[PATCH v6 2/6] misc: sram: implement mmio-sram-reserved option

Heiko Stübner
2014-01-15T21:42:05Z

This implements support for the mmio-sram-reserved option to keep the
genpool from using these areas.

Suggested-by: Rob Herring <robherring2@gmail.com>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
Tested-by: Ulrich Prinz <ulrich.prinz@googlemail.com>
---
drivers/misc/sram.c | 118 +++++++++++++++++++++++++++++++++++++++++++++++----
1 file changed, 110 insertions(+), 8 deletions(-)

diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c
index afe66571..7fb60f3 100644
--- a/drivers/misc/sram.c
+++ b/drivers/misc/sram.c
@@ -36,13 +36,23 @@ struct sram_dev {
struct clk *clk;
};

+struct sram_reserve {
+ unsigned long start;
+ unsigned long size;
+};
+
static int sram_probe(struct platform_device *pdev)
{
void __iomem *virt_base;
struct sram_dev *sram;
struct resource *res;
- unsigned long size;
- int ret;
+ unsigned long size, cur_start, cur_size;
+ const __be32 *reserved_list = NULL;
+ int reserved_size = 0;
+ struct sram_reserve *rblocks;
+ unsigned int nblocks;
+ int ret = 0;
+ int i;

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
virt_base = devm_ioremap_resource(&pdev->dev, res);
@@ -65,19 +75,111 @@ 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) {
+ reserved_list = of_get_property(pdev->dev.of_node,
+ "mmio-sram-reserved",
+ &reserved_size);
+ if (reserved_list) {
+ reserved_size /= sizeof(*reserved_list);
+ if (!reserved_size || reserved_size % 2) {
+ dev_warn(&pdev->dev, "wrong number of arguments in mmio-sram-reserved\n");
+ reserved_list = NULL;
+ reserved_size = 0;
+ }
+ }
+ }
+
+ /*
+ * We need an additional block to mark the end of the memory region
+ * after the reserved blocks from the dt are processed.
+ */
+ nblocks = reserved_size / 2 + 1;
+ rblocks = kmalloc((nblocks) * sizeof(*rblocks), GFP_KERNEL);
+ if (!rblocks) {
+ ret = -ENOMEM;
+ goto err_alloc;
+ }
+
+ cur_start = 0;
+ for (i = 0; i < nblocks - 1; i++) {
+ rblocks[i].start = be32_to_cpu(*reserved_list++);
+ rblocks[i].size = be32_to_cpu(*reserved_list++);
+
+ if (rblocks[i].start < cur_start) {
+ dev_err(&pdev->dev,
+ "unsorted reserved list (0x%lx before current 0x%lx)\n",
+ rblocks[i].start, cur_start);
+ ret = -EINVAL;
+ goto err_chunks;
+ }
+
+ if (rblocks[i].start >= size) {
+ dev_err(&pdev->dev,
+ "reserved block at 0x%lx outside the sram size 0x%lx\n",
+ rblocks[i].start, size);
+ ret = -EINVAL;
+ goto err_chunks;
+ }
+
+ if (rblocks[i].start + rblocks[i].size > size) {
+ dev_warn(&pdev->dev,
+ "reserved block at 0x%lx to large, trimming\n",
+ rblocks[i].start);
+ rblocks[i].size = size - rblocks[i].start;
+ }
+
+ cur_start = rblocks[i].start + rblocks[i].size;
+
+ dev_dbg(&pdev->dev, "found reserved block 0x%lx-0x%lx\n",
+ rblocks[i].start,
+ rblocks[i].start + rblocks[i].size);
+ }
+
+ /* the last chunk marks the end of the region */
+ rblocks[nblocks - 1].start = size;
+ rblocks[nblocks - 1].size = 0;
+
+ cur_start = 0;
+ for (i = 0; i < nblocks; i++) {
+ /* current start is in a reserved block, so continue after it */
+ if (rblocks[i].start == cur_start) {
+ cur_start = rblocks[i].start + rblocks[i].size;
+ continue;
+ }
+
+ /*
+ * allocate the space between the current starting
+ * address and the following reserved block, or the
+ * end of the region.
+ */
+ cur_size = rblocks[i].start - cur_start;
+
+ dev_dbg(&pdev->dev, "adding chunk 0x%lx-0x%lx\n",
+ cur_start, cur_start + cur_size);
+ ret = gen_pool_add_virt(sram->pool,
+ (unsigned long)virt_base + cur_start,
+ res->start + cur_start, cur_size, -1);
+ if (ret < 0)
+ goto err_chunks;
+
+ /* next allocation after this reserved block */
+ cur_start = rblocks[i].start + rblocks[i].size;
}

+ kfree(rblocks);
+
platform_set_drvdata(pdev, sram);

dev_dbg(&pdev->dev, "SRAM pool: %ld KiB @ 0x%p\n", size / 1024, virt_base);

return 0;
+
+err_chunks:
+ kfree(rblocks);
+err_alloc:
+ if (sram->clk)
+ clk_disable_unprepare(sram->clk);
+ return ret;
}

static int sram_remove(struct platform_device *pdev)
--
1.7.10.4