Re: [RFC v3 3/7] platform/x86: intel_pmc_ipc: Use regmap calls for GCR updates
From: sathyanarayanan kuppuswamy
Date: Tue Oct 03 2017 - 21:16:52 EST
Hi Andy,
On 10/01/2017 07:48 AM, Andy Shevchenko wrote:
On Tue, Sep 5, 2017 at 8:37 AM,
<sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> wrote:
From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
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 refactoring the
current GCR read/write/update functions with regmap APIs.
Since it sounds as candidate for stable,
Yes.
can we have split it to just
as less as possible intrusive fix + moving to regmap as a separate
change?
If we have to split it into two patches then,
Patch #1 will fix the "sleep in atomic context issue" by replacing
mutex_lock() with spin_lock()
in GCR read/write APIs to protect the GCR memory updates.
Patch #2 will remove GCR read/write/update APIs and replace it with
regmap APIs. But along with this
change we will also remove the spin_lock() added in previous patch
because regmap calls are already
protected by its own locking mechanism.
Since Patch #2 will clean up what we do in Patch #1, Do we need to split
it into two patches?
It should include Fixes: tag as well I suppose.
Agree. I will add Fixes tag in next version.
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
---
drivers/platform/x86/Kconfig | 1 +
drivers/platform/x86/intel_pmc_ipc.c | 115 ++++++++++++-----------------------
2 files changed, 40 insertions(+), 76 deletions(-)
diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 80b8795..45f4e79 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1054,6 +1054,7 @@ config PVPANIC
config INTEL_PMC_IPC
tristate "Intel PMC IPC Driver"
depends on ACPI
+ select REGMAP_MMIO
---help---
This driver provides support for PMC control on some Intel platforms.
The PMC is an ARC processor which defines IPC commands for communication
diff --git a/drivers/platform/x86/intel_pmc_ipc.c b/drivers/platform/x86/intel_pmc_ipc.c
index 021dcf6..40a25f8 100644
--- a/drivers/platform/x86/intel_pmc_ipc.c
+++ b/drivers/platform/x86/intel_pmc_ipc.c
@@ -31,9 +31,11 @@
#include <linux/atomic.h>
#include <linux/notifier.h>
#include <linux/suspend.h>
+#include <linux/spinlock.h>
#include <linux/acpi.h>
#include <linux/io-64-nonatomic-lo-hi.h>
#include <linux/mfd/core.h>
+#include <linux/regmap.h>
#include <asm/intel_pmc_ipc.h>
@@ -125,7 +127,7 @@ static struct intel_pmc_ipc_dev {
/* gcr */
void __iomem *gcr_mem_base;
- bool has_gcr_regs;
+ struct regmap *gcr_regs;
/* Telemetry */
u8 telem_res_inval;
@@ -150,6 +152,14 @@ static char *ipc_err_sources[] = {
"Unsigned kernel",
};
+static struct regmap_config gcr_regmap_config = {
+ .reg_bits = 32,
+ .reg_stride = 4,
+ .val_bits = 32,
+ .fast_io = true,
+ .max_register = PLAT_RESOURCE_GCR_SIZE,
+};
+
/* Prevent concurrent calls to the PMC */
static DEFINE_MUTEX(ipclock);
@@ -183,21 +193,6 @@ static inline u32 ipc_data_readl(u32 offset)
return readl(ipcdev.ipc_base + IPC_READ_BUFFER + offset);
}
-static inline u64 gcr_data_readq(u32 offset)
-{
- return readq(ipcdev.gcr_mem_base + offset);
-}
-
-static inline int is_gcr_valid(u32 offset)
-{
- if (!ipcdev.has_gcr_regs)
- return -EACCES;
-
- if (offset > PLAT_RESOURCE_GCR_SIZE)
- return -EINVAL;
-
- return 0;
-}
/**
* intel_pmc_gcr_read() - Read PMC GCR register
@@ -210,21 +205,10 @@ static inline int is_gcr_valid(u32 offset)
*/
int intel_pmc_gcr_read(u32 offset, u32 *data)
{
- int ret;
-
- mutex_lock(&ipclock);
-
- ret = is_gcr_valid(offset);
- if (ret < 0) {
- mutex_unlock(&ipclock);
- return ret;
- }
-
- *data = readl(ipcdev.gcr_mem_base + offset);
-
- mutex_unlock(&ipclock);
+ if (!ipcdev.gcr_regs)
+ return -EACCES;
- return 0;
+ return regmap_read(ipcdev.gcr_regs, offset, data);
}
EXPORT_SYMBOL_GPL(intel_pmc_gcr_read);
@@ -240,21 +224,10 @@ EXPORT_SYMBOL_GPL(intel_pmc_gcr_read);
*/
int intel_pmc_gcr_write(u32 offset, u32 data)
{
- int ret;
-
- mutex_lock(&ipclock);
-
- ret = is_gcr_valid(offset);
- if (ret < 0) {
- mutex_unlock(&ipclock);
- return ret;
- }
-
- writel(data, ipcdev.gcr_mem_base + offset);
-
- mutex_unlock(&ipclock);
+ if (!ipcdev.gcr_regs)
+ return -EACCES;
- return 0;
+ return regmap_write(ipcdev.gcr_regs, offset, data);
}
EXPORT_SYMBOL_GPL(intel_pmc_gcr_write);
@@ -271,33 +244,10 @@ EXPORT_SYMBOL_GPL(intel_pmc_gcr_write);
*/
int intel_pmc_gcr_update(u32 offset, u32 mask, u32 val)
{
- u32 new_val;
- int ret = 0;
-
- mutex_lock(&ipclock);
-
- ret = is_gcr_valid(offset);
- if (ret < 0)
- goto gcr_ipc_unlock;
-
- new_val = readl(ipcdev.gcr_mem_base + offset);
-
- new_val &= ~mask;
- new_val |= val & mask;
-
- writel(new_val, ipcdev.gcr_mem_base + offset);
-
- new_val = readl(ipcdev.gcr_mem_base + offset);
-
- /* check whether the bit update is successful */
- if ((new_val & mask) != (val & mask)) {
- ret = -EIO;
- goto gcr_ipc_unlock;
- }
+ if (!ipcdev.gcr_regs)
+ return -EACCES;
-gcr_ipc_unlock:
- mutex_unlock(&ipclock);
- return ret;
+ return regmap_update_bits(ipcdev.gcr_regs, offset, mask, val);
}
EXPORT_SYMBOL_GPL(intel_pmc_gcr_update);
@@ -776,16 +726,24 @@ static int ipc_plat_get_res(struct platform_device *pdev)
int intel_pmc_s0ix_counter_read(u64 *data)
{
u64 deep, shlw;
+ int ret;
- if (!ipcdev.has_gcr_regs)
+ if (!ipcdev.gcr_regs)
return -EACCES;
- deep = gcr_data_readq(PMC_GCR_TELEM_DEEP_S0IX_REG);
- shlw = gcr_data_readq(PMC_GCR_TELEM_SHLW_S0IX_REG);
+ ret = regmap_bulk_read(ipcdev.gcr_regs, PMC_GCR_TELEM_DEEP_S0IX_REG,
+ &deep, 2);
+ if (ret)
+ return ret;
+
+ ret = regmap_bulk_read(ipcdev.gcr_regs, PMC_GCR_TELEM_SHLW_S0IX_REG,
+ &shlw, 2);
+ if (ret)
+ return ret;
*data = S0IX_RESIDENCY_IN_USECS(deep, shlw);
- return 0;
+ return ret;
}
EXPORT_SYMBOL_GPL(intel_pmc_s0ix_counter_read);
@@ -817,6 +775,13 @@ static int ipc_plat_probe(struct platform_device *pdev)
return ret;
}
+ ipcdev.gcr_regs = devm_regmap_init_mmio_clk(ipcdev.dev, NULL,
+ ipcdev.gcr_mem_base, &gcr_regmap_config);
+ if (IS_ERR(ipcdev.gcr_regs)) {
+ dev_err(ipcdev.dev, "gcr_regs regmap init failed\n");
+ return PTR_ERR(ipcdev.gcr_regs);;
+ }
+
ret = ipc_create_pmc_devices(pdev);
if (ret) {
dev_err(&pdev->dev, "Failed to create pmc devices\n");
@@ -836,8 +801,6 @@ static int ipc_plat_probe(struct platform_device *pdev)
return ret;
}
- ipcdev.has_gcr_regs = true;
-
return 0;
}
--
2.7.4
--
Sathyanarayanan Kuppuswamy
Linux kernel developer