[PATCH 1/2] ARM: meson: Adding support to retrieve serial and SoC revision

[Carlo Caione]

On Wed, Feb 17, 2016 at 6:28 PM, Romain Perier <romain.perier at gmail.com> wrote:
> This path adds support to get the revision and the serial of the running
> SoC, on Meson8. On these plaforms, these informations can be found into

no Meson8b or Meson6?

> CBUS registers. To do so, we instanciate a syscon register, then create

What you mean with syscon register?

> a soc_device, and finally we expose everything to the system.
>
> Signed-off-by: Romain Perier <romain.perier at gmail.com>
> ---
>  arch/arm/mach-meson/meson.c | 55 +++++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 55 insertions(+)
>
> diff --git a/arch/arm/mach-meson/meson.c b/arch/arm/mach-meson/meson.c
> index 4e23571..2816e30 100644
> --- a/arch/arm/mach-meson/meson.c
> +++ b/arch/arm/mach-meson/meson.c
> @@ -13,8 +13,16 @@
>   *
>   */
>
> +#include <linux/of_address.h>
>  #include <linux/of_platform.h>
> +#include <linux/mfd/syscon.h>
> +#include <linux/regmap.h>
> +#include <linux/slab.h>
> +#include <linux/sys_soc.h>
>  #include <asm/mach/arch.h>
> +#include <asm/system_info.h>
> +
> +#define MESON_REVISION_REG (0x45c)
>
>  static const char * const meson_common_board_compat[] = {
>         "amlogic,meson6",
> @@ -23,7 +31,54 @@ static const char * const meson_common_board_compat[] = {
>         NULL,
>  };
>
> +static void __init meson_init_machine(void)
> +{
> +       struct soc_device_attribute *soc_dev_attr;
> +       struct soc_device *soc_dev;
> +       struct regmap *hwrev;
> +       unsigned int val;
> +       int ret;
> +
> +       hwrev = syscon_regmap_lookup_by_compatible("amlogic,meson8b-hwrev");

Is this specific only for Meson8b?

> +       if (IS_ERR(hwrev)) {
> +               pr_err("hwrev node not found\n");
> +               return;
> +       }
> +
> +       soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
> +       if (!soc_dev_attr)
> +               return;

Missing blank line

> +       ret = regmap_read(hwrev, 0, &val);
> +       if (ret < 0) {
> +               pr_err("Could not get SoC id\n");

kfree(soc_dev_attr)

> +               return;
> +       }
> +       system_serial_high = val << 24;
> +
> +       ret = regmap_read(hwrev, MESON_REVISION_REG, &val);
> +       if (ret < 0) {
> +               pr_err("Could not get SoC revision\n");

ditto

> +               return;
> +       }
> +       system_rev = val == 0x11111111 ? 0xA : 0xB;
> +
> +       soc_dev_attr->family = "Amlogic Meson";
> +       soc_dev_attr->revision = kasprintf(GFP_KERNEL, "0x%x", system_rev);
> +       soc_dev_attr->soc_id = kasprintf(GFP_KERNEL, "0x%x", system_serial_high);
> +
> +       soc_dev = soc_device_register(soc_dev_attr);
> +       if (IS_ERR(soc_dev)) {
> +               pr_err("Could not register soc device\n");
> +               kfree(soc_dev_attr);

leaking soc_dev_attr->revision and  soc_dev_attr->soc_id also any
reason why you are not kasprintf-ing also family?

> +               return;
> +       }
> +
> +       pr_info("Amlogic Meson SoC Rev%X (%X:%X)\n", system_rev, system_serial_high, system_rev);
> +       of_platform_populate(NULL, of_default_bus_match_table, NULL, soc_dev);

Compiling I got:

  CC      arch/arm/mach-meson/meson.o
arch/arm/mach-meson/meson.c: In function 'meson_init_machine':
arch/arm/mach-meson/meson.c:77:63: warning: passing argument 4 of
'of_platform_populate' from incompatible pointer type
  of_platform_populate(NULL, of_default_bus_match_table, NULL, soc_dev);
                                                               ^
In file included from arch/arm/mach-meson/meson.c:17:0:
include/linux/of_platform.h:71:12: note: expected 'struct device *'
but argument is of type 'struct soc_device *'
 extern int of_platform_populate(struct device_node *root,
            ^

> +}
> +
>  DT_MACHINE_START(MESON, "Amlogic Meson platform")
> +       .init_machine   = meson_init_machine,

Uhm, you are assuming that this code is valid for Meson8, Meson8b and
also Meson6. Are you sure about that?

>         .dt_compat      = meson_common_board_compat,
>         .l2c_aux_val    = 0,
>         .l2c_aux_mask   = ~0,
> --
> 2.5.0

Thanks for working on this!

-- 
Carlo Caione