platform/x86:intel/pmc: Revert "Enable the ACPI PM Timer to be turned off when suspended"

Commit e86c818 ("platform/x86:intel/pmc: Enable the ACPI PM Timer to
be turned off when suspended") can cause the suspend process to hang as
the pmcdev->lock in the pmc_core_acpi_pm_timer_suspend_resume might already
be held by the pmc_core_mphy_pg_show or pmc_core_pll_show if the userspace
gets frozen when these functions are being executed.

Also, pmc_core_acpi_pm_timer_suspend_resume must not sleep, as this
function is called indirectly by the tick_freeze function in
kernel/time/tick-common.c, which holds the spinlock.

Revert the changes for now to fix these issues.

Fixes: e86c818 ("platform/x86:intel/pmc: Enable the ACPI PM Timer to be turned off when suspended")
Reported-by: Luca Coelho <[email protected]>
Closes: https://lore.kernel.org/lkml/[email protected]/
Signed-off-by: Marek Maslanka <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Hans de Goede <[email protected]>
Signed-off-by: Hans de Goede <[email protected]>

Author: MaslankaMarek

drivers/platform/x86/intel/pmc/adl.c

@@ -295,8 +295,6 @@ const struct pmc_reg_map adl_reg_map = {
 	.ppfear_buckets = CNP_PPFEAR_NUM_ENTRIES,
 	.pm_cfg_offset = CNP_PMC_PM_CFG_OFFSET,
 	.pm_read_disable_bit = CNP_PMC_READ_DISABLE_BIT,
-	.acpi_pm_tmr_ctl_offset = SPT_PMC_ACPI_PM_TMR_CTL_OFFSET,
-	.acpi_pm_tmr_disable_bit = SPT_PMC_BIT_ACPI_PM_TMR_DISABLE,
 	.ltr_ignore_max = ADL_NUM_IP_IGN_ALLOWED,
 	.lpm_num_modes = ADL_LPM_NUM_MODES,
 	.lpm_num_maps = ADL_LPM_NUM_MAPS,

drivers/platform/x86/intel/pmc/cnp.c

@@ -200,8 +200,6 @@ const struct pmc_reg_map cnp_reg_map = {
 	.ppfear_buckets = CNP_PPFEAR_NUM_ENTRIES,
 	.pm_cfg_offset = CNP_PMC_PM_CFG_OFFSET,
 	.pm_read_disable_bit = CNP_PMC_READ_DISABLE_BIT,
-	.acpi_pm_tmr_ctl_offset = SPT_PMC_ACPI_PM_TMR_CTL_OFFSET,
-	.acpi_pm_tmr_disable_bit = SPT_PMC_BIT_ACPI_PM_TMR_DISABLE,
 	.ltr_ignore_max = CNP_NUM_IP_IGN_ALLOWED,
 	.etr3_offset = ETR3_OFFSET,
 };

drivers/platform/x86/intel/pmc/core.c

@@ -11,7 +11,6 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include <linux/acpi_pmtmr.h>
 #include <linux/bitfield.h>
 #include <linux/debugfs.h>
 #include <linux/delay.h>
@@ -1258,39 +1257,6 @@ static bool pmc_core_is_pson_residency_enabled(struct pmc_dev *pmcdev)
 	return val == 1;
 }
 
-/*
- * Enable or disable ACPI PM Timer
- *
- * This function is intended to be a callback for ACPI PM suspend/resume event.
- * The ACPI PM Timer is enabled on resume only if it was enabled during suspend.
- */
-static void pmc_core_acpi_pm_timer_suspend_resume(void *data, bool suspend)
-{
-	struct pmc_dev *pmcdev = data;
-	struct pmc *pmc = pmcdev->pmcs[PMC_IDX_MAIN];
-	const struct pmc_reg_map *map = pmc->map;
-	bool enabled;
-	u32 reg;
-
-	if (!map->acpi_pm_tmr_ctl_offset)
-		return;
-
-	guard(mutex)(&pmcdev->lock);
-
-	if (!suspend && !pmcdev->enable_acpi_pm_timer_on_resume)
-		return;
-
-	reg = pmc_core_reg_read(pmc, map->acpi_pm_tmr_ctl_offset);
-	enabled = !(reg & map->acpi_pm_tmr_disable_bit);
-	if (suspend)
-		reg |= map->acpi_pm_tmr_disable_bit;
-	else
-		reg &= ~map->acpi_pm_tmr_disable_bit;
-	pmc_core_reg_write(pmc, map->acpi_pm_tmr_ctl_offset, reg);
-
-	pmcdev->enable_acpi_pm_timer_on_resume = suspend && enabled;
-}
-
 static void pmc_core_dbgfs_unregister(struct pmc_dev *pmcdev)
 {
 	debugfs_remove_recursive(pmcdev->dbgfs_dir);
@@ -1486,7 +1452,6 @@ static int pmc_core_probe(struct platform_device *pdev)
 	struct pmc_dev *pmcdev;
 	const struct x86_cpu_id *cpu_id;
 	int (*core_init)(struct pmc_dev *pmcdev);
-	const struct pmc_reg_map *map;
 	struct pmc *primary_pmc;
 	int ret;
 
@@ -1545,11 +1510,6 @@ static int pmc_core_probe(struct platform_device *pdev)
 	pm_report_max_hw_sleep(FIELD_MAX(SLP_S0_RES_COUNTER_MASK) *
 			       pmc_core_adjust_slp_s0_step(primary_pmc, 1));
 
-	map = primary_pmc->map;
-	if (map->acpi_pm_tmr_ctl_offset)
-		acpi_pmtmr_register_suspend_resume_callback(pmc_core_acpi_pm_timer_suspend_resume,
-							 pmcdev);
-
 	device_initialized = true;
 	dev_info(&pdev->dev, " initialized\n");
 
@@ -1559,12 +1519,6 @@ static int pmc_core_probe(struct platform_device *pdev)
 static void pmc_core_remove(struct platform_device *pdev)
 {
 	struct pmc_dev *pmcdev = platform_get_drvdata(pdev);
-	const struct pmc *pmc = pmcdev->pmcs[PMC_IDX_MAIN];
-	const struct pmc_reg_map *map = pmc->map;
-
-	if (map->acpi_pm_tmr_ctl_offset)
-		acpi_pmtmr_unregister_suspend_resume_callback();
-
 	pmc_core_dbgfs_unregister(pmcdev);
 	pmc_core_clean_structure(pdev);
 }

drivers/platform/x86/intel/pmc/core.h

@@ -68,8 +68,6 @@ struct telem_endpoint;
 #define SPT_PMC_LTR_SCC				0x3A0
 #define SPT_PMC_LTR_ISH				0x3A4
 
-#define SPT_PMC_ACPI_PM_TMR_CTL_OFFSET		0x18FC
-
 /* Sunrise Point: PGD PFET Enable Ack Status Registers */
 enum ppfear_regs {
 	SPT_PMC_XRAM_PPFEAR0A = 0x590,
@@ -150,8 +148,6 @@ enum ppfear_regs {
 #define SPT_PMC_VRIC1_SLPS0LVEN			BIT(13)
 #define SPT_PMC_VRIC1_XTALSDQDIS		BIT(22)
 
-#define SPT_PMC_BIT_ACPI_PM_TMR_DISABLE		BIT(1)
-
 /* Cannonlake Power Management Controller register offsets */
 #define CNP_PMC_SLPS0_DBG_OFFSET		0x10B4
 #define CNP_PMC_PM_CFG_OFFSET			0x1818
@@ -355,8 +351,6 @@ struct pmc_reg_map {
 	const u8  *lpm_reg_index;
 	const u32 pson_residency_offset;
 	const u32 pson_residency_counter_step;
-	const u32 acpi_pm_tmr_ctl_offset;
-	const u32 acpi_pm_tmr_disable_bit;
 };
 
 /**
@@ -432,8 +426,6 @@ struct pmc_dev {
 	u32 die_c6_offset;
 	struct telem_endpoint *punit_ep;
 	struct pmc_info *regmap_list;
-
-	bool enable_acpi_pm_timer_on_resume;
 };
 
 enum pmc_index {

drivers/platform/x86/intel/pmc/icl.c

@@ -46,8 +46,6 @@ const struct pmc_reg_map icl_reg_map = {
 	.ppfear_buckets = ICL_PPFEAR_NUM_ENTRIES,
 	.pm_cfg_offset = CNP_PMC_PM_CFG_OFFSET,
 	.pm_read_disable_bit = CNP_PMC_READ_DISABLE_BIT,
-	.acpi_pm_tmr_ctl_offset = SPT_PMC_ACPI_PM_TMR_CTL_OFFSET,
-	.acpi_pm_tmr_disable_bit = SPT_PMC_BIT_ACPI_PM_TMR_DISABLE,
 	.ltr_ignore_max = ICL_NUM_IP_IGN_ALLOWED,
 	.etr3_offset = ETR3_OFFSET,
 };

drivers/platform/x86/intel/pmc/mtl.c

@@ -462,8 +462,6 @@ const struct pmc_reg_map mtl_socm_reg_map = {
 	.ppfear_buckets = MTL_SOCM_PPFEAR_NUM_ENTRIES,
 	.pm_cfg_offset = CNP_PMC_PM_CFG_OFFSET,
 	.pm_read_disable_bit = CNP_PMC_READ_DISABLE_BIT,
-	.acpi_pm_tmr_ctl_offset = SPT_PMC_ACPI_PM_TMR_CTL_OFFSET,
-	.acpi_pm_tmr_disable_bit = SPT_PMC_BIT_ACPI_PM_TMR_DISABLE,
 	.lpm_num_maps = ADL_LPM_NUM_MAPS,
 	.ltr_ignore_max = MTL_SOCM_NUM_IP_IGN_ALLOWED,
 	.lpm_res_counter_step_x2 = TGL_PMC_LPM_RES_COUNTER_STEP_X2,

drivers/platform/x86/intel/pmc/tgl.c

@@ -197,8 +197,6 @@ const struct pmc_reg_map tgl_reg_map = {
 	.ppfear_buckets = ICL_PPFEAR_NUM_ENTRIES,
 	.pm_cfg_offset = CNP_PMC_PM_CFG_OFFSET,
 	.pm_read_disable_bit = CNP_PMC_READ_DISABLE_BIT,
-	.acpi_pm_tmr_ctl_offset = SPT_PMC_ACPI_PM_TMR_CTL_OFFSET,
-	.acpi_pm_tmr_disable_bit = SPT_PMC_BIT_ACPI_PM_TMR_DISABLE,
 	.ltr_ignore_max = TGL_NUM_IP_IGN_ALLOWED,
 	.lpm_num_maps = TGL_LPM_NUM_MAPS,
 	.lpm_res_counter_step_x2 = TGL_PMC_LPM_RES_COUNTER_STEP_X2,