Some SoCs need parts of their sram for special purposes. So while being part
of the peripheral, it should not be part of the genpool controlling the sram.
Therefore add an option available to keep arbitrary portions of the
sram from being part of the pool. If available is not present, all
sram is used.
Suggested-by: Rob Herring <robherring2@...>
move from marking reserved space to available space
Suggested-by: Matt Sealey <neko@...>
Signed-off-by: Heiko Stuebner <heiko@...>
Tested-by: Ulrich Prinz <ulrich.prinz@...>
Documentation/devicetree/bindings/misc/sram.txt | 8 ++++
drivers/misc/sram.c | 51 ++++++++++++++++++++---
2 files changed, 53 insertions(+), 6 deletions(-)
@@ -8,9 +8,17 @@ Required properties:
- reg : SRAM iomem address range
+Optional properties:
+
+- available: optional list of available chunks inside the sram that the
+ OS can use. Without available, the whole range is usable for the OS.
+ Format is <base size>, <base size>, ...; with base being relative to the
+ reg property base.
+
Example:
sram: sram@5c000000 {
compatible = "mmio-sram";
reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */
+ available = <0x100 0x3ff00>;
};
@@ -42,6 +42,8 @@ static int sram_probe(struct platform_device *pdev)
struct sram_dev *sram;
struct resource *res;
unsigned long size;
+ const __be32 *avail_list = NULL;
+ int avail_size = 0;
int ret;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -65,12 +67,49 @@ static int sram_probe(struct platform_device *pdev)
if (!sram->pool)
return -ENOMEM;
- ret = gen_pool_add_virt(sram->pool, (unsigned long)virt_base,
- res->start, size, -1);
- if (ret < 0) {
- if (sram->clk)
- clk_disable_unprepare(sram->clk);
- return ret;
+ if (pdev->dev.of_node) {
+ avail_list = of_get_property(pdev->dev.of_node,
+ "available",
+ &avail_size);
+ if (avail_list) {
+ avail_size /= sizeof(*avail_list);
+ if (!avail_size || avail_size % 2) {
+ dev_warn(&pdev->dev, "wrong number of arguments in available property\n");
+ avail_list = NULL;
+ }
+ }
+ }
+
+ if (!avail_list) {
+ ret = gen_pool_add_virt(sram->pool, (unsigned long)virt_base,
+ res->start, size, -1);
+ if (ret < 0) {
+ if (sram->clk)
+ clk_disable_unprepare(sram->clk);
+ return ret;
+ }
+ } else {
+ unsigned int astart;
+ unsigned int asize;
+ int i;
+
+ for (i = 0; i < avail_size; i += 2) {
+ /* get the next available block */
+ astart = be32_to_cpu(*avail_list++);
+ asize = be32_to_cpu(*avail_list++);
+
+ dev_dbg(&pdev->dev, "found available block 0x%x-0x%x\n",
+ astart, astart + asize);
+
+ ret = gen_pool_add_virt(sram->pool,
+ (unsigned long)virt_base + astart,
+ res->start + astart, asize, -1);
+ if (ret < 0) {
+ if (sram->clk)
+ clk_disable_unprepare(sram->clk);
+ return ret;
+ }
+ }
}
platform_set_drvdata(pdev, sram);