| Message ID | 20240219204238.356942-2-peter.griffin@linaro.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Add regmap support to exynos-pmu for protected PMU regs | expand |
On Mon, Feb 19, 2024 at 2:42 PM Peter Griffin <peter.griffin@linaro.org> wrote: > > Some Exynos based SoCs like Tensor gs101 protect the PMU registers for > security hardening reasons so that they are only write accessible in el3 > via an SMC call. > > As most Exynos drivers that need to write PMU registers currently obtain a > regmap via syscon (phys, pinctrl, watchdog). Support for the above usecase > is implemented in this driver using a custom regmap similar to syscon to > handle the SMC call. Platforms that don't secure PMU registers, get a mmio > regmap like before. As regmaps abstract out the underlying register access > changes to the leaf drivers are minimal. > > A new API exynos_get_pmu_regmap_by_phandle() is provided for leaf drivers > that currently use syscon_regmap_lookup_by_phandle(). This also handles > deferred probing. > > Tested-by: Sam Protsenko <semen.protsenko@linaro.org> > Tested-by: Alexey Klimov <alexey.klimov@linaro.org> > Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org> > Signed-off-by: Peter Griffin <peter.griffin@linaro.org> > --- > Changes since v4: > - Use same argument names as in struct regmap_config > - Remove inline keyword and rely on compiler > - Update kerneldoc wording > - property -> propname argument rename > - reverse Xmas tree > - Only call of_node_put() when of_parse_phandle is called > - Collect tags > > Changes since v3: > - Fix PMUALIVE_MASK > - Add TENSOR_ prefix > - clear SET_BITS bits on each loop iteration > - change set_bit to set_bits in func name > - Fix some alignment > - Add missing return on dev_err_probe > - Reduce indentation in loop > > Changes since v2 > - Add select REGMAP to Kconfig > - Add constant for SET/CLEAR bits > - Replace kerneldoc with one line comment > - Fix kerneldoc for EXPORT_SYMBOL_GPL funcs > - remove superfluous extern keyword > - dev_err_probe() on probe error > - shorten regmcfg name > - no compatibles inside probe, use match data > - don't mix declarations with/without initializations > - tensor_sec_reg_read() use mmio to avoid access restrictions > - Collect up Reviewed-by > - const for regmap_config structs > --- > drivers/soc/samsung/Kconfig | 1 + > drivers/soc/samsung/exynos-pmu.c | 235 ++++++++++++++++++++++++- > drivers/soc/samsung/exynos-pmu.h | 1 + > include/linux/soc/samsung/exynos-pmu.h | 11 +- > 4 files changed, 245 insertions(+), 3 deletions(-) > > diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig > index 27ec99af77e3..1a5dfdc978dc 100644 > --- a/drivers/soc/samsung/Kconfig > +++ b/drivers/soc/samsung/Kconfig > @@ -42,6 +42,7 @@ config EXYNOS_PMU > depends on ARCH_EXYNOS || ((ARM || ARM64) && COMPILE_TEST) > select EXYNOS_PMU_ARM_DRIVERS if ARM && ARCH_EXYNOS > select MFD_CORE > + select REGMAP_MMIO > > # There is no need to enable these drivers for ARMv8 > config EXYNOS_PMU_ARM_DRIVERS > diff --git a/drivers/soc/samsung/exynos-pmu.c b/drivers/soc/samsung/exynos-pmu.c > index 250537d7cfd6..d6ae8025fdb4 100644 > --- a/drivers/soc/samsung/exynos-pmu.c > +++ b/drivers/soc/samsung/exynos-pmu.c > @@ -5,6 +5,7 @@ > // > // Exynos - CPU PMU(Power Management Unit) support > > +#include <linux/arm-smccc.h> > #include <linux/of.h> > #include <linux/of_address.h> > #include <linux/mfd/core.h> > @@ -12,19 +13,134 @@ > #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; > }; > > 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 ret; > +} > + > +static int tensor_sec_update_bits(void *ctx, unsigned int reg, > + unsigned int mask, unsigned int val) > +{ > + /* > + * Use atomic operations for PMU_ALIVE registers (offset 0~0x3FFF) > + * as the target registers can be accessed by multiple masters. > + */ > + if (reg > PMUALIVE_MASK) > + 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 +191,41 @@ 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 regmap_config regmap_mmiocfg = { > + .name = "pmu_regs", > + .reg_bits = 32, > + .reg_stride = 4, > + .val_bits = 32, > + .fast_io = true, > + .use_single_read = true, > + .use_single_write = true, > +}; > + > +static const struct exynos_pmu_data gs101_pmu_data = { > + .pmu_secure = 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 +259,75 @@ 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 > + * @property: Name of property holding phandle value This doesn't match the actual param name. > + * > + * 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 exynos_pmu_context *ctx; > + 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); > + > + ctx = dev_get_drvdata(dev); > + > + return ctx->pmureg; > +} > +EXPORT_SYMBOL_GPL(exynos_get_pmu_regmap_by_phandle); > + > 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 +339,38 @@ 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); > + } else { > + /* All other SoCs use a MMIO regmap */ > + pmu_regmcfg = regmap_mmiocfg; > + pmu_regmcfg.max_register = resource_size(res) - > + pmu_regmcfg.reg_stride; > + regmap = devm_regmap_init_mmio(dev, pmu_base_addr, > + &pmu_regmcfg); > + } > + > + if (IS_ERR(regmap)) > + return dev_err_probe(&pdev->dev, PTR_ERR(regmap), > + "regmap init failed\n"); > + > + pmu_context->pmureg = regmap; > + pmu_context->dev = dev; > + > if (pmu_context->pmu_data && pmu_context->pmu_data->pmu_init) > pmu_context->pmu_data->pmu_init(); > > diff --git a/drivers/soc/samsung/exynos-pmu.h b/drivers/soc/samsung/exynos-pmu.h > index 1c652ffd79b4..0a49a2c9a08e 100644 > --- a/drivers/soc/samsung/exynos-pmu.h > +++ b/drivers/soc/samsung/exynos-pmu.h > @@ -21,6 +21,7 @@ struct exynos_pmu_conf { > struct exynos_pmu_data { > const struct exynos_pmu_conf *pmu_config; > const struct exynos_pmu_conf *pmu_config_extra; > + bool pmu_secure; > > void (*pmu_init)(void); > void (*powerdown_conf)(enum sys_powerdown); > diff --git a/include/linux/soc/samsung/exynos-pmu.h b/include/linux/soc/samsung/exynos-pmu.h > index a4f5516cc956..2bd9d12d9a52 100644 > --- a/include/linux/soc/samsung/exynos-pmu.h > +++ b/include/linux/soc/samsung/exynos-pmu.h > @@ -10,6 +10,7 @@ > #define __LINUX_SOC_EXYNOS_PMU_H > > struct regmap; > +struct device_node; > > enum sys_powerdown { > SYS_AFTR, > @@ -20,12 +21,20 @@ enum sys_powerdown { > > extern void exynos_sys_powerdown_conf(enum sys_powerdown mode); > #ifdef CONFIG_EXYNOS_PMU > -extern struct regmap *exynos_get_pmu_regmap(void); > +struct regmap *exynos_get_pmu_regmap(void); > +struct regmap *exynos_get_pmu_regmap_by_phandle(struct device_node *np, > + const char *propname); > #else > static inline struct regmap *exynos_get_pmu_regmap(void) > { > return ERR_PTR(-ENODEV); > } > + > +static inline struct regmap *exynos_get_pmu_regmap_by_phandle(struct device_node *np, > + const char *propname) > +{ > + return ERR_PTR(-ENODEV); > +} > #endif > > #endif /* __LINUX_SOC_EXYNOS_PMU_H */ > -- > 2.44.0.rc0.258.g7320e95886-goog >
Hi Sam, On Mon, 19 Feb 2024 at 23:06, Sam Protsenko <semen.protsenko@linaro.org> wrote: > > On Mon, Feb 19, 2024 at 2:42 PM Peter Griffin <peter.griffin@linaro.org> wrote: > > > > Some Exynos based SoCs like Tensor gs101 protect the PMU registers for > > security hardening reasons so that they are only write accessible in el3 > > via an SMC call. > > > > As most Exynos drivers that need to write PMU registers currently obtain a > > regmap via syscon (phys, pinctrl, watchdog). Support for the above usecase > > is implemented in this driver using a custom regmap similar to syscon to > > handle the SMC call. Platforms that don't secure PMU registers, get a mmio > > regmap like before. As regmaps abstract out the underlying register access > > changes to the leaf drivers are minimal. > > > > A new API exynos_get_pmu_regmap_by_phandle() is provided for leaf drivers > > that currently use syscon_regmap_lookup_by_phandle(). This also handles > > deferred probing. > > > > Tested-by: Sam Protsenko <semen.protsenko@linaro.org> > > Tested-by: Alexey Klimov <alexey.klimov@linaro.org> > > Reviewed-by: Sam Protsenko <semen.protsenko@linaro.org> > > Signed-off-by: Peter Griffin <peter.griffin@linaro.org> > > --- > > Changes since v4: > > - Use same argument names as in struct regmap_config > > - Remove inline keyword and rely on compiler > > - Update kerneldoc wording > > - property -> propname argument rename > > - reverse Xmas tree > > - Only call of_node_put() when of_parse_phandle is called > > - Collect tags > > > > Changes since v3: > > - Fix PMUALIVE_MASK > > - Add TENSOR_ prefix > > - clear SET_BITS bits on each loop iteration > > - change set_bit to set_bits in func name > > - Fix some alignment > > - Add missing return on dev_err_probe > > - Reduce indentation in loop > > > > Changes since v2 > > - Add select REGMAP to Kconfig > > - Add constant for SET/CLEAR bits > > - Replace kerneldoc with one line comment > > - Fix kerneldoc for EXPORT_SYMBOL_GPL funcs > > - remove superfluous extern keyword > > - dev_err_probe() on probe error > > - shorten regmcfg name > > - no compatibles inside probe, use match data > > - don't mix declarations with/without initializations > > - tensor_sec_reg_read() use mmio to avoid access restrictions > > - Collect up Reviewed-by > > - const for regmap_config structs > > --- > > drivers/soc/samsung/Kconfig | 1 + > > drivers/soc/samsung/exynos-pmu.c | 235 ++++++++++++++++++++++++- > > drivers/soc/samsung/exynos-pmu.h | 1 + > > include/linux/soc/samsung/exynos-pmu.h | 11 +- > > 4 files changed, 245 insertions(+), 3 deletions(-) > > > > diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig > > index 27ec99af77e3..1a5dfdc978dc 100644 > > --- a/drivers/soc/samsung/Kconfig > > +++ b/drivers/soc/samsung/Kconfig > > @@ -42,6 +42,7 @@ config EXYNOS_PMU > > depends on ARCH_EXYNOS || ((ARM || ARM64) && COMPILE_TEST) > > select EXYNOS_PMU_ARM_DRIVERS if ARM && ARCH_EXYNOS > > select MFD_CORE > > + select REGMAP_MMIO > > > > # There is no need to enable these drivers for ARMv8 > > config EXYNOS_PMU_ARM_DRIVERS > > diff --git a/drivers/soc/samsung/exynos-pmu.c b/drivers/soc/samsung/exynos-pmu.c > > index 250537d7cfd6..d6ae8025fdb4 100644 > > --- a/drivers/soc/samsung/exynos-pmu.c > > +++ b/drivers/soc/samsung/exynos-pmu.c > > @@ -5,6 +5,7 @@ > > // > > // Exynos - CPU PMU(Power Management Unit) support > > > > +#include <linux/arm-smccc.h> > > #include <linux/of.h> > > #include <linux/of_address.h> > > #include <linux/mfd/core.h> > > @@ -12,19 +13,134 @@ > > #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; > > }; > > > > 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 ret; > > +} > > + > > +static int tensor_sec_update_bits(void *ctx, unsigned int reg, > > + unsigned int mask, unsigned int val) > > +{ > > + /* > > + * Use atomic operations for PMU_ALIVE registers (offset 0~0x3FFF) > > + * as the target registers can be accessed by multiple masters. > > + */ > > + if (reg > PMUALIVE_MASK) > > + 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 +191,41 @@ 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 regmap_config regmap_mmiocfg = { > > + .name = "pmu_regs", > > + .reg_bits = 32, > > + .reg_stride = 4, > > + .val_bits = 32, > > + .fast_io = true, > > + .use_single_read = true, > > + .use_single_write = true, > > +}; > > + > > +static const struct exynos_pmu_data gs101_pmu_data = { > > + .pmu_secure = 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 +259,75 @@ 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 > > + * @property: Name of property holding phandle value > > This doesn't match the actual param name. Doh, I missed the kerneldoc comment in the renaming from property -> propname. I will send a v6 in a moment with this fixed Peter.
diff --git a/drivers/soc/samsung/Kconfig b/drivers/soc/samsung/Kconfig index 27ec99af77e3..1a5dfdc978dc 100644 --- a/drivers/soc/samsung/Kconfig +++ b/drivers/soc/samsung/Kconfig @@ -42,6 +42,7 @@ config EXYNOS_PMU depends on ARCH_EXYNOS || ((ARM || ARM64) && COMPILE_TEST) select EXYNOS_PMU_ARM_DRIVERS if ARM && ARCH_EXYNOS select MFD_CORE + select REGMAP_MMIO # There is no need to enable these drivers for ARMv8 config EXYNOS_PMU_ARM_DRIVERS diff --git a/drivers/soc/samsung/exynos-pmu.c b/drivers/soc/samsung/exynos-pmu.c index 250537d7cfd6..d6ae8025fdb4 100644 --- a/drivers/soc/samsung/exynos-pmu.c +++ b/drivers/soc/samsung/exynos-pmu.c @@ -5,6 +5,7 @@ // // Exynos - CPU PMU(Power Management Unit) support +#include <linux/arm-smccc.h> #include <linux/of.h> #include <linux/of_address.h> #include <linux/mfd/core.h> @@ -12,19 +13,134 @@ #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; }; 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 ret; +} + +static int tensor_sec_update_bits(void *ctx, unsigned int reg, + unsigned int mask, unsigned int val) +{ + /* + * Use atomic operations for PMU_ALIVE registers (offset 0~0x3FFF) + * as the target registers can be accessed by multiple masters. + */ + if (reg > PMUALIVE_MASK) + 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 +191,41 @@ 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 regmap_config regmap_mmiocfg = { + .name = "pmu_regs", + .reg_bits = 32, + .reg_stride = 4, + .val_bits = 32, + .fast_io = true, + .use_single_read = true, + .use_single_write = true, +}; + +static const struct exynos_pmu_data gs101_pmu_data = { + .pmu_secure = 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 +259,75 @@ 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 + * @property: 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 exynos_pmu_context *ctx; + 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); + + ctx = dev_get_drvdata(dev); + + return ctx->pmureg; +} +EXPORT_SYMBOL_GPL(exynos_get_pmu_regmap_by_phandle); + 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 +339,38 @@ 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); + } else { + /* All other SoCs use a MMIO regmap */ + pmu_regmcfg = regmap_mmiocfg; + pmu_regmcfg.max_register = resource_size(res) - + pmu_regmcfg.reg_stride; + regmap = devm_regmap_init_mmio(dev, pmu_base_addr, + &pmu_regmcfg); + } + + if (IS_ERR(regmap)) + return dev_err_probe(&pdev->dev, PTR_ERR(regmap), + "regmap init failed\n"); + + pmu_context->pmureg = regmap; + pmu_context->dev = dev; + if (pmu_context->pmu_data && pmu_context->pmu_data->pmu_init) pmu_context->pmu_data->pmu_init(); diff --git a/drivers/soc/samsung/exynos-pmu.h b/drivers/soc/samsung/exynos-pmu.h index 1c652ffd79b4..0a49a2c9a08e 100644 --- a/drivers/soc/samsung/exynos-pmu.h +++ b/drivers/soc/samsung/exynos-pmu.h @@ -21,6 +21,7 @@ struct exynos_pmu_conf { struct exynos_pmu_data { const struct exynos_pmu_conf *pmu_config; const struct exynos_pmu_conf *pmu_config_extra; + bool pmu_secure; void (*pmu_init)(void); void (*powerdown_conf)(enum sys_powerdown); diff --git a/include/linux/soc/samsung/exynos-pmu.h b/include/linux/soc/samsung/exynos-pmu.h index a4f5516cc956..2bd9d12d9a52 100644 --- a/include/linux/soc/samsung/exynos-pmu.h +++ b/include/linux/soc/samsung/exynos-pmu.h @@ -10,6 +10,7 @@ #define __LINUX_SOC_EXYNOS_PMU_H struct regmap; +struct device_node; enum sys_powerdown { SYS_AFTR, @@ -20,12 +21,20 @@ enum sys_powerdown { extern void exynos_sys_powerdown_conf(enum sys_powerdown mode); #ifdef CONFIG_EXYNOS_PMU -extern struct regmap *exynos_get_pmu_regmap(void); +struct regmap *exynos_get_pmu_regmap(void); +struct regmap *exynos_get_pmu_regmap_by_phandle(struct device_node *np, + const char *propname); #else static inline struct regmap *exynos_get_pmu_regmap(void) { return ERR_PTR(-ENODEV); } + +static inline struct regmap *exynos_get_pmu_regmap_by_phandle(struct device_node *np, + const char *propname) +{ + return ERR_PTR(-ENODEV); +} #endif #endif /* __LINUX_SOC_EXYNOS_PMU_H */