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mei: gsc: use polling instead of interrupts

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A work-around for a HW issue in XEHPSDV that manifests itself when SW reads
a gsc register when gsc is sending an interrupt. The work-around is
to disable interrupts and to use polling instead.

Cc: James Ausmus <james.ausmus@intel.com>
Signed-off-by: Vitaly Lubart <vitaly.lubart@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Signed-off-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220907215113.1596567-7-tomas.winkler@intel.com
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
This commit is contained in:
Tomas Winkler 2022-09-08 00:51:03 +03:00 committed by Joonas Lahtinen
parent 2d427248aa
commit 5b063995de
3 changed files with 128 additions and 15 deletions
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48
drivers/misc/mei/gsc-me.c
View file

@ -13,6 +13,7 @@
#include <linux/ktime.h>
#include <linux/delay.h>
#include <linux/pm_runtime.h>
#include <linux/kthread.h>
#include "mei_dev.h"
#include "hw-me.h"
@ -66,13 +67,28 @@ static int mei_gsc_probe(struct auxiliary_device *aux_dev,
dev_set_drvdata(device, dev);
ret = devm_request_threaded_irq(device, hw->irq,
mei_me_irq_quick_handler,
mei_me_irq_thread_handler,
IRQF_ONESHOT, KBUILD_MODNAME, dev);
if (ret) {
dev_err(device, "irq register failed %d\n", ret);
goto err;
/* use polling */
if (mei_me_hw_use_polling(hw)) {
mei_disable_interrupts(dev);
mei_clear_interrupts(dev);
init_waitqueue_head(&hw->wait_active);
hw->is_active = true; /* start in active mode for initialization */
hw->polling_thread = kthread_run(mei_me_polling_thread, dev,
"kmegscirqd/%s", dev_name(device));
if (IS_ERR(hw->polling_thread)) {
ret = PTR_ERR(hw->polling_thread);
dev_err(device, "unable to create kernel thread: %d\n", ret);
goto err;
}
} else {
ret = devm_request_threaded_irq(device, hw->irq,
mei_me_irq_quick_handler,
mei_me_irq_thread_handler,
IRQF_ONESHOT, KBUILD_MODNAME, dev);
if (ret) {
dev_err(device, "irq register failed %d\n", ret);
goto err;
}
}
pm_runtime_get_noresume(device);
@ -98,7 +114,8 @@ static int mei_gsc_probe(struct auxiliary_device *aux_dev,
register_err:
mei_stop(dev);
devm_free_irq(device, hw->irq, dev);
if (!mei_me_hw_use_polling(hw))
devm_free_irq(device, hw->irq, dev);
err:
dev_err(device, "probe failed: %d\n", ret);
@ -119,12 +136,17 @@ static void mei_gsc_remove(struct auxiliary_device *aux_dev)
mei_stop(dev);
hw = to_me_hw(dev);
if (mei_me_hw_use_polling(hw))
kthread_stop(hw->polling_thread);
mei_deregister(dev);
pm_runtime_disable(&aux_dev->dev);
mei_disable_interrupts(dev);
devm_free_irq(&aux_dev->dev, hw->irq, dev);
if (!mei_me_hw_use_polling(hw))
devm_free_irq(&aux_dev->dev, hw->irq, dev);
}
static int __maybe_unused mei_gsc_pm_suspend(struct device *device)
@ -185,6 +207,9 @@ static int __maybe_unused mei_gsc_pm_runtime_suspend(struct device *device)
if (mei_write_is_idle(dev)) {
hw = to_me_hw(dev);
hw->pg_state = MEI_PG_ON;
if (mei_me_hw_use_polling(hw))
hw->is_active = false;
ret = 0;
} else {
ret = -EAGAIN;
@ -209,6 +234,11 @@ static int __maybe_unused mei_gsc_pm_runtime_resume(struct device *device)
hw = to_me_hw(dev);
hw->pg_state = MEI_PG_OFF;
if (mei_me_hw_use_polling(hw)) {
hw->is_active = true;
wake_up(&hw->wait_active);
}
mutex_unlock(&dev->device_lock);
irq_ret = mei_me_irq_thread_handler(1, dev);

80
drivers/misc/mei/hw-me.c
View file

@ -1,6 +1,6 @@
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2003-2020, Intel Corporation. All rights reserved.
* Copyright (c) 2003-2022, Intel Corporation. All rights reserved.
* Intel Management Engine Interface (Intel MEI) Linux driver
*/
@ -10,6 +10,7 @@
#include <linux/interrupt.h>
#include <linux/pm_runtime.h>
#include <linux/sizes.h>
#include <linux/delay.h>
#include "mei_dev.h"
#include "hbm.h"
@ -327,9 +328,12 @@ static void mei_me_intr_clear(struct mei_device *dev)
*/
static void mei_me_intr_enable(struct mei_device *dev)
{
u32 hcsr = mei_hcsr_read(dev);
u32 hcsr;
hcsr |= H_CSR_IE_MASK;
if (mei_me_hw_use_polling(to_me_hw(dev)))
return;
hcsr = mei_hcsr_read(dev) | H_CSR_IE_MASK;
mei_hcsr_set(dev, hcsr);
}
@ -354,6 +358,9 @@ static void mei_me_synchronize_irq(struct mei_device *dev)
{
struct mei_me_hw *hw = to_me_hw(dev);
if (mei_me_hw_use_polling(hw))
return;
synchronize_irq(hw->irq);
}
@ -380,7 +387,10 @@ static void mei_me_host_set_ready(struct mei_device *dev)
{
u32 hcsr = mei_hcsr_read(dev);
hcsr |= H_CSR_IE_MASK | H_IG | H_RDY;
if (!mei_me_hw_use_polling(to_me_hw(dev)))
hcsr |= H_CSR_IE_MASK;
hcsr |= H_IG | H_RDY;
mei_hcsr_set(dev, hcsr);
}
@ -1174,7 +1184,7 @@ static int mei_me_hw_reset(struct mei_device *dev, bool intr_enable)
hcsr |= H_RST | H_IG | H_CSR_IS_MASK;
if (!intr_enable)
if (!intr_enable || mei_me_hw_use_polling(to_me_hw(dev)))
hcsr &= ~H_CSR_IE_MASK;
dev->recvd_hw_ready = false;
@ -1329,6 +1339,66 @@ irqreturn_t mei_me_irq_thread_handler(int irq, void *dev_id)
}
EXPORT_SYMBOL_GPL(mei_me_irq_thread_handler);
#define MEI_POLLING_TIMEOUT_ACTIVE 100
#define MEI_POLLING_TIMEOUT_IDLE 500
/**
* mei_me_polling_thread - interrupt register polling thread
*
* The thread monitors the interrupt source register and calls
* mei_me_irq_thread_handler() to handle the firmware
* input.
*
* The function polls in MEI_POLLING_TIMEOUT_ACTIVE timeout
* in case there was an event, in idle case the polling
* time increases yet again by MEI_POLLING_TIMEOUT_ACTIVE
* up to MEI_POLLING_TIMEOUT_IDLE.
*
* @_dev: mei device
*
* Return: always 0
*/
int mei_me_polling_thread(void *_dev)
{
struct mei_device *dev = _dev;
irqreturn_t irq_ret;
long polling_timeout = MEI_POLLING_TIMEOUT_ACTIVE;
dev_dbg(dev->dev, "kernel thread is running\n");
while (!kthread_should_stop()) {
struct mei_me_hw *hw = to_me_hw(dev);
u32 hcsr;
wait_event_timeout(hw->wait_active,
hw->is_active || kthread_should_stop(),
msecs_to_jiffies(MEI_POLLING_TIMEOUT_IDLE));
if (kthread_should_stop())
break;
hcsr = mei_hcsr_read(dev);
if (me_intr_src(hcsr)) {
polling_timeout = MEI_POLLING_TIMEOUT_ACTIVE;
irq_ret = mei_me_irq_thread_handler(1, dev);
if (irq_ret != IRQ_HANDLED)
dev_err(dev->dev, "irq_ret %d\n", irq_ret);
} else {
/*
* Increase timeout by MEI_POLLING_TIMEOUT_ACTIVE
* up to MEI_POLLING_TIMEOUT_IDLE
*/
polling_timeout = clamp_val(polling_timeout + MEI_POLLING_TIMEOUT_ACTIVE,
MEI_POLLING_TIMEOUT_ACTIVE,
MEI_POLLING_TIMEOUT_IDLE);
}
schedule_timeout_interruptible(msecs_to_jiffies(polling_timeout));
}
return 0;
}
EXPORT_SYMBOL_GPL(mei_me_polling_thread);
static const struct mei_hw_ops mei_me_hw_ops = {
.trc_status = mei_me_trc_status,

15
drivers/misc/mei/hw-me.h
View file

@ -1,6 +1,6 @@
/* SPDX-License-Identifier: GPL-2.0 */
/*
* Copyright (c) 2012-2020, Intel Corporation. All rights reserved.
* Copyright (c) 2012-2022, Intel Corporation. All rights reserved.
* Intel Management Engine Interface (Intel MEI) Linux driver
*/
@ -51,6 +51,9 @@ struct mei_cfg {
* @d0i3_supported: di03 support
* @hbuf_depth: depth of hardware host/write buffer in slots
* @read_fws: read FW status register handler
* @polling_thread: interrupt polling thread
* @wait_active: the polling thread activity wait queue
* @is_active: the device is active
*/
struct mei_me_hw {
const struct mei_cfg *cfg;
@ -60,10 +63,19 @@ struct mei_me_hw {
bool d0i3_supported;
u8 hbuf_depth;
int (*read_fws)(const struct mei_device *dev, int where, u32 *val);
/* polling */
struct task_struct *polling_thread;
wait_queue_head_t wait_active;
bool is_active;
};
#define to_me_hw(dev) (struct mei_me_hw *)((dev)->hw)
static inline bool mei_me_hw_use_polling(const struct mei_me_hw *hw)
{
return hw->irq < 0;
}
/**
* enum mei_cfg_idx - indices to platform specific configurations.
*
@ -127,5 +139,6 @@ int mei_me_pg_exit_sync(struct mei_device *dev);
irqreturn_t mei_me_irq_quick_handler(int irq, void *dev_id);
irqreturn_t mei_me_irq_thread_handler(int irq, void *dev_id);
int mei_me_polling_thread(void *_dev);
#endif /* _MEI_INTERFACE_H_ */