Messages in this thread Patch in this message | | | From | Philipp Zabel <> | Subject | [PATCH v4 2/6] misc: Generic on-chip SRAM allocation driver | Date | Fri, 7 Sep 2012 14:43:44 +0200 |
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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.
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de> Reviewed-by: Shawn Guo <shawn.guo@linaro.org> --- Changes since v3: - Added devicetree binding documentation - Register platform driver with postcore_initcall --- Documentation/devicetree/bindings/misc/sram.txt | 17 ++++ drivers/misc/Kconfig | 9 ++ drivers/misc/Makefile | 1 + drivers/misc/sram.c | 111 +++++++++++++++++++++++ 4 files changed, 138 insertions(+) create mode 100644 Documentation/devicetree/bindings/misc/sram.txt create mode 100644 drivers/misc/sram.c
diff --git a/Documentation/devicetree/bindings/misc/sram.txt b/Documentation/devicetree/bindings/misc/sram.txt new file mode 100644 index 0000000..8bb26fc --- /dev/null +++ b/Documentation/devicetree/bindings/misc/sram.txt @@ -0,0 +1,17 @@ +Generic on-chip SRAM + +Simple IO memory regions to be managed by the genalloc API. + +Required properties: + +- compatible : sram + +- reg : SRAM iomem address range + +Example: + +sram: sram@5c000000 { + compatible = "sram"; + reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */ +}; + diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 98a442d..9a3395f 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -509,6 +509,15 @@ config USB_SWITCH_FSA9480 stereo and mono audio, video, microphone and UART data to use a common connector port. +config SRAM + bool "Generic on-chip SRAM driver" + depends on HAS_IOMEM + select GENERIC_ALLOCATOR + help + This driver allows to declare a memory region to be managed + by the genalloc API. It is supposed to be used for small + on-chip SRAM areas found on many ARM SoCs. + source "drivers/misc/c2port/Kconfig" source "drivers/misc/eeprom/Kconfig" source "drivers/misc/cb710/Kconfig" diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile index b88df7a..ccc759a 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -50,3 +50,4 @@ obj-y += carma/ obj-$(CONFIG_USB_SWITCH_FSA9480) += fsa9480.o obj-$(CONFIG_ALTERA_STAPL) +=altera-stapl/ obj-$(CONFIG_INTEL_MEI) += mei/ +obj-$(CONFIG_SRAM) += sram.o diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c new file mode 100644 index 0000000..7a363f2 --- /dev/null +++ b/drivers/misc/sram.c @@ -0,0 +1,111 @@ +/* + * Generic on-chip SRAM allocation driver + * + * Copyright (C) 2012 Philipp Zabel, Pengutronix + * + * 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; either version 2 + * of the License, or (at your option) any later version. + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, + * MA 02110-1301, USA. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/init.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/spinlock.h> +#include <linux/genalloc.h> + +struct sram_dev { + struct gen_pool *pool; +}; + +static int __devinit sram_probe(struct platform_device *pdev) +{ + void __iomem *virt_base; + struct sram_dev *sram; + struct resource *res; + unsigned long size; + int ret; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + if (!res) + return -EINVAL; + + size = resource_size(res); + + virt_base = devm_request_and_ioremap(&pdev->dev, res); + if (!virt_base) + return -EADDRNOTAVAIL; + + sram = devm_kzalloc(&pdev->dev, sizeof(*sram), GFP_KERNEL); + if (!sram) + return -ENOMEM; + + sram->pool = gen_pool_create(PAGE_SHIFT, -1); + if (!sram->pool) + return -ENOMEM; + + ret = gen_pool_add_virt(sram->pool, (unsigned long)virt_base, + res->start, size, -1); + if (ret < 0) { + gen_pool_destroy(sram->pool); + return ret; + } + + platform_set_drvdata(pdev, sram); + + dev_dbg(&pdev->dev, "SRAM pool: %ld KiB @ 0x%p\n", size / 1024, virt_base); + + return 0; +} + +static int __devexit sram_remove(struct platform_device *pdev) +{ + struct sram_dev *sram = platform_get_drvdata(pdev); + + if (gen_pool_avail(sram->pool) < gen_pool_size(sram->pool)) + dev_dbg(&pdev->dev, "removed while SRAM allocated\n"); + + gen_pool_destroy(sram->pool); + + return 0; +} + +#ifdef CONFIG_OF +static struct of_device_id sram_dt_ids[] = { + { .compatible = "sram" }, + { /* sentinel */ } +}; +#endif + +static struct platform_driver sram_driver = { + .driver = { + .name = "sram", + .of_match_table = of_match_ptr(sram_dt_ids), + }, + .probe = sram_probe, + .remove = __devexit_p(sram_remove), +}; + +int __init sram_init(void) +{ + return platform_driver_register(&sram_driver); +} + +postcore_initcall(sram_init); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Philipp Zabel, Pengutronix"); +MODULE_DESCRIPTION("Generic SRAM allocator driver"); -- 1.7.10.4
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