mtd: spear_smi: handle return value of timeouts properly

Handle timouts in general and return value of
'wait_event_interruptible_timeout' in particular, to capture all
conditions.

'wait_event_interruptible_timeout' returns either of the following three
values :-
   * 0               - time out occurred.
   * negative
      * -ERESTARTSYS - return because of a signal
      * other        - for a real error
   * positive        - time remaining

Fix particularly 'ERESTARTSYS' condition which is not properly handled
by the smi driver at a couple of places leading to an erroneous
situation.

Signed-off-by: Antonio BORNEO <antonio.borneo@st.com>
Signed-off-by: Shiraz Hashim <shiraz.hashim@st.com>
Signed-off-by: Vipin Kumar <vipin.kumar@st.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

1 files changed, 13 insertions, 10 deletions

diff --git a/drivers/mtd/devices/spear_smi.c b/drivers/mtd/devices/spear_smi.c
index aec941e74e67..b85f183d24c0 100644
--- a/drivers/mtd/devices/spear_smi.c
+++ b/drivers/mtd/devices/spear_smi.c
@@ -241,8 +241,8 @@ static int spear_smi_read_sr(struct spear_smi *dev, u32 bank)
         /* copy dev->status (lower 16 bits) in order to release lock */
         if (ret > 0)
                 ret = dev->status & 0xffff;
-        else
-                ret = -EIO;
+        else if (ret == 0)
+                ret = -ETIMEDOUT;
 
         /* restore the ctrl regs state */
         writel(ctrlreg1, dev->io_base + SMI_CR1);
@@ -270,16 +270,19 @@ static int spear_smi_wait_till_ready(struct spear_smi *dev, u32 bank,
         finish = jiffies + timeout;
         do {
                 status = spear_smi_read_sr(dev, bank);
-                if (status < 0)
-                        continue; /* try till timeout */
-                else if (!(status & SR_WIP))
+                if (status < 0) {
+                        if (status == -ETIMEDOUT)
+                                continue; /* try till finish */
+                        return status;
+                } else if (!(status & SR_WIP)) {
                         return 0;
+                }
 
                 cond_resched();
         } while (!time_after_eq(jiffies, finish));
 
         dev_err(&dev->pdev->dev, "smi controller is busy, timeout\n");
-        return status;
+        return -EBUSY;
 }
 
 /**
@@ -395,11 +398,11 @@ static int spear_smi_write_enable(struct spear_smi *dev, u32 bank)
         writel(ctrlreg1, dev->io_base + SMI_CR1);
         writel(0, dev->io_base + SMI_CR2);
 
-        if (ret <= 0) {
+        if (ret == 0) {
                 ret = -EIO;
                 dev_err(&dev->pdev->dev,
                         "smi controller failed on write enable\n");
-        } else {
+        } else if (ret > 0) {
                 /* check whether write mode status is set for required bank */
                 if (dev->status & (1 << (bank + WM_SHIFT)))
                         ret = 0;
@@ -466,10 +469,10 @@ static int spear_smi_erase_sector(struct spear_smi *dev,
         ret = wait_event_interruptible_timeout(dev->cmd_complete,
                         dev->status & TFF, SMI_CMD_TIMEOUT);
 
-        if (ret <= 0) {
+        if (ret == 0) {
                 ret = -EIO;
                 dev_err(&dev->pdev->dev, "sector erase failed\n");
-        } else
+        } else if (ret > 0)
                 ret = 0; /* success */
 
         /* restore ctrl regs */