mtd: phram: Allow probing via reserved-memory

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 <vincent.whitchurch@axis.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20220412135302.1682890-4-vincent.whitchurch@axis.com

diff --git a/drivers/mtd/devices/phram.c b/drivers/mtd/devices/phram.c
index d503821..506e9ed 100644 (file)
--- 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 a16b74f..55d62b8 100644 (file)
--- 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" },