Re: [PATCH v2 6/9] misc: Generic on-chip SRAM allocation driver
From: Shawn Guo <hidden>
Date: 2012-09-03 02:20:03
Also in:
linux-arm-kernel, lkml
On Fri, Aug 31, 2012 at 11:27:01AM +0200, Philipp Zabel wrote:
quoted hunk ↗ jump to hunk
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> --- drivers/misc/Kconfig | 8 ++++ drivers/misc/Makefile | 1 + drivers/misc/sram.c | 105 +++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 114 insertions(+) create mode 100644 drivers/misc/sram.cdiff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig index 98a442d..8a55284 100644 --- a/drivers/misc/Kconfig +++ b/drivers/misc/Kconfig@@ -509,6 +509,14 @@ 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\n"
Remove the "\n". And "depends on HAS_IOMEM"?
quoted hunk ↗ jump to hunk
+ 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.odiff --git a/drivers/misc/sram.c b/drivers/misc/sram.c new file mode 100644 index 0000000..c5cf67e --- /dev/null +++ b/drivers/misc/sram.c@@ -0,0 +1,105 @@ +/* + * 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/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 -ENOMEM;
The kerneldoc of devm_request_and_ioremap suggests -EADDRNOTAVAIL. Regards, Shawn
+
+ 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),
+};
+
+module_platform_driver(sram_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Philipp Zabel, Pengutronix");
+MODULE_DESCRIPTION("Generic SRAM allocator driver");
--
1.7.10.4