The phram driver in the MTD subsystem can be used to allow the kernel to use an
MTD or (via mtdblock) a block device in RAM (with the contents loaded by a
bootloader for example). This series has some improvements to make it more
usable by adding device tree support and to significantly improve its
performance by using cached mappings when possible.
Vincent Whitchurch (4):
mtd: core: Check devicetree alias for index
dt-bindings: reserved-memory: Add phram
mtd: phram: Allow probing via reserved-memory
mtd: phram: Allow cached mappings
.../bindings/reserved-memory/phram.yaml | 45 +++++++++++
drivers/mtd/devices/phram.c | 78 +++++++++++++++++--
drivers/mtd/mtdcore.c | 11 ++-
drivers/of/platform.c | 1 +
4 files changed, 127 insertions(+), 8 deletions(-)
create mode 100644 Documentation/devicetree/bindings/reserved-memory/phram.yaml
--
2.34.1
Allow phram to be probed from the devicetree. It expects to be in a
reserved-memory node as documented by the bindings. This allows things
like partitioning to be specified via the devicetree.
Signed-off-by: Vincent Whitchurch <[email protected]>
---
drivers/mtd/devices/phram.c | 67 ++++++++++++++++++++++++++++++++++---
drivers/of/platform.c | 1 +
2 files changed, 64 insertions(+), 4 deletions(-)
diff --git a/drivers/mtd/devices/phram.c b/drivers/mtd/devices/phram.c
index d503821a3e60..6dfe9401a3c5 100644
--- a/drivers/mtd/devices/phram.c
+++ b/drivers/mtd/devices/phram.c
@@ -27,6 +27,9 @@
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <asm/div64.h>
+#include <linux/platform_device.h>
+#include <linux/of_address.h>
+#include <linux/of.h>
struct phram_mtd_list {
struct mtd_info mtd;
@@ -89,8 +92,10 @@ static void unregister_devices(void)
}
}
-static int register_device(char *name, phys_addr_t start, size_t len, uint32_t erasesize)
+static int register_device(struct platform_device *pdev, const char *name,
+ phys_addr_t start, size_t len, uint32_t erasesize)
{
+ struct device_node *np = pdev ? pdev->dev.of_node : NULL;
struct phram_mtd_list *new;
int ret = -ENOMEM;
@@ -119,13 +124,19 @@ static int register_device(char *name, phys_addr_t start, size_t len, uint32_t e
new->mtd.erasesize = erasesize;
new->mtd.writesize = 1;
+ mtd_set_of_node(&new->mtd, np);
+
ret = -EAGAIN;
if (mtd_device_register(&new->mtd, NULL, 0)) {
pr_err("Failed to register new device\n");
goto out2;
}
- list_add_tail(&new->list, &phram_list);
+ if (pdev)
+ platform_set_drvdata(pdev, new);
+ else
+ list_add_tail(&new->list, &phram_list);
+
return 0;
out2:
@@ -278,7 +289,7 @@ static int phram_setup(const char *val)
goto error;
}
- ret = register_device(name, start, len, (uint32_t)erasesize);
+ ret = register_device(NULL, name, start, len, (uint32_t)erasesize);
if (ret)
goto error;
@@ -325,10 +336,54 @@ static int phram_param_call(const char *val, const struct kernel_param *kp)
module_param_call(phram, phram_param_call, NULL, NULL, 0200);
MODULE_PARM_DESC(phram, "Memory region to map. \"phram=<name>,<start>,<length>[,<erasesize>]\"");
+#ifdef CONFIG_OF
+static const struct of_device_id phram_of_match[] = {
+ { .compatible = "phram" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, phram_of_match)
+#endif
+
+static int phram_probe(struct platform_device *pdev)
+{
+ struct resource *res;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res)
+ return -ENOMEM;
+
+ /* mtd_set_of_node() reads name from "label" */
+ return register_device(pdev, NULL, res->start, resource_size(res),
+ PAGE_SIZE);
+}
+
+static int phram_remove(struct platform_device *pdev)
+{
+ struct phram_mtd_list *phram = platform_get_drvdata(pdev);
+
+ mtd_device_unregister(&phram->mtd);
+ iounmap(phram->mtd.priv);
+ kfree(phram);
+
+ return 0;
+}
+
+static struct platform_driver phram_driver = {
+ .probe = phram_probe,
+ .remove = phram_remove,
+ .driver = {
+ .name = "phram",
+ .of_match_table = of_match_ptr(phram_of_match),
+ },
+};
static int __init init_phram(void)
{
- int ret = 0;
+ int ret;
+
+ ret = platform_driver_register(&phram_driver);
+ if (ret)
+ return ret;
#ifndef MODULE
if (phram_paramline[0])
@@ -336,12 +391,16 @@ static int __init init_phram(void)
phram_init_called = 1;
#endif
+ if (ret)
+ platform_driver_unregister(&phram_driver);
+
return ret;
}
static void __exit cleanup_phram(void)
{
unregister_devices();
+ platform_driver_unregister(&phram_driver);
}
module_init(init_phram);
diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index a16b74f32aa9..55d62b82c650 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -509,6 +509,7 @@ EXPORT_SYMBOL_GPL(of_platform_default_populate);
#ifndef CONFIG_PPC
static const struct of_device_id reserved_mem_matches[] = {
+ { .compatible = "phram" },
{ .compatible = "qcom,rmtfs-mem" },
{ .compatible = "qcom,cmd-db" },
{ .compatible = "qcom,smem" },
--
2.34.1