Hi Alexandre,
Am Mittwoch, den 31.08.2016, 18:11 +0200 schrieb Alexandre Belloni:
> The Atmel secure SRAM is connected to a security module and may be erased
> automatically under certain conditions. For that reason, it is necessary to
> wait for the security module to flag that SRAM accesses are allowed before
> accessing it.
>
> Signed-off-by: Alexandre Belloni <[email protected]>
> ---
> Cc: Arnd Bergmann <[email protected]>
> Cc: Greg Kroah-Hartman <[email protected]>
> Cc: Philipp Zabel <[email protected]>
> Cc: Vladimir Zapolskiy <[email protected]>
> drivers/misc/sram.c | 52 +++++++++++++++++++++++++++++++++++++++++++++-------
> 1 file changed, 45 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c
> index f84b53d6ce50..8d411c64d07f 100644
> --- a/drivers/misc/sram.c
> +++ b/drivers/misc/sram.c
> @@ -19,12 +19,16 @@
> */
>
> #include <linux/clk.h>
> +#include <linux/delay.h>
> #include <linux/genalloc.h>
> #include <linux/io.h>
> #include <linux/list_sort.h>
> #include <linux/of_address.h>
> #include <linux/platform_device.h>
> +#include <linux/regmap.h>
> #include <linux/slab.h>
> +#include <linux/mfd/syscon.h>
> +#include <soc/at91/atmel-secumod.h>
>
> #define SRAM_GRANULARITY 32
>
> @@ -334,12 +338,43 @@ static int sram_reserve_regions(struct sram_dev *sram,
> struct resource *res)
> return ret;
> }
>
> +static int atmel_securam_wait(void)
> +{
> + struct regmap *regmap;
> + unsigned long timeout = jiffies + HZ;
Can this really take up to a second?
> + u32 val;
> +
> + regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-secumod");
> + if (IS_ERR(regmap))
> + return -ENODEV;
> +
> + regmap_read(regmap, AT91_SECUMOD_RAMRDY, &val);
> + while (!(val & AT91_SECUMOD_RAMRDY_READY) &&
> + time_before(jiffies, timeout)) {
> + mdelay(10);
> + regmap_read(regmap, AT91_SECUMOD_RAMRDY, &val);
> + }
> + if (!time_before(jiffies, timeout))
> + return -ETIMEDOUT;
> +
> + return 0;
Could you use regmap_read_poll_timeout here?
> +}
> +
> +#ifdef CONFIG_OF
> +static const struct of_device_id sram_dt_ids[] = {
> + { .compatible = "mmio-sram" },
> + { .compatible = "atmel,sama5d2-securam", .data = atmel_securam_wait },
> + {}
> +};
> +#endif
> +
> static int sram_probe(struct platform_device *pdev)
> {
> struct sram_dev *sram;
> struct resource *res;
> size_t size;
> int ret;
> + const struct of_device_id *match;
>
> sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL);
> if (!sram)
> @@ -384,6 +419,16 @@ static int sram_probe(struct platform_device *pdev)
>
> platform_set_drvdata(pdev, sram);
>
> + match = of_match_node(sram_dt_ids, pdev->dev.of_node);
> + if (match->data) {
And of_device_get_match_data here?
> + int (*init_func)(void);
> +
> + init_func = match->data;
> + ret = init_func();
> + if (ret)
> + return ret;
> + }
> +
> dev_dbg(sram->dev, "SRAM pool: %zu KiB @ 0x%p\n",
> gen_pool_size(sram->pool) / 1024, sram->virt_base);
>
> @@ -405,13 +450,6 @@ static int sram_remove(struct platform_device *pdev)
> return 0;
> }
>
> -#ifdef CONFIG_OF
> -static const struct of_device_id sram_dt_ids[] = {
> - { .compatible = "mmio-sram" },
> - {}
> -};
> -#endif
> -
> static struct platform_driver sram_driver = {
> .driver = {
> .name = "sram",
regards
Philipp
