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Commit 2ae2e288 authored by Alexandre Belloni's avatar Alexandre Belloni
Browse files

misc: sram: add Atmel securam support 



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: default avatarAlexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 15adffad

drivers/misc/sram.c

+35 −7
Original line number Diff line number Diff line
@@ -19,12 +19,17 @@ 
 */



#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/of_device.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 +339,35 @@ static int sram_reserve_regions(struct sram_dev *sram, struct resource *res) 
	return ret;

}



static int atmel_securam_wait(void)

{

	struct regmap *regmap;

	u32 val;



	regmap = syscon_regmap_lookup_by_compatible("atmel,sama5d2-secumod");

	if (IS_ERR(regmap))

		return -ENODEV;



	return regmap_read_poll_timeout(regmap, AT91_SECUMOD_RAMRDY, val,

					val & AT91_SECUMOD_RAMRDY_READY,

					10000, 500000);

}



#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;

	int (*init_func)(void);



	sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL);

	if (!sram)
@@ -384,6 +412,13 @@ static int sram_probe(struct platform_device *pdev) 


	platform_set_drvdata(pdev, sram);



	init_func = of_device_get_match_data(&pdev->dev);

	if (init_func) {

		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 +440,6 @@ 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",