[RFC v6 1/9] platform/x86: intel_pmc_ipc: Use spin_lock to protect GCR updates
From: sathyanarayanan.kuppuswamy@linux.intel.com
Date: 2017-10-19 00:23:48
Also in:
linux-watchdog, lkml, platform-driver-x86
Subsystem:
the rest, x86 platform drivers · Maintainers:
Linus Torvalds, Hans de Goede, Ilpo Järvinen
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Currently, update_no_reboot_bit() function implemented in this driver
uses mutex_lock() to protect its register updates. But this function is
called with in atomic context in iTCO_wdt_start() and iTCO_wdt_stop()
functions in iTCO_wdt.c driver, which in turn causes "sleeping into
atomic context" issue. This patch fixes this issue by replacing the
mutex_lock() with spin_lock() to protect the GCR read/write/update APIs.
Fixes: 9d855d468dc6 ("platform/x86: intel_pmc_ipc: Fix iTCO_wdt GCS memory mapping failure")
Signed-off-by: Kuppuswamy Sathyanarayanan <redacted>
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
---
drivers/platform/x86/intel_pmc_ipc.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
diff --git a/drivers/platform/x86/intel_pmc_ipc.c b/drivers/platform/x86/intel_pmc_ipc.c
index bb792a5..af88221 100644
--- a/drivers/platform/x86/intel_pmc_ipc.c
+++ b/drivers/platform/x86/intel_pmc_ipc.c@@ -33,6 +33,7 @@ #include <linux/suspend.h> #include <linux/acpi.h> #include <linux/io-64-nonatomic-lo-hi.h> +#include <linux/spinlock.h> #include <asm/intel_pmc_ipc.h>
@@ -131,6 +132,7 @@ static struct intel_pmc_ipc_dev { /* gcr */ void __iomem *gcr_mem_base; bool has_gcr_regs; + spinlock_t gcr_lock; /* punit */ struct platform_device *punit_dev;
@@ -225,17 +227,17 @@ int intel_pmc_gcr_read(u32 offset, u32 *data) { int ret; - mutex_lock(&ipclock); + spin_lock(&ipcdev.gcr_lock); ret = is_gcr_valid(offset); if (ret < 0) { - mutex_unlock(&ipclock); + spin_unlock(&ipcdev.gcr_lock); return ret; } *data = readl(ipcdev.gcr_mem_base + offset); - mutex_unlock(&ipclock); + spin_unlock(&ipcdev.gcr_lock); return 0; }
@@ -255,17 +257,17 @@ int intel_pmc_gcr_write(u32 offset, u32 data) { int ret; - mutex_lock(&ipclock); + spin_lock(&ipcdev.gcr_lock); ret = is_gcr_valid(offset); if (ret < 0) { - mutex_unlock(&ipclock); + spin_unlock(&ipcdev.gcr_lock); return ret; } writel(data, ipcdev.gcr_mem_base + offset); - mutex_unlock(&ipclock); + spin_unlock(&ipcdev.gcr_lock); return 0; }
@@ -287,7 +289,7 @@ int intel_pmc_gcr_update(u32 offset, u32 mask, u32 val) u32 new_val; int ret = 0; - mutex_lock(&ipclock); + spin_lock(&ipcdev.gcr_lock); ret = is_gcr_valid(offset); if (ret < 0)
@@ -309,7 +311,7 @@ int intel_pmc_gcr_update(u32 offset, u32 mask, u32 val) } gcr_ipc_unlock: - mutex_unlock(&ipclock); + spin_unlock(&ipcdev.gcr_lock); return ret; } EXPORT_SYMBOL_GPL(intel_pmc_gcr_update);
@@ -487,6 +489,8 @@ static int ipc_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) ipcdev.dev = &pci_dev_get(pdev)->dev; ipcdev.irq_mode = IPC_TRIGGER_MODE_IRQ; + spin_lock_init(&ipcdev.gcr_lock); + ret = pci_enable_device(pdev); if (ret) return ret;
@@ -924,6 +928,8 @@ static int ipc_plat_probe(struct platform_device *pdev) ipcdev.irq_mode = IPC_TRIGGER_MODE_IRQ; init_completion(&ipcdev.cmd_complete); + spin_lock_init(&ipcdev.gcr_lock); + ipcdev.irq = platform_get_irq(pdev, 0); if (ipcdev.irq < 0) { dev_err(&pdev->dev, "Failed to get irq\n");
--
2.7.4