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Date: Sun, 27 Apr 2014 16:29:42 +0900
From: Pankaj Dubey <pankaj.dubey@...sung.com>
To: Tomasz Figa <tomasz.figa@...il.com>
Cc: linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, 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 Tomasz,
Thanks for review.
On 04/26/2014 06:43 AM, Tomasz Figa wrote:
> 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?
Well, currently "get_exynos_pmuregmap" is used in three location under
mach-exynos as "exynos.c", "pm.c" and "hotplug.c" so just to avoid duplicate code
in all these files I added "get_exynos_pmuregmap" as helper function in "exynos.c".
So in my opinion it should be fine. What do you say?
Regarding "get_exynos_pmuaddr", only user of this function is "platsmp.c" so I can
move this function in platsmp.c and remove this helper. This will also solve the
other
issue of early mapping as you raised below.
>
>> +
>> #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?
OK, not really required, If I move mapping of PMU base address to platsmp.c.
As "exynos_pmu_base" is only required in platsmp.c during "exynos_smp_prepare_cpus"
function call, I can move mapping of PMU address in platsmp.c itself and there I
can use of_iomap.
>
>> +
>> /*
>> * 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.)
OK, will remove "get_exynos_pmuaddr" and make "get_exynos_pmuregmap" as
non-static non-inline.
>
>> +
>> +
>> +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.
>
Yes, as "exynos_restart" is accessing one PMU register. So even though all callers
(pm.c and hotplug.c) directly retrieve a regmap handle to PMU, we need regmap handle
in this file also. So as I mentioned above just to avoid duplicate code in all
files we can
retrieve regmap handle in "exynos.c" and using helper function other files can
use it.
> Best regards,
> Tomasz
>
--
Best Regards,
Pankaj Dubey
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