[PATCH v1 2/2] platform/x86: intel_pmc_ipc: Use regmap calls for GCR updates

[sathyanarayanan . kuppuswamy]

From: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>

This patch adds support for regmap based implementation for GCR
read/write/update APIs.

Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
---
 drivers/platform/x86/Kconfig         |   1 +
 drivers/platform/x86/intel_pmc_ipc.c | 124 +++++++++++++----------------------
 2 files changed, 46 insertions(+), 79 deletions(-)

This patch was originally part of "SCU/PMC/PUNIT IPC driver clean up" series. But I have
split them into two sets because we need more thorough review on generic IPC driver
design patches (second set).

https://www.spinics.net/lists/linux-watchdog/msg12796.html

Changes since previous set version (v8):
 * Removed gcr_mem_base variable.

diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig
index 2c745e8..ac618fd 100644
--- a/drivers/platform/x86/Kconfig
+++ b/drivers/platform/x86/Kconfig
@@ -1087,6 +1087,7 @@ 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 fadf721..650144a 100644
--- a/drivers/platform/x86/intel_pmc_ipc.c
+++ b/drivers/platform/x86/intel_pmc_ipc.c
@@ -35,6 +35,7 @@
 #include <linux/acpi.h>
 #include <linux/io-64-nonatomic-lo-hi.h>
 #include <linux/spinlock.h>
+#include <linux/regmap.h>
 
 #include <asm/intel_pmc_ipc.h>
 
@@ -125,9 +126,7 @@ static struct intel_pmc_ipc_dev {
 	struct completion cmd_complete;
 
 	/* gcr */
-	void __iomem *gcr_mem_base;
-	bool has_gcr_regs;
-	spinlock_t gcr_lock;
+	struct regmap *gcr_regs;
 } ipcdev;
 
 static char *ipc_err_sources[] = {
@@ -149,6 +148,15 @@ static char *ipc_err_sources[] = {
 		"Unsigned kernel",
 };
 
+static struct regmap_config gcr_regmap_config = {
+	.name = "intel_pmc_gcr",
+	.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);
 
@@ -182,21 +190,6 @@ 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
@@ -209,21 +202,12 @@ static inline int is_gcr_valid(u32 offset)
  */
 int intel_pmc_gcr_read(u32 offset, u32 *data)
 {
-	int ret;
-
-	spin_lock(&ipcdev.gcr_lock);
-
-	ret = is_gcr_valid(offset);
-	if (ret < 0) {
-		spin_unlock(&ipcdev.gcr_lock);
-		return ret;
-	}
-
-	*data = readl(ipcdev.gcr_mem_base + offset);
+	struct intel_pmc_ipc_dev *pmc = &ipcdev;
 
-	spin_unlock(&ipcdev.gcr_lock);
+	if (!pmc->gcr_regs)
+		return -EACCES;
 
-	return 0;
+	return regmap_read(pmc->gcr_regs, offset, data);
 }
 EXPORT_SYMBOL_GPL(intel_pmc_gcr_read);
 
@@ -239,21 +223,12 @@ EXPORT_SYMBOL_GPL(intel_pmc_gcr_read);
  */
 int intel_pmc_gcr_write(u32 offset, u32 data)
 {
-	int ret;
-
-	spin_lock(&ipcdev.gcr_lock);
-
-	ret = is_gcr_valid(offset);
-	if (ret < 0) {
-		spin_unlock(&ipcdev.gcr_lock);
-		return ret;
-	}
-
-	writel(data, ipcdev.gcr_mem_base + offset);
+	struct intel_pmc_ipc_dev *pmc = &ipcdev;
 
-	spin_unlock(&ipcdev.gcr_lock);
+	if (!pmc->gcr_regs)
+		return -EACCES;
 
-	return 0;
+	return regmap_write(pmc->gcr_regs, offset, data);
 }
 EXPORT_SYMBOL_GPL(intel_pmc_gcr_write);
 
@@ -270,33 +245,12 @@ EXPORT_SYMBOL_GPL(intel_pmc_gcr_write);
  */
 int intel_pmc_gcr_update(u32 offset, u32 mask, u32 val)
 {
-	u32 new_val;
-	int ret = 0;
-
-	spin_lock(&ipcdev.gcr_lock);
-
-	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);
+	struct intel_pmc_ipc_dev *pmc = &ipcdev;
 
-	/* check whether the bit update is successful */
-	if ((new_val & mask) != (val & mask)) {
-		ret = -EIO;
-		goto gcr_ipc_unlock;
-	}
+	if (!pmc->gcr_regs)
+		return -EACCES;
 
-gcr_ipc_unlock:
-	spin_unlock(&ipcdev.gcr_lock);
-	return ret;
+	return regmap_update_bits(pmc->gcr_regs, offset, mask, val);
 }
 EXPORT_SYMBOL_GPL(intel_pmc_gcr_update);
 
@@ -475,8 +429,6 @@ static int ipc_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 
 	pmc->irq_mode = IPC_TRIGGER_MODE_IRQ;
 
-	spin_lock_init(&ipcdev.gcr_lock);
-
 	ret = pcim_enable_device(pdev);
 	if (ret)
 		return ret;
@@ -759,7 +711,6 @@ static int ipc_plat_get_res(struct platform_device *pdev)
 		return PTR_ERR(addr);
 
 	ipcdev.ipc_base = addr;
-	ipcdev.gcr_mem_base = addr + PLAT_RESOURCE_GCR_OFFSET;
 
 	return 0;
 }
@@ -772,17 +723,26 @@ static int ipc_plat_get_res(struct platform_device *pdev)
  */
 int intel_pmc_s0ix_counter_read(u64 *data)
 {
+	struct intel_pmc_ipc_dev *pmc = &ipcdev;
 	u64 deep, shlw;
+	int ret;
 
-	if (!ipcdev.has_gcr_regs)
+	if (!pmc->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(pmc->gcr_regs, PMC_GCR_TELEM_DEEP_S0IX_REG,
+			       &deep, 2);
+	if (ret)
+		return ret;
+
+	ret = regmap_bulk_read(pmc->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);
 
@@ -801,7 +761,6 @@ static int ipc_plat_probe(struct platform_device *pdev)
 	ipcdev.dev = &pdev->dev;
 	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) {
@@ -815,6 +774,15 @@ static int ipc_plat_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	/* GCR base address is at ipc_base + PLAT_RESOURCE_GCR_OFFSET */
+	ipcdev.gcr_regs = devm_regmap_init_mmio_clk(ipcdev.dev, NULL,
+				ipcdev.ipc_base + PLAT_RESOURCE_GCR_OFFSET,
+				&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 +804,6 @@ static int ipc_plat_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	ipcdev.has_gcr_regs = true;
-
 	return 0;
 }
 
-- 
2.7.4