Messages in this thread | | | Subject | Re: [PATCH v4 2/6] misc: sram: add ability to mark sram sections as reserved | From | Philipp Zabel <> | Date | Mon, 29 Jul 2013 16:02:00 +0200 |
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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@gmail.com> > Signed-off-by: Heiko Stuebner <heiko@sntech.de> > Tested-by: Ulrich Prinz <ulrich.prinz@googlemail.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@5c000000 { > 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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