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.za...@pengutronix.de>
---
Changes since v2:
- Return -EADDRNOTAVAIL if devm_request_and_ioremap fails.
---
drivers/misc/Kconfig | 9 +++++
drivers/misc/Makefile | 1 +
drivers/misc/sram.c | 105 +++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 115 insertions(+)
create mode 100644 drivers/misc/sram.c
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..d6e1230
--- /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 -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),
+};
+
+module_platform_driver(sram_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Philipp Zabel, Pengutronix");
+MODULE_DESCRIPTION("Generic SRAM allocator driver");
--
1.7.10.4
--
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