LATENCY,
PM_QOS_DEFAULT_VALUE);
return 0;
}
void i2c_dw_remove_lock_support(struct dw_i2c_dev *dev)
{
if (dev->acquire_lock)
pm_qos_remove_request(&dev->pm_qos);
}

4
drivers/i2c/busses/i2c-designware-common.c
View file

@ -269,7 +269,7 @@ int i2c_dw_acquire_lock(struct dw_i2c_dev *dev)
if (!dev->acquire_lock)
return 0;
ret = dev->acquire_lock(dev);
ret = dev->acquire_lock();
if (!ret)
return 0;
@ -281,7 +281,7 @@ int i2c_dw_acquire_lock(struct dw_i2c_dev *dev)
void i2c_dw_release_lock(struct dw_i2c_dev *dev)
{
if (dev->release_lock)
dev->release_lock(dev);
dev->release_lock();
}
/*

9
drivers/i2c/busses/i2c-designware-core.h
View file

@ -10,7 +10,6 @@
*/
#include <linux/i2c.h>
#include <linux/pm_qos.h>
#define DW_IC_DEFAULT_FUNCTIONALITY (I2C_FUNC_I2C | \
I2C_FUNC_SMBUS_BYTE | \
@ -209,7 +208,6 @@
* @fp_lcnt: fast plus LCNT value
* @hs_hcnt: high speed HCNT value
* @hs_lcnt: high speed LCNT value
* @pm_qos: pm_qos_request used while holding a hardware lock on the bus
* @acquire_lock: function to acquire a hardware lock on the bus
* @release_lock: function to release a hardware lock on the bus
* @shared_with_punit: true if this bus is shared with the SoCs PUNIT
@ -263,9 +261,8 @@ struct dw_i2c_dev {
u16 fp_lcnt;
u16 hs_hcnt;
u16 hs_lcnt;
struct pm_qos_request pm_qos;
int (*acquire_lock)(struct dw_i2c_dev *dev);
void (*release_lock)(struct dw_i2c_dev *dev);
int (*acquire_lock)(void);
void (*release_lock)(void);
bool shared_with_punit;
void (*disable)(struct dw_i2c_dev *dev);
void (*disable_int)(struct dw_i2c_dev *dev);
@ -322,8 +319,6 @@ static inline int i2c_dw_probe_slave(struct dw_i2c_dev *dev) { return -EINVAL; }
#if IS_ENABLED(CONFIG_I2C_DESIGNWARE_BAYTRAIL)
extern int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev);
extern void i2c_dw_remove_lock_support(struct dw_i2c_dev *dev);
#else
static inline int i2c_dw_probe_lock_support(struct dw_i2c_dev *dev) { return 0; }
static inline void i2c_dw_remove_lock_support(struct dw_i2c_dev *dev) {}
#endif

2
drivers/i2c/busses/i2c-designware-platdrv.c
View file

@ -418,8 +418,6 @@ static int dw_i2c_plat_remove(struct platform_device *pdev)
if (!IS_ERR_OR_NULL(dev->rst))
reset_control_assert(dev->rst);
i2c_dw_remove_lock_support(dev);
return 0;
}