From mboxrd@z Thu Jan 1 00:00:00 1970 From: Philipp Zabel Subject: Re: [PATCH v2 2/6] misc: sram: add ability to mark sram sections as reserved Date: Tue, 25 Jun 2013 12:17:05 +0200 Message-ID: <1372155425.3981.67.camel@pizza.hi.pengutronix.de> References: <201306251046.04873.heiko@sntech.de> <201306251047.12899.heiko@sntech.de> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <201306251047.12899.heiko@sntech.de> Sender: linux-kernel-owner@vger.kernel.org To: Heiko =?ISO-8859-1?Q?St=FCbner?= Cc: Arnd Bergmann , Olof Johansson , "linux-arm-kernel@lists.infradead.org" , Grant Likely , Rob Herring , devicetree-discuss@lists.ozlabs.org, Russell King , linux-kernel@vger.kernel.org, Greg Kroah-Hartman List-Id: devicetree@vger.kernel.org Hi Heiko, Am Dienstag, den 25.06.2013, 10:47 +0200 schrieb Heiko St=C3=BCbner: > Some SoCs need parts of their sram for special purposes. So while bei= ng part > of the periphal, it should not be part of the genpool controlling the= sram. >=20 > Threfore add an option mmio-sram-reserved to keep arbitary portions o= f the > sram from being part of the pool. >=20 > Suggested-by: Rob Herring > Signed-off-by: Heiko Stuebner > --- > Documentation/devicetree/bindings/misc/sram.txt | 8 +++ > drivers/misc/sram.c | 86 +++++++++++++= ++++++++-- > 2 files changed, 88 insertions(+), 6 deletions(-) >=20 > diff --git a/Documentation/devicetree/bindings/misc/sram.txt b/Docume= ntation/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: > =20 > - reg : SRAM iomem address range > =20 > +Optional properties: > + > +- mmio-sram-reserved: ordered list of reserved chunks inside the sra= m that > + should not become part of the genalloc pool. > + Format is , , ...; 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? > Example: > =20 > sram: sram@5c000000 { > compatible =3D "mmio-sram"; > reg =3D <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000= */ > + mmio-sram-reserved =3D <0x0 0x100>; /* reserve 0x5c000000-0x5c00010= 0 */ > }; > 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 =3D NULL; > + int reserved_size =3D 0; > int ret; > =20 > res =3D platform_get_resource(pdev, IORESOURCE_MEM, 0); > @@ -65,12 +67,89 @@ static int sram_probe(struct platform_device *pde= v) > if (!sram->pool) > return -ENOMEM; > =20 > - ret =3D 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 =3D of_get_property(pdev->dev.of_node, > + "mmio-sram-reserved", > + &reserved_size); > + if (reserved_list) { > + reserved_size /=3D sizeof(*reserved_list); > + if (!reserved_size || reserved_size % 2) { > + dev_warn(&pdev->dev, "wrong number of arguments in mmio-sram-res= erved\n"); > + reserved_list =3D NULL; > + } > + } > + } > + > + if (!reserved_list) { > + ret =3D 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 =3D 0; > + unsigned int cur_size; > + unsigned int rstart; > + unsigned int rsize; > + int i; > + > + for (i =3D 0; i < reserved_size; i +=3D 2) { > + /* get the next reserved block */ > + rstart =3D be32_to_cpu(*reserved_list++); > + rsize =3D 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 <=3D cur_start) { > + cur_start =3D rstart + rsize; > + continue; > + } > + > + /* > + * allocate the space between the current starting > + * address and the following reserved block > + */ > + cur_size =3D rstart - cur_start; > + > + dev_dbg(&pdev->dev, "adding chunk 0x%x-0x%x\n", > + cur_start, cur_start + cur_size); > + ret =3D 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 =3D rstart + rsize; > + } > + > + /* allocate the space after the last reserved block */ > + if (cur_start < size) { > + cur_size =3D size - cur_start; > + > + dev_dbg(&pdev->dev, "adding chunk 0x%x-0x%x\n", > + cur_start, cur_start + cur_size); > + ret =3D gen_pool_add_virt(sram->pool, > + (unsigned long)virt_base + cur_start, > + res->start + cur_start, cur_size, -1); > + } > + > } > =20 > 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 =3D 0; unsigned int cur_size; unsigned int rstart; unsigned int rsize; int i =3D 0; if (!reserved_list) reserved_size =3D 0; for (i =3D 0; i < (reserved_size + 2); i +=3D 2) { if (i < reserved_size) { /* get the next reserved block */ rstart =3D be32_to_cpu(*reserved_list++); rsize =3D 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 =3D size; } /* current start is in a reserved block */ if (rstart <=3D cur_start) { cur_start =3D rstart + rsize; continue; } /* * allocate the space between the current starting * address and the following reserved block, or the * end of the region. */ cur_size =3D rstart - cur_start; dev_dbg(&pdev->dev, "adding chunk 0x%x-0x%x\n", cur_start, cur_start + cur_size); ret =3D gen_pool_add_virt(sram->pool, (unsigned long)virt_base + cur_start, res->start + cur_start, cur_size, -1); if (ret < 0) return ret; } regards Philipp