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: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c
index f84b53d..b0d4dd9 100644
--- a/drivers/misc/sram.c
+++ b/drivers/misc/sram.c
@@ -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 @@
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 @@
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 @@
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",