mmc: change .get_ro() callback semantics

Now get_ro() callback must return 0/1 values for its logical states, and
negative errno values in case of error. If particular host instance doesn't
support RO/WP switch, it should return -ENOSYS.

This patch changes some hosts in two ways:

1. Now functions should be smart to not return negative values in
   "RO asserted" case (particularly gpio_ calls could return negative
   values for the outermost GPIOs).

   Also, board code usually passes get_ro() callbacks that directly return
   gpioreg & bit result, so at91_mci, imxmmc, pxamci and mmc_spi's get_ro()
   handlers need take special care when returning platform's values to the
   mmc core.

2. In case of host instance didn't implement get_ro() callback, it should
   really return -ENOSYS and let the mmc core decide what to do about it
   (mmc core thinks the same way as the hosts, so it isn't functional
   change).

Signed-off-by: Anton Vorontsov <avorontsov@ru.mvista.com>
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>

diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
index 7ef3b15c5e3df9dbabb5bfa70923585bf1a6328f..b122eb9ea453d1b705a57865de9d4605125dfb24 100644 (file)
--- a/drivers/mmc/core/sd.c
+++ b/drivers/mmc/core/sd.c
@@ -494,13 +494,13 @@ static int mmc_sd_init_card(struct mmc_host *host, u32 ocr,
         * Check if read-only switch is active.
         */
        if (!oldcard) {
-               if (!host->ops->get_ro) {
+               if (!host->ops->get_ro || host->ops->get_ro(host) < 0) {
                        printk(KERN_WARNING "%s: host does not "
                                "support reading read-only "
                                "switch. assuming write-enable.\n",
                                mmc_hostname(host));
                } else {
-                       if (host->ops->get_ro(host))
+                       if (host->ops->get_ro(host) > 0)
                                mmc_card_set_readonly(card);
                }
        }

diff --git a/drivers/mmc/host/at91_mci.c b/drivers/mmc/host/at91_mci.c
index 8979ad330a4d5e6e154b4e8be4794a0b28765eba..b9d4ed6b29b1655f6e67569645295bb771f5c4a9 100644 (file)
--- a/drivers/mmc/host/at91_mci.c
+++ b/drivers/mmc/host/at91_mci.c
@@ -793,19 +793,15 @@ static irqreturn_t at91_mmc_det_irq(int irq, void *_host)
 
 static int at91_mci_get_ro(struct mmc_host *mmc)
 {
-       int read_only = 0;
        struct at91mci_host *host = mmc_priv(mmc);
 
-       if (host->board->wp_pin) {
-               read_only = gpio_get_value(host->board->wp_pin);
-               printk(KERN_WARNING "%s: card is %s\n", mmc_hostname(mmc),
-                               (read_only ? "read-only" : "read-write") );
-       }
-       else {
-               printk(KERN_WARNING "%s: host does not support reading read-only "
-                               "switch.  Assuming write-enable.\n", mmc_hostname(mmc));
-       }
-       return read_only;
+       if (host->board->wp_pin)
+               return !!gpio_get_value(host->board->wp_pin);
+       /*
+        * Board doesn't support read only detection; let the mmc core
+        * decide what to do.
+        */
+       return -ENOSYS;
 }
 
 static const struct mmc_host_ops at91_mci_ops = {

diff --git a/drivers/mmc/host/imxmmc.c b/drivers/mmc/host/imxmmc.c
index eed211b2ac707dc6bf02af26cdf8c60d443d63d7..5e880c0f13495105105efee78d1eadcebdfa4a29 100644 (file)
--- a/drivers/mmc/host/imxmmc.c
+++ b/drivers/mmc/host/imxmmc.c
@@ -892,9 +892,12 @@ static int imxmci_get_ro(struct mmc_host *mmc)
        struct imxmci_host *host = mmc_priv(mmc);
 
        if (host->pdata && host->pdata->get_ro)
-               return host->pdata->get_ro(mmc_dev(mmc));
-       /* Host doesn't support read only detection so assume writeable */
-       return 0;
+               return !!host->pdata->get_ro(mmc_dev(mmc));
+       /*
+        * Board doesn't support read only detection; let the mmc core
+        * decide what to do.
+        */
+       return -ENOSYS;
 }
 
 

diff --git a/drivers/mmc/host/mmc_spi.c b/drivers/mmc/host/mmc_spi.c
index 547eb857b1b3aac008ca7cb40111bdeead038098..4e82f64a96bc7f3af6ed5a571991c3754369ccd1 100644 (file)
--- a/drivers/mmc/host/mmc_spi.c
+++ b/drivers/mmc/host/mmc_spi.c
@@ -1126,9 +1126,12 @@ static int mmc_spi_get_ro(struct mmc_host *mmc)
        struct mmc_spi_host *host = mmc_priv(mmc);
 
        if (host->pdata && host->pdata->get_ro)
-               return host->pdata->get_ro(mmc->parent);
-       /* board doesn't support read only detection; assume writeable */
-       return 0;
+               return !!host->pdata->get_ro(mmc->parent);
+       /*
+        * Board doesn't support read only detection; let the mmc core
+        * decide what to do.
+        */
+       return -ENOSYS;
 }
 
 static int mmc_spi_get_cd(struct mmc_host *mmc)

diff --git a/drivers/mmc/host/pxamci.c b/drivers/mmc/host/pxamci.c
index d89475d36988228c09e60b54034c288bd81368e6..d39f59738866c02e8712b9d3eb6cc686de808382 100644 (file)
--- a/drivers/mmc/host/pxamci.c
+++ b/drivers/mmc/host/pxamci.c
@@ -374,9 +374,12 @@ static int pxamci_get_ro(struct mmc_host *mmc)
        struct pxamci_host *host = mmc_priv(mmc);
 
        if (host->pdata && host->pdata->get_ro)
-               return host->pdata->get_ro(mmc_dev(mmc));
-       /* Host doesn't support read only detection so assume writeable */
-       return 0;
+               return !!host->pdata->get_ro(mmc_dev(mmc));
+       /*
+        * Board doesn't support read only detection; let the mmc core
+        * decide what to do.
+        */
+       return -ENOSYS;
 }
 
 static void pxamci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)

diff --git a/drivers/mmc/host/wbsd.c b/drivers/mmc/host/wbsd.c
index c303e7f57ab45cf1473fd6c393443aa2e19d994e..67e5a9b80f53831358698d83c9243220cdebc2a1 100644 (file)
--- a/drivers/mmc/host/wbsd.c
+++ b/drivers/mmc/host/wbsd.c
@@ -939,7 +939,7 @@ static int wbsd_get_ro(struct mmc_host *mmc)
 
        spin_unlock_bh(&host->lock);
 
-       return csr & WBSD_WRPT;
+       return !!(csr & WBSD_WRPT);
 }
 
 static const struct mmc_host_ops wbsd_ops = {

diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 6188e19d23310c1fdf59759ac318c8cc04698e58..753b7231b887ff0129d92fe8c5c2056ed29dbcae 100644 (file)
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -58,6 +58,18 @@ struct mmc_host_ops {
         *
         * Also note that these functions might sleep, so don't call them
         * in the atomic contexts!
+        *
+        * Return values for the get_ro callback should be:
+        *   0 for a read/write card
+        *   1 for a read-only card
+        *   -ENOSYS when not supported (equal to NULL callback)
+        *   or a negative errno value when something bad happened
+        *
+        * Return values for the get_ro callback should be:
+        *   0 for a absent card
+        *   1 for a present card
+        *   -ENOSYS when not supported (equal to NULL callback)
+        *   or a negative errno value when something bad happened
         */
        void    (*set_ios)(struct mmc_host *host, struct mmc_ios *ios);
        int     (*get_ro)(struct mmc_host *host);