| Message ID | 20121004152509.GJ11149@beef (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Am Donnerstag, den 04.10.2012, 11:25 -0400 schrieb Matt Porter: > On Fri, Sep 07, 2012 at 02:43:44PM +0200, Philipp Zabel wrote: > > This driver requests and remaps a memory region as configured in the > > device tree. It serves memory from this region via the genalloc API. > > > > Other drivers can retrieve the genalloc pool from a phandle pointing > > to this drivers' device node in the device tree. > > <snip> > > > + sram->pool = gen_pool_create(PAGE_SHIFT, -1); > > + if (!sram->pool) > > + return -ENOMEM; > > As mentioned in the uio_pruss/genalloc discussion, removing the > hardcoded minimum allocation order will allow this to be used for > a number of other cases. The most notable is moving mach-davinci/ > off of its own genalloc-based SRAM arch driver. Some of the davinci > SoCs have very small SRAMs and need the ability to allocate a smaller > chunk. > > Here's a build-tested patch to add this option: Thank you, > From 6eced8c31eba2f86e72e854cf404d8f58fbeba85 Mon Sep 17 00:00:00 2001 > From: Matt Porter <mporter@ti.com> > Date: Thu, 4 Oct 2012 11:08:02 -0400 > Subject: [PATCH] misc: sram: add support for configurable allocation order > > Adds support for setting the genalloc pool's minimum allocation > order via DT or platform data. The allocation order is optional > for both the DT property and platform data case. If it is not > present then the order defaults to PAGE_SHIFT to preserve the > current behavior. > > Signed-off-by: Matt Porter <mporter@ti.com> Tested-by: Philipp Zabel <p.zabel@pengutronix.de> > --- > Documentation/devicetree/bindings/misc/sram.txt | 12 ++++++++++- > drivers/misc/sram.c | 14 ++++++++++++- > include/linux/platform_data/sram.h | 25 +++++++++++++++++++++++ > 3 files changed, 49 insertions(+), 2 deletions(-) > create mode 100644 include/linux/platform_data/sram.h > > diff --git a/Documentation/devicetree/bindings/misc/sram.txt b/Documentation/devicetree/bindings/misc/sram.txt > index b64136c..b1705ec 100644 > --- a/Documentation/devicetree/bindings/misc/sram.txt > +++ b/Documentation/devicetree/bindings/misc/sram.txt > @@ -8,10 +8,20 @@ Required properties: > > - reg : SRAM iomem address range > > -Example: > +Optional properties: > + > +- alloc-order : Minimum allocation order for the SRAM pool > + > +Examples: > + > +sram: sram@5c000000 { > + compatible = "sram"; > + reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */ > +}; > > sram: sram@5c000000 { > compatible = "sram"; > reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */ > + alloc-order = <9>; /* Minimum 512 byte allocation */ > }; > > diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c > index 7a363f2..3bf8ed3 100644 > --- a/drivers/misc/sram.c > +++ b/drivers/misc/sram.c > @@ -26,6 +26,7 @@ > #include <linux/platform_device.h> > #include <linux/spinlock.h> > #include <linux/genalloc.h> > +#include <linux/platform_data/sram.h> > > struct sram_dev { > struct gen_pool *pool; > @@ -37,6 +38,7 @@ static int __devinit sram_probe(struct platform_device *pdev) > struct sram_dev *sram; > struct resource *res; > unsigned long size; > + u32 alloc_order = PAGE_SHIFT; > int ret; > > res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > @@ -53,7 +55,17 @@ static int __devinit sram_probe(struct platform_device *pdev) > if (!sram) > return -ENOMEM; > > - sram->pool = gen_pool_create(PAGE_SHIFT, -1); > + if (pdev->dev.of_node) > + of_property_read_u32(pdev->dev.of_node, > + "alloc-order", &alloc_order); > + else > + if (pdev->dev.platform_data) { > + struct sram_pdata *pdata = pdev->dev.platform_data; > + if (pdata->alloc_order) > + alloc_order = pdata->alloc_order; > + } > + > + sram->pool = gen_pool_create(alloc_order, -1); > if (!sram->pool) > return -ENOMEM; > > diff --git a/include/linux/platform_data/sram.h b/include/linux/platform_data/sram.h > new file mode 100644 > index 0000000..e17bdaa > --- /dev/null > +++ b/include/linux/platform_data/sram.h > @@ -0,0 +1,25 @@ > +/* > + * include/linux/platform_data/sram.h > + * > + * Platform data for generic sram driver > + * > + * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/ > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License as > + * published by the Free Software Foundation version 2. > + * > + * This program is distributed "as is" WITHOUT ANY WARRANTY of any > + * kind, whether express or implied; without even the implied warranty > + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#ifndef _SRAM_H_ > +#define _SRAM_H_ > + > +struct sram_pdata { > + unsigned alloc_order; /* Optional: driver defaults to PAGE_SHIFT */ > +}; > + > +#endif /* _SRAM_H_ */
diff --git a/Documentation/devicetree/bindings/misc/sram.txt b/Documentation/devicetree/bindings/misc/sram.txt index b64136c..b1705ec 100644 --- a/Documentation/devicetree/bindings/misc/sram.txt +++ b/Documentation/devicetree/bindings/misc/sram.txt @@ -8,10 +8,20 @@ Required properties: - reg : SRAM iomem address range -Example: +Optional properties: + +- alloc-order : Minimum allocation order for the SRAM pool + +Examples: + +sram: sram@5c000000 { + compatible = "sram"; + reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */ +}; sram: sram@5c000000 { compatible = "sram"; reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */ + alloc-order = <9>; /* Minimum 512 byte allocation */ }; diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c index 7a363f2..3bf8ed3 100644 --- a/drivers/misc/sram.c +++ b/drivers/misc/sram.c @@ -26,6 +26,7 @@ #include <linux/platform_device.h> #include <linux/spinlock.h> #include <linux/genalloc.h> +#include <linux/platform_data/sram.h> struct sram_dev { struct gen_pool *pool; @@ -37,6 +38,7 @@ static int __devinit sram_probe(struct platform_device *pdev) struct sram_dev *sram; struct resource *res; unsigned long size; + u32 alloc_order = PAGE_SHIFT; int ret; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); @@ -53,7 +55,17 @@ static int __devinit sram_probe(struct platform_device *pdev) if (!sram) return -ENOMEM; - sram->pool = gen_pool_create(PAGE_SHIFT, -1); + if (pdev->dev.of_node) + of_property_read_u32(pdev->dev.of_node, + "alloc-order", &alloc_order); + else + if (pdev->dev.platform_data) { + struct sram_pdata *pdata = pdev->dev.platform_data; + if (pdata->alloc_order) + alloc_order = pdata->alloc_order; + } + + sram->pool = gen_pool_create(alloc_order, -1); if (!sram->pool) return -ENOMEM; diff --git a/include/linux/platform_data/sram.h b/include/linux/platform_data/sram.h new file mode 100644 index 0000000..e17bdaa --- /dev/null +++ b/include/linux/platform_data/sram.h @@ -0,0 +1,25 @@ +/* + * include/linux/platform_data/sram.h + * + * Platform data for generic sram driver + * + * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/ + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation version 2. + * + * This program is distributed "as is" WITHOUT ANY WARRANTY of any + * kind, whether express or implied; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#ifndef _SRAM_H_ +#define _SRAM_H_ + +struct sram_pdata { + unsigned alloc_order; /* Optional: driver defaults to PAGE_SHIFT */ +}; + +#endif /* _SRAM_H_ */