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SubjectRe: [PATCH v8 2/6] misc: sram: implement reserved sram areas
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Hi Heiko,

Am Dienstag, den 25.02.2014, 12:46 +0100 schrieb Heiko Stübner:
> This implements support for defining reserved areas as subnodes,
> to keep the genpool from using these.
>
> Suggested-by: Rob Herring <robherring2@gmail.com>
> Signed-off-by: Heiko Stuebner <heiko@sntech.de>
> Tested-by: Ulrich Prinz <ulrich.prinz@googlemail.com>

Acked-by: Philipp Zabel <p.zabel@pengutronix.de>

> ---
> drivers/misc/sram.c | 125 +++++++++++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 118 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c
> index afe66571..674b0cd 100644
> --- a/drivers/misc/sram.c
> +++ b/drivers/misc/sram.c
> @@ -24,6 +24,9 @@
> #include <linux/err.h>
> #include <linux/io.h>
> #include <linux/of.h>
> +#include <linux/of_address.h>
> +#include <linux/list.h>
> +#include <linux/list_sort.h>
> #include <linux/platform_device.h>
> #include <linux/slab.h>
> #include <linux/spinlock.h>
> @@ -36,14 +39,35 @@ struct sram_dev {
> struct clk *clk;
> };
>
> +struct sram_reserve {
> + struct list_head list;
> + u32 start;
> + u32 size;
> +};
> +
> +static int sram_reserve_cmp(void *priv, struct list_head *a,
> + struct list_head *b)
> +{
> + struct sram_reserve *ra = list_entry(a, struct sram_reserve, list);
> + struct sram_reserve *rb = list_entry(b, struct sram_reserve, list);
> +
> + return ra->start - rb->start;
> +}
> +
> static int sram_probe(struct platform_device *pdev)
> {
> void __iomem *virt_base;
> struct sram_dev *sram;
> struct resource *res;
> - unsigned long size;
> + struct device_node *np = pdev->dev.of_node, *child;
> + unsigned long size, cur_start, cur_size;
> + struct sram_reserve *rblocks, *block;
> + struct list_head reserve_list;
> + unsigned int nblocks;
> int ret;
>
> + INIT_LIST_HEAD(&reserve_list);
> +
> res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> virt_base = devm_ioremap_resource(&pdev->dev, res);
> if (IS_ERR(virt_base))
> @@ -65,19 +89,106 @@ 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;
> + /*
> + * We need an additional block to mark the end of the memory region
> + * after the reserved blocks from the dt are processed.
> + */
> + nblocks = (np) ? of_get_available_child_count(np) + 1 : 1;
> + rblocks = kmalloc((nblocks) * sizeof(*rblocks), GFP_KERNEL);
> + if (!rblocks) {
> + ret = -ENOMEM;
> + goto err_alloc;
> }
>
> + block = &rblocks[0];
> + for_each_available_child_of_node(np, child) {
> + struct resource child_res;
> +
> + ret = of_address_to_resource(child, 0, &child_res);
> + if (ret < 0) {
> + dev_err(&pdev->dev,
> + "could not get address for node %s\n",
> + child->full_name);
> + goto err_chunks;
> + }
> +
> + if (child_res.start < res->start || child_res.end > res->end) {
> + dev_err(&pdev->dev,
> + "reserved block %s outside the sram area\n",
> + child->full_name);
> + ret = -EINVAL;
> + goto err_chunks;
> + }
> +
> + block->start = child_res.start - res->start;
> + block->size = resource_size(&child_res);
> + list_add_tail(&block->list, &reserve_list);
> +
> + dev_dbg(&pdev->dev, "found reserved block 0x%x-0x%x\n",
> + block->start,
> + block->start + block->size);
> +
> + block++;
> + }
> +
> + /* the last chunk marks the end of the region */
> + rblocks[nblocks - 1].start = size;
> + rblocks[nblocks - 1].size = 0;
> + list_add_tail(&rblocks[nblocks - 1].list, &reserve_list);
> +
> + list_sort(NULL, &reserve_list, sram_reserve_cmp);
> +
> + cur_start = 0;
> +
> + list_for_each_entry(block, &reserve_list, list) {
> + /* can only happen if sections overlap */
> + if (block->start < cur_start) {
> + dev_err(&pdev->dev,
> + "block at 0x%x starts after current offset 0x%lx\n",
> + block->start, cur_start);
> + ret = -EINVAL;
> + goto err_chunks;
> + }
> +
> + /* current start is in a reserved block, so continue after it */
> + if (block->start == cur_start) {
> + cur_start = block->start + block->size;
> + continue;
> + }
> +
> + /*
> + * allocate the space between the current starting
> + * address and the following reserved block, or the
> + * end of the region.
> + */
> + cur_size = block->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 = block->start + block->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)

regards
Philipp

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