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Date: Fri, 25 Apr 2014 23:43:43 +0200
From: Tomasz Figa <tomasz.figa@...il.com>
To: Pankaj Dubey <pankaj.dubey@...sung.com>,
linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org
CC: kgene.kim@...sung.com, linux@....linux.org.uk, t.figa@...sung.com,
chow.kim@...sung.com, yg1004.jang@...sung.com,
vikas.sajjan@...sung.com, s.nawrocki@...sung.com,
b.zolnierkie@...sung.com
Subject: Re: [PATCH v2 06/10] ARM: EXYNOS: Add support for mapping PMU base
address via DT
Hi,
On 25.04.2014 14:32, Pankaj Dubey wrote:
> From: Young-Gun Jang <yg1004.jang@...sung.com>
>
> Add support for mapping Samsung Power Management Unit (PMU) base address
> from device tree. Code will use existing samsung pmu binding information.
> This patch also adds two helper functions as "get_exynos_pmuregmap" and
> "get_exynos_pmuaddr".
> "get_exynos_pmuregmap" returns a regmap based PMU register handle where as
> "get_exynos_pmuaddr" returns ioremap virtual address.
>
> Signed-off-by: Young-Gun Jang <yg1004.jang@...sung.com>
> Signed-off-by: Pankaj Dubey <pankaj.dubey@...sung.com>
> ---
> arch/arm/mach-exynos/Kconfig | 2 ++
> arch/arm/mach-exynos/common.h | 3 ++
> arch/arm/mach-exynos/exynos.c | 78 +++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 83 insertions(+)
>
> diff --git a/arch/arm/mach-exynos/Kconfig b/arch/arm/mach-exynos/Kconfig
> index fc8bf18..2f60c90 100644
> --- a/arch/arm/mach-exynos/Kconfig
> +++ b/arch/arm/mach-exynos/Kconfig
> @@ -26,6 +26,7 @@ config ARCH_EXYNOS4
> select PINCTRL
> select PM_GENERIC_DOMAINS if PM_RUNTIME
> select S5P_DEV_MFC
> + select MFD_SYSCON
> help
> Samsung EXYNOS4 SoCs based systems
>
> @@ -36,6 +37,7 @@ config ARCH_EXYNOS5
> select HAVE_ARM_SCU if SMP
> select HAVE_SMP
> select PINCTRL
> + select MFD_SYSCON
> help
> Samsung EXYNOS5 (Cortex-A15) SoC based systems
>
> diff --git a/arch/arm/mach-exynos/common.h b/arch/arm/mach-exynos/common.h
> index 31c5964..ecfd0fc 100644
> --- a/arch/arm/mach-exynos/common.h
> +++ b/arch/arm/mach-exynos/common.h
> @@ -57,4 +57,7 @@ struct exynos_pmu_conf {
>
> extern void exynos_sys_powerdown_conf(enum sys_powerdown mode);
>
> +extern struct regmap *get_exynos_pmuregmap(void);
> +extern void __iomem *get_exynos_pmuaddr(void);
Do you really need these functions? Couldn't all the drivers using PMU
simply call syscon_regmap_lookup_by_phandle() or of_iomap() directly?
> +
> #endif /* __ARCH_ARM_MACH_EXYNOS_COMMON_H */
> diff --git a/arch/arm/mach-exynos/exynos.c b/arch/arm/mach-exynos/exynos.c
> index d6f405f..68f60e1 100644
> --- a/arch/arm/mach-exynos/exynos.c
> +++ b/arch/arm/mach-exynos/exynos.c
> @@ -19,6 +19,7 @@
> #include <linux/of_platform.h>
> #include <linux/platform_device.h>
> #include <linux/pm_domain.h>
> +#include <linux/mfd/syscon.h>
>
> #include <asm/cacheflush.h>
> #include <asm/hardware/cache-l2x0.h>
> @@ -36,6 +37,9 @@
> #define L2_AUX_VAL 0x7C470001
> #define L2_AUX_MASK 0xC200ffff
>
> +static struct regmap *exynos_pmu_regmap;
> +static void __iomem *exynos_pmu_base;
> +
> static struct map_desc exynos4_iodesc[] __initdata = {
> {
> .virtual = (unsigned long)S3C_VA_SYS,
> @@ -269,6 +273,46 @@ static int __init exynos_fdt_map_chipid(unsigned long node, const char *uname,
> return 1;
> }
>
> +static const struct of_device_id exynos_dt_pmu_match[] = {
> + { .compatible = "samsung,exynos4210-pmu" },
> + { .compatible = "samsung,exynos4212-pmu" },
> + { .compatible = "samsung,exynos4412-pmu" },
> + { .compatible = "samsung,exynos5250-pmu" },
> + {},
> +};
> +
> +static int __init exynos_fdt_map_pmu(unsigned long node,
> + const char *uname, int depth, void *data)
> +{
> + struct map_desc iodesc;
> + __be32 *reg;
> + unsigned long len;
> + phys_addr_t phys_addr;
> + const struct of_device_id *matches = exynos_dt_pmu_match;
> +
> + for (; matches->compatible[0]; matches++) {
> + if (!of_flat_dt_is_compatible(node, matches->compatible))
> + continue;
> + reg = of_get_flat_dt_prop(node, "reg", &len);
> + if (reg == NULL || len != (sizeof(unsigned long) * 2))
> + return 0;
> +
> + phys_addr = be32_to_cpu(reg[0]);
> + iodesc.pfn = __phys_to_pfn(phys_addr);
> + iodesc.length = be32_to_cpu(reg[1]) - 1;
> + iodesc.virtual = (unsigned long)S5P_VA_PMU;
> + iodesc.type = MT_DEVICE;
> + iotable_init(&iodesc, 1);
> +
> + exynos_pmu_base = ioremap(phys_addr, be32_to_cpu(reg[1]));
> + if (WARN_ON(!exynos_pmu_base))
> + return -EFAULT;
> + return 1;
> + }
> +
> + return 0;
> +}
Is such early mapping really needed? Couldn't the code using PMU be
deferred to the stage that memory management is available and then
of_iomap() used directly?
> +
> /*
> * exynos_map_io
> *
> @@ -302,6 +346,7 @@ static void __init exynos_init_io(void)
> debug_ll_io_init();
>
> of_scan_flat_dt(exynos_fdt_map_chipid, NULL);
> + of_scan_flat_dt(exynos_fdt_map_pmu, NULL);
>
> /* detect cpu id and rev. */
> s5p_init_cpu(S5P_VA_CHIPID);
> @@ -336,6 +381,38 @@ static int __init exynos4_l2x0_cache_init(void)
> }
> early_initcall(exynos4_l2x0_cache_init);
>
> +
> +inline struct regmap *get_exynos_pmuregmap()
> +{
> + return exynos_pmu_regmap;
> +}
> +
> +inline void __iomem *get_exynos_pmuaddr()
> +{
> + return exynos_pmu_base;
> +}
Hmm, non-static inline inside a C file? Probably should be either static
inline or non-static non-inline. (Assuming that both are really needed,
as I pointed in the comments above.)
> +
> +
> +void __init exynos_map_pmu(void)
> +{
> + struct device_node *np = NULL;
> +
> + early_syscon_init();
> +
> + np = of_find_matching_node(NULL, exynos_dt_pmu_match);
> +
> + if (!np) {
> + pr_err("Failed to find PMU node\n");
> + return;
> + } else {
> + exynos_pmu_regmap = syscon_early_regmap_lookup_by_phandle(np,
> + "samsung,syscon-phandle");
Do you need this regmap really here? I believe it should be the code
using PMU registers which calls this function directly to retrieve a
handle to the syscon.
Best regards,
Tomasz
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