Messages in this thread | | | From | Heiko Stübner <> | Subject | Re: [PATCH v2 2/6] misc: sram: add ability to mark sram sections as reserved | Date | Wed, 26 Jun 2013 11:18:43 +0200 |
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Hi Philipp,
Am Dienstag, 25. Juni 2013, 12:17:05 schrieb Philipp Zabel: > Hi Heiko, > > Am Dienstag, den 25.06.2013, 10:47 +0200 schrieb Heiko Stübner: > > Some SoCs need parts of their sram for special purposes. So while being > > part of the periphal, it should not be part of the genpool controlling > > the sram. > > > > Threfore add an option mmio-sram-reserved to keep arbitary 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> > > --- > > > > Documentation/devicetree/bindings/misc/sram.txt | 8 +++ > > drivers/misc/sram.c | 86 > > +++++++++++++++++++++-- 2 files changed, 88 insertions(+), 6 > > deletions(-) > > > > diff --git a/Documentation/devicetree/bindings/misc/sram.txt > > b/Documentation/devicetree/bindings/misc/sram.txt index 4d0a00e..eae080e > > 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 become part of the genalloc pool. > > + Format is <base size>, <base size>, ...; with base being relative to > > the + reg property base. > > + > > the keyword to reserve blocks of ram is /memreserve/ - should this > property name be aligned with that?
The mmio-sram-reserved name was suggested by Rob Herring, who I suppose has some slight experience with devicetree :-) .
I wasn't able to find real documentation on /memreserve/ but it looks more like it's used to reserve generic memregions, not being node-specific. So reusing this might also cause confusion when the reserve-data now is relative to it's node reg.
> > 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..5fccbe3 100644 > > --- a/drivers/misc/sram.c > > +++ b/drivers/misc/sram.c > > @@ -42,6 +42,8 @@ static int sram_probe(struct platform_device *pdev) > > > > struct sram_dev *sram; > > struct resource *res; > > unsigned long size; > > > > + const __be32 *reserved_list = NULL; > > + int reserved_size = 0; > > > > int ret; > > > > res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > > > > @@ -65,12 +67,89 @@ 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; > > + } > > + } > > + } > > + > > + if (!reserved_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; > > + } > > Moving the clk_prepare_enable() further down would allow to avoid the > clk_disable_unprepare() in every error path, > > > + } else { > > + unsigned int cur_start = 0; > > + unsigned int cur_size; > > + unsigned int rstart; > > + unsigned int rsize; > > + int i; > > + > > + for (i = 0; i < reserved_size; i += 2) { > > + /* get the next reserved block */ > > + rstart = be32_to_cpu(*reserved_list++); > > + rsize = be32_to_cpu(*reserved_list++); > > + > > + /* catch unsorted list entries */ > > + if (rstart < cur_start) { > > + dev_err(&pdev->dev, "unsorted reserved list (0x%x before current > > 0x%x)\n", + rstart, cur_start); > > + if (sram->clk) > > + clk_disable_unprepare(sram->clk); > > like here > > > + return -EINVAL; > > + } > > + > > + dev_dbg(&pdev->dev, "found reserved block 0x%x-0x%x\n", > > + rstart, rstart + rsize); > > + > > + /* current start is in a reserved block */ > > + if (rstart <= cur_start) { > > + cur_start = rstart + rsize; > > + continue; > > + } > > + > > + /* > > + * allocate the space between the current starting > > + * address and the following reserved block > > + */ > > + cur_size = rstart - cur_start; > > + > > + dev_dbg(&pdev->dev, "adding chunk 0x%x-0x%x\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) { > > + if (sram->clk) > > + clk_disable_unprepare(sram->clk); > > and here. > > > + return ret; > > + } > > + > > + /* next allocation after this reserved block */ > > + cur_start = rstart + rsize; > > + } > > + > > + /* allocate the space after the last reserved block */ > > + if (cur_start < size) { > > + cur_size = size - cur_start; > > + > > + dev_dbg(&pdev->dev, "adding chunk 0x%x-0x%x\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); > > + } > > + > > > > } > > > > platform_set_drvdata(pdev, sram); > > Also, I think you could reduce the duplication of gen_pool_add_virt() > function calls, somehow like this: > > unsigned int cur_start = 0; > unsigned int cur_size; > unsigned int rstart; > unsigned int rsize; > int i = 0; > > if (!reserved_list) > reserved_size = 0; > > for (i = 0; i < (reserved_size + 2); i += 2) { > if (i < reserved_size) { > /* get the next reserved block */ > rstart = be32_to_cpu(*reserved_list++); > rsize = be32_to_cpu(*reserved_list++); > > /* catch unsorted list entries */ > if (rstart < cur_start) { > dev_err(&pdev->dev, > "unsorted reserved list (0x%x before current 0x%x)\n", > rstart, cur_start); > return -EINVAL; > } > > dev_dbg(&pdev->dev, > "found reserved block 0x%x-0x%x\n", > rstart, rstart + rsize); > } else { > /* the last chunk extends to the end of the region */ > rstart = size; > } > > /* current start is in a reserved block */ > if (rstart <= cur_start) { > cur_start = rstart + rsize; > continue; > } > > /* > * allocate the space between the current starting > * address and the following reserved block, or the > * end of the region. > */ > cur_size = rstart - cur_start; > > dev_dbg(&pdev->dev, "adding chunk 0x%x-0x%x\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) > return ret; > }
yep, this looks nicer - same for moving the clk_prepare_enable to below this loop to unclutter the error-path.
So I will incorporate this in v3.
Thanks Heiko -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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