mmc: block: Support the fixed index for mmcblk with aliases nodes

Now, index of mmcblk is allocated in accordance with probing time.
If want to use the mmcblk1 for some device, it can use alias.

aliases {
	mmc0 = &mmc0;	/* mmcblk0 for eMMC */
	mmc1 = &mmc2;	/* mmcblk1 for SD */
	mmc2 = &mmc1;	/* mmcblk2 for SDIO*/
};

If there are no corresponding values, it might be allocated with
existing scheme.

Signed-off-by: Jaehoon Chung <jh80.chung@samsung.com>
[sw0312.kim: port to v4.14
 - apply to host index instead of name_idx because host index is used in this version
]
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Change-Id: I44673d62e546ea0aeedd9cac314dbfd31fdcce66

diff --git a/Documentation/devicetree/bindings/mmc/mmc.txt b/Documentation/devicetree/bindings/mmc/mmc.txt
index b32ade6..a6f51dd 100644 (file)
--- a/Documentation/devicetree/bindings/mmc/mmc.txt
+++ b/Documentation/devicetree/bindings/mmc/mmc.txt
@@ -76,6 +76,11 @@ Optional SDIO properties:
 - wakeup-source: Enables wake up of host system on SDIO IRQ assertion
                 (Legacy property supported: "enable-sdio-wakeup")
 
+Aliases (Optional):
+- If you want to use the fixed index for block device like mmcblkX, should be
+represented in the aliases node using following format "mmc(X)".
+(X is an unique number for the alias.)
+
 MMC power
 ---------
 
@@ -162,3 +167,10 @@ mmc3: mmc@01c12000 {
                interrupt-names = "host-wake";
        };
 };
+
+Example with aliases nodes:
+
+aliases {
+       mmc0 = &mmc0;   /* Fixed to mmcblk0 for &mmc0 */
+       mmc1 = &mmc2;   /* Fixed to mmcblk1 for &mmc2 */
+};

diff --git a/drivers/mmc/core/host.c b/drivers/mmc/core/host.c
index ad88deb..390e676 100644 (file)
--- a/drivers/mmc/core/host.c
+++ b/drivers/mmc/core/host.c
@@ -349,6 +349,7 @@ EXPORT_SYMBOL(mmc_of_parse);
 struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
 {
        int err;
+       int idx = 0;
        struct mmc_host *host;
 
        host = kzalloc(sizeof(struct mmc_host) + extra, GFP_KERNEL);
@@ -358,7 +359,10 @@ struct mmc_host *mmc_alloc_host(int extra, struct device *dev)
        /* scanning will be enabled when we're ready */
        host->rescan_disable = 1;
 
-       err = ida_simple_get(&mmc_host_ida, 0, 0, GFP_KERNEL);
+       if (dev->of_node)
+               idx = of_alias_get_id(dev->of_node, "mmc");
+
+       err = ida_simple_get(&mmc_host_ida, (idx < 0) ? 0 : idx, 0, GFP_KERNEL);
        if (err < 0) {
                kfree(host);
                return NULL;