1 files changed, 316 insertions, 2 deletions

diff --git a/drivers/soc/samsung/exynos-pmu.c b/drivers/soc/samsung/exynos-pmu.c
index 250537d7cfd6..a77288f49d24 100644
--- a/drivers/soc/samsung/exynos-pmu.c
+++ b/drivers/soc/samsung/exynos-pmu.c
@@ -5,6 +5,9 @@
 //
 // Exynos - CPU PMU(Power Management Unit) support
 
+#include <linux/array_size.h>
+#include <linux/arm-smccc.h>
+#include <linux/cpuhotplug.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/mfd/core.h>
@@ -12,19 +15,151 @@
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
 #include <linux/delay.h>
+#include <linux/regmap.h>
 
 #include <linux/soc/samsung/exynos-regs-pmu.h>
 #include <linux/soc/samsung/exynos-pmu.h>
 
 #include "exynos-pmu.h"
 
+#define PMUALIVE_MASK			GENMASK(13, 0)
+#define TENSOR_SET_BITS			(BIT(15) | BIT(14))
+#define TENSOR_CLR_BITS			BIT(15)
+#define TENSOR_SMC_PMU_SEC_REG		0x82000504
+#define TENSOR_PMUREG_READ		0
+#define TENSOR_PMUREG_WRITE		1
+#define TENSOR_PMUREG_RMW		2
+
 struct exynos_pmu_context {
 	struct device *dev;
 	const struct exynos_pmu_data *pmu_data;
+	struct regmap *pmureg;
+	struct regmap *pmuintrgen;
 };
 
 void __iomem *pmu_base_addr;
 static struct exynos_pmu_context *pmu_context;
+/* forward declaration */
+static struct platform_driver exynos_pmu_driver;
+
+/*
+ * Tensor SoCs are configured so that PMU_ALIVE registers can only be written
+ * from EL3, but are still read accessible. As Linux needs to write some of
+ * these registers, the following functions are provided and exposed via
+ * regmap.
+ *
+ * Note: This SMC interface is known to be implemented on gs101 and derivative
+ * SoCs.
+ */
+
+/* Write to a protected PMU register. */
+static int tensor_sec_reg_write(void *context, unsigned int reg,
+				unsigned int val)
+{
+	struct arm_smccc_res res;
+	unsigned long pmu_base = (unsigned long)context;
+
+	arm_smccc_smc(TENSOR_SMC_PMU_SEC_REG, pmu_base + reg,
+		      TENSOR_PMUREG_WRITE, val, 0, 0, 0, 0, &res);
+
+	/* returns -EINVAL if access isn't allowed or 0 */
+	if (res.a0)
+		pr_warn("%s(): SMC failed: %d\n", __func__, (int)res.a0);
+
+	return (int)res.a0;
+}
+
+/* Read/Modify/Write a protected PMU register. */
+static int tensor_sec_reg_rmw(void *context, unsigned int reg,
+			      unsigned int mask, unsigned int val)
+{
+	struct arm_smccc_res res;
+	unsigned long pmu_base = (unsigned long)context;
+
+	arm_smccc_smc(TENSOR_SMC_PMU_SEC_REG, pmu_base + reg,
+		      TENSOR_PMUREG_RMW, mask, val, 0, 0, 0, &res);
+
+	/* returns -EINVAL if access isn't allowed or 0 */
+	if (res.a0)
+		pr_warn("%s(): SMC failed: %d\n", __func__, (int)res.a0);
+
+	return (int)res.a0;
+}
+
+/*
+ * Read a protected PMU register. All PMU registers can be read by Linux.
+ * Note: The SMC read register is not used, as only registers that can be
+ * written are readable via SMC.
+ */
+static int tensor_sec_reg_read(void *context, unsigned int reg,
+			       unsigned int *val)
+{
+	*val = pmu_raw_readl(reg);
+	return 0;
+}
+
+/*
+ * For SoCs that have set/clear bit hardware this function can be used when
+ * the PMU register will be accessed by multiple masters.
+ *
+ * For example, to set bits 13:8 in PMU reg offset 0x3e80
+ * tensor_set_bits_atomic(ctx, 0x3e80, 0x3f00, 0x3f00);
+ *
+ * Set bit 8, and clear bits 13:9 PMU reg offset 0x3e80
+ * tensor_set_bits_atomic(0x3e80, 0x100, 0x3f00);
+ */
+static int tensor_set_bits_atomic(void *ctx, unsigned int offset, u32 val,
+				  u32 mask)
+{
+	int ret;
+	unsigned int i;
+
+	for (i = 0; i < 32; i++) {
+		if (!(mask & BIT(i)))
+			continue;
+
+		offset &= ~TENSOR_SET_BITS;
+
+		if (val & BIT(i))
+			offset |= TENSOR_SET_BITS;
+		else
+			offset |= TENSOR_CLR_BITS;
+
+		ret = tensor_sec_reg_write(ctx, offset, i);
+		if (ret)
+			return ret;
+	}
+	return 0;
+}
+
+static bool tensor_is_atomic(unsigned int reg)
+{
+	/*
+	 * Use atomic operations for PMU_ALIVE registers (offset 0~0x3FFF)
+	 * as the target registers can be accessed by multiple masters. SFRs
+	 * that don't support atomic are added to the switch statement below.
+	 */
+	if (reg > PMUALIVE_MASK)
+		return false;
+
+	switch (reg) {
+	case GS101_SYSIP_DAT0:
+	case GS101_SYSTEM_CONFIGURATION:
+		return false;
+	default:
+		return true;
+	}
+}
+
+static int tensor_sec_update_bits(void *ctx, unsigned int reg,
+				  unsigned int mask, unsigned int val)
+{
+
+	if (!tensor_is_atomic(reg))
+		return tensor_sec_reg_rmw(ctx, reg, mask, val);
+
+	return tensor_set_bits_atomic(ctx, reg, val, mask);
+}
 
 void pmu_raw_writel(u32 val, u32 offset)
 {
@@ -75,11 +210,32 @@ void exynos_sys_powerdown_conf(enum sys_powerdown mode)
 #define exynos_pmu_data_arm_ptr(data)	NULL
 #endif
 
+static const struct regmap_config regmap_smccfg = {
+	.name = "pmu_regs",
+	.reg_bits = 32,
+	.reg_stride = 4,
+	.val_bits = 32,
+	.fast_io = true,
+	.use_single_read = true,
+	.use_single_write = true,
+	.reg_read = tensor_sec_reg_read,
+	.reg_write = tensor_sec_reg_write,
+	.reg_update_bits = tensor_sec_update_bits,
+};
+
+static const struct exynos_pmu_data gs101_pmu_data = {
+	.pmu_secure = true,
+	.pmu_cpuhp = true,
+};
+
 /*
  * PMU platform driver and devicetree bindings.
  */
 static const struct of_device_id exynos_pmu_of_device_ids[] = {
 	{
+		.compatible = "google,gs101-pmu",
+		.data = &gs101_pmu_data,
+	}, {
 		.compatible = "samsung,exynos3250-pmu",
 		.data = exynos_pmu_data_arm_ptr(exynos3250_pmu_data),
 	}, {
@@ -113,19 +269,125 @@ static const struct mfd_cell exynos_pmu_devs[] = {
 	{ .name = "exynos-clkout", },
 };
 
+/**
+ * exynos_get_pmu_regmap() - Obtain pmureg regmap
+ *
+ * Find the pmureg regmap previously configured in probe() and return regmap
+ * pointer.
+ *
+ * Return: A pointer to regmap if found or ERR_PTR error value.
+ */
 struct regmap *exynos_get_pmu_regmap(void)
 {
 	struct device_node *np = of_find_matching_node(NULL,
 						      exynos_pmu_of_device_ids);
 	if (np)
-		return syscon_node_to_regmap(np);
+		return exynos_get_pmu_regmap_by_phandle(np, NULL);
 	return ERR_PTR(-ENODEV);
 }
 EXPORT_SYMBOL_GPL(exynos_get_pmu_regmap);
 
+/**
+ * exynos_get_pmu_regmap_by_phandle() - Obtain pmureg regmap via phandle
+ * @np: Device node holding PMU phandle property
+ * @propname: Name of property holding phandle value
+ *
+ * Find the pmureg regmap previously configured in probe() and return regmap
+ * pointer.
+ *
+ * Return: A pointer to regmap if found or ERR_PTR error value.
+ */
+struct regmap *exynos_get_pmu_regmap_by_phandle(struct device_node *np,
+						const char *propname)
+{
+	struct device_node *pmu_np;
+	struct device *dev;
+
+	if (propname)
+		pmu_np = of_parse_phandle(np, propname, 0);
+	else
+		pmu_np = np;
+
+	if (!pmu_np)
+		return ERR_PTR(-ENODEV);
+
+	/*
+	 * Determine if exynos-pmu device has probed and therefore regmap
+	 * has been created and can be returned to the caller. Otherwise we
+	 * return -EPROBE_DEFER.
+	 */
+	dev = driver_find_device_by_of_node(&exynos_pmu_driver.driver,
+					    (void *)pmu_np);
+
+	if (propname)
+		of_node_put(pmu_np);
+
+	if (!dev)
+		return ERR_PTR(-EPROBE_DEFER);
+
+	return syscon_node_to_regmap(pmu_np);
+}
+EXPORT_SYMBOL_GPL(exynos_get_pmu_regmap_by_phandle);
+
+/*
+ * CPU_INFORM register hint values which are used by
+ * EL3 firmware (el3mon).
+ */
+#define CPU_INFORM_CLEAR	0
+#define CPU_INFORM_C2		1
+
+static int gs101_cpuhp_pmu_online(unsigned int cpu)
+{
+	unsigned int cpuhint = smp_processor_id();
+	u32 reg, mask;
+
+	/* clear cpu inform hint */
+	regmap_write(pmu_context->pmureg, GS101_CPU_INFORM(cpuhint),
+		     CPU_INFORM_CLEAR);
+
+	mask = BIT(cpu);
+
+	regmap_update_bits(pmu_context->pmuintrgen, GS101_GRP2_INTR_BID_ENABLE,
+			   mask, (0 << cpu));
+
+	regmap_read(pmu_context->pmuintrgen, GS101_GRP2_INTR_BID_UPEND, &reg);
+
+	regmap_write(pmu_context->pmuintrgen, GS101_GRP2_INTR_BID_CLEAR,
+		     reg & mask);
+
+	return 0;
+}
+
+static int gs101_cpuhp_pmu_offline(unsigned int cpu)
+{
+	u32 reg, mask;
+	unsigned int cpuhint = smp_processor_id();
+
+	/* set cpu inform hint */
+	regmap_write(pmu_context->pmureg, GS101_CPU_INFORM(cpuhint),
+		     CPU_INFORM_C2);
+
+	mask = BIT(cpu);
+	regmap_update_bits(pmu_context->pmuintrgen, GS101_GRP2_INTR_BID_ENABLE,
+			   mask, BIT(cpu));
+
+	regmap_read(pmu_context->pmuintrgen, GS101_GRP1_INTR_BID_UPEND, &reg);
+	regmap_write(pmu_context->pmuintrgen, GS101_GRP1_INTR_BID_CLEAR,
+		     reg & mask);
+
+	mask = (BIT(cpu + 8));
+	regmap_read(pmu_context->pmuintrgen, GS101_GRP1_INTR_BID_UPEND, &reg);
+	regmap_write(pmu_context->pmuintrgen, GS101_GRP1_INTR_BID_CLEAR,
+		     reg & mask);
+	return 0;
+}
+
 static int exynos_pmu_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
+	struct regmap_config pmu_regmcfg;
+	struct regmap *regmap;
+	struct resource *res;
 	int ret;
 
 	pmu_base_addr = devm_platform_ioremap_resource(pdev, 0);
@@ -137,9 +399,61 @@ static int exynos_pmu_probe(struct platform_device *pdev)
 			GFP_KERNEL);
 	if (!pmu_context)
 		return -ENOMEM;
-	pmu_context->dev = dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -ENODEV;
+
 	pmu_context->pmu_data = of_device_get_match_data(dev);
 
+	/* For SoCs that secure PMU register writes use custom regmap */
+	if (pmu_context->pmu_data && pmu_context->pmu_data->pmu_secure) {
+		pmu_regmcfg = regmap_smccfg;
+		pmu_regmcfg.max_register = resource_size(res) -
+					   pmu_regmcfg.reg_stride;
+		/* Need physical address for SMC call */
+		regmap = devm_regmap_init(dev, NULL,
+					  (void *)(uintptr_t)res->start,
+					  &pmu_regmcfg);
+
+		if (IS_ERR(regmap))
+			return dev_err_probe(&pdev->dev, PTR_ERR(regmap),
+					     "regmap init failed\n");
+
+		ret = of_syscon_register_regmap(dev->of_node, regmap);
+		if (ret)
+			return ret;
+	} else {
+		/* let syscon create mmio regmap */
+		regmap = syscon_node_to_regmap(dev->of_node);
+		if (IS_ERR(regmap))
+			return dev_err_probe(&pdev->dev, PTR_ERR(regmap),
+					     "syscon_node_to_regmap failed\n");
+	}
+
+	pmu_context->pmureg = regmap;
+	pmu_context->dev = dev;
+
+	if (pmu_context->pmu_data && pmu_context->pmu_data->pmu_cpuhp) {
+		pmu_context->pmuintrgen = syscon_regmap_lookup_by_phandle(dev->of_node,
+							"google,pmu-intr-gen-syscon");
+		if (IS_ERR(pmu_context->pmuintrgen)) {
+			/*
+			 * To maintain support for older DTs that didn't specify syscon phandle
+			 * just issue a warning rather than fail to probe.
+			 */
+			dev_warn(&pdev->dev, "pmu-intr-gen syscon unavailable\n");
+		} else {
+			cpuhp_setup_state(CPUHP_BP_PREPARE_DYN,
+					  "soc/exynos-pmu:prepare",
+					  gs101_cpuhp_pmu_online, NULL);
+
+			cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
+					  "soc/exynos-pmu:online",
+					  NULL, gs101_cpuhp_pmu_offline);
+		}
+	}
+
 	if (pmu_context->pmu_data && pmu_context->pmu_data->pmu_init)
 		pmu_context->pmu_data->pmu_init();