diff options
| -rw-r--r-- | Documentation/devicetree/bindings/misc/sram.txt | 16 | ||||
| -rw-r--r-- | drivers/misc/Kconfig | 9 | ||||
| -rw-r--r-- | drivers/misc/Makefile | 1 | ||||
| -rw-r--r-- | drivers/misc/sram.c | 121 |
4 files changed, 147 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/misc/sram.txt b/Documentation/devicetree/bindings/misc/sram.txt new file mode 100644 index 000000000000..4d0a00e453a8 --- /dev/null +++ b/Documentation/devicetree/bindings/misc/sram.txt @@ -0,0 +1,16 @@ +Generic on-chip SRAM + +Simple IO memory regions to be managed by the genalloc API. + +Required properties: + +- compatible : mmio-sram + +- reg : SRAM iomem address range + +Example: + +sram: sram@5c000000 { + compatible = "mmio-sram"; + reg = <0x5c000000 0x40000>; /* 256 KiB SRAM at address 0x5c000000 */ +}; diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index e29e7980a359..3659d00efdc5 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig @@ -518,6 +518,15 @@ config LATTICE_ECP3_CONFIG If unsure, say N. +config SRAM + bool "Generic on-chip SRAM driver" + depends on HAS_IOMEM + select GENERIC_ALLOCATOR + help + This driver allows you 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 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 865cbc6a7ae1..c235d5b68311 100644 --- a/drivers/misc/Makefile +++ b/drivers/misc/Makefile @@ -52,3 +52,4 @@ obj-$(CONFIG_ALTERA_STAPL) +=altera-stapl/ obj-$(CONFIG_INTEL_MEI) += mei/ obj-$(CONFIG_VMWARE_VMCI) += vmw_vmci/ obj-$(CONFIG_LATTICE_ECP3_CONFIG) += lattice-ecp3-config.o +obj-$(CONFIG_SRAM) += sram.o diff --git a/drivers/misc/sram.c b/drivers/misc/sram.c new file mode 100644 index 000000000000..437192e43006 --- /dev/null +++ b/drivers/misc/sram.c @@ -0,0 +1,121 @@ +/* + * 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/init.h> +#include <linux/clk.h> +#include <linux/err.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/slab.h> +#include <linux/spinlock.h> +#include <linux/genalloc.h> + +#define SRAM_GRANULARITY 32 + +struct sram_dev { + struct gen_pool *pool; + struct clk *clk; +}; + +static int 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->clk = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(sram->clk)) + sram->clk = NULL; + else + clk_prepare_enable(sram->clk); + + sram->pool = devm_gen_pool_create(&pdev->dev, ilog2(SRAM_GRANULARITY), -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 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); + + if (sram->clk) + clk_disable_unprepare(sram->clk); + + return 0; +} + +#ifdef CONFIG_OF +static struct of_device_id sram_dt_ids[] = { + { .compatible = "mmio-sram" }, + {} +}; +#endif + +static struct platform_driver sram_driver = { + .driver = { + .name = "sram", + .of_match_table = of_match_ptr(sram_dt_ids), + }, + .probe = sram_probe, + .remove = sram_remove, +}; + +static int __init sram_init(void) +{ + return platform_driver_register(&sram_driver); +} + +postcore_initcall(sram_init); |