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Date: Mon, 29 Jul 2013 16:02:00 +0200
From: Philipp Zabel <p.zabel@...gutronix.de>
To: Heiko Stübner <heiko@...ech.de>
Cc: Arnd Bergmann <arnd@...db.de>, Olof Johansson <olof@...om.net>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
Grant Likely <grant.likely@...aro.org>,
Rob Herring <robherring2@...il.com>,
devicetree-discuss@...ts.ozlabs.org,
Russell King <linux@....linux.org.uk>,
linux-kernel@...r.kernel.org,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Ulrich Prinz <ulrich.prinz@...glemail.com>
Subject: Re: [PATCH v4 2/6] misc: sram: add ability to mark sram sections as
reserved
Hi Heiko,
Am Montag, den 29.07.2013, 15:12 +0200 schrieb Heiko Stübner:
> 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 mmio-sram-reserved to keep arbitrary portions of the
> sram from being part of the pool.
>
> Suggested-by: Rob Herring <robherring2@...il.com>
> Signed-off-by: Heiko Stuebner <heiko@...ech.de>
> Tested-by: Ulrich Prinz <ulrich.prinz@...glemail.com>
> ---
> Philipp: I didn't carry the ack, because the loop changed significantly again.
> So if it looks ok, could you re-ack it please?
I'd prefer the first loop to contain the magic and produce a list of
useable chunks, instead of a list of reserved blocks. The second loop
could then iterate over the array and just call gen_pool_add_virt
repeatedly.
regards
Philipp
> Documentation/devicetree/bindings/misc/sram.txt | 8 ++
> drivers/misc/sram.c | 101 +++++++++++++++++++++--
> 2 files changed, 101 insertions(+), 8 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/misc/sram.txt b/Documentation/devicetree/bindings/misc/sram.txt
> index 4d0a00e..3b7a5c1 100644
> --- a/Documentation/devicetree/bindings/misc/sram.txt
> +++ b/Documentation/devicetree/bindings/misc/sram.txt
> @@ -8,9 +8,17 @@ Required properties:
>
> - reg : SRAM iomem address range
>
> +Optional properties:
> +
> +- mmio-sram-reserved: ordered list of reserved chunks inside the sram that
> + should not be used by the OS.
> + Format is <base size>, <base size>, ...; with base being relative to the
> + reg property base.
> +
> Example:
>
> sram: sram@...00000 {
> compatible = "mmio-sram";
> reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */
> + mmio-sram-reserved = <0x0 0x100>; /* reserve 0x5c000000-0x5c000100 */
> };
> diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c
> index afe66571..b3ceefb 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 +75,94 @@ 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;
> + }
> +
> + for (i = 0; i < nblocks - 1; i++) {
> + rblocks[i].start = be32_to_cpu(*reserved_list++);
> + rblocks[i].size = be32_to_cpu(*reserved_list++);
> +
> + 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++) {
> + /* catch unsorted list entries */
> + 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;
> + }
> +
> + /* 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)
--
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