nvmem: sprd: Optimize the block lock operation

We have some cases that will programme the eFuse block partially multiple
times, so we should allow the block to be programmed again if it was
programmed partially. But we should lock the block if the whole block
was programmed. Thus add a condition to validate if we need lock the
block or not.

Moreover we only enable the auto-check function when locking the block.

Signed-off-by: Freeman Liu <freeman.liu@unisoc.com>
Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20200323150007.7487-3-srinivas.kandagatla@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/nvmem/sprd-efuse.c b/drivers/nvmem/sprd-efuse.c
index 7a189ef523336b6640b86effa4d6782b4dfa41d0..43b3f6ef8c2063d0cfc49a2d1a3c64bb34c3d46f 100644 (file)
--- a/drivers/nvmem/sprd-efuse.c
+++ b/drivers/nvmem/sprd-efuse.c
@@ -217,12 +217,14 @@ static int sprd_efuse_raw_prog(struct sprd_efuse *efuse, u32 blk, bool doub,
         * Enable the auto-check function to validate if the programming is
         * successful.
         */
-       sprd_efuse_set_auto_check(efuse, true);
+       if (lock)
+               sprd_efuse_set_auto_check(efuse, true);
 
        writel(*data, efuse->base + SPRD_EFUSE_MEM(blk));
 
        /* Disable auto-check and data double after programming */
-       sprd_efuse_set_auto_check(efuse, false);
+       if (lock)
+               sprd_efuse_set_auto_check(efuse, false);
        sprd_efuse_set_data_double(efuse, false);
 
        /*
@@ -237,7 +239,7 @@ static int sprd_efuse_raw_prog(struct sprd_efuse *efuse, u32 blk, bool doub,
                writel(SPRD_EFUSE_ERR_CLR_MASK,
                       efuse->base + SPRD_EFUSE_ERR_CLR);
                ret = -EBUSY;
-       } else {
+       } else if (lock) {
                sprd_efuse_set_prog_lock(efuse, lock);
                writel(0, efuse->base + SPRD_EFUSE_MEM(blk));
                sprd_efuse_set_prog_lock(efuse, false);
@@ -322,6 +324,7 @@ unlock:
 static int sprd_efuse_write(void *context, u32 offset, void *val, size_t bytes)
 {
        struct sprd_efuse *efuse = context;
+       bool lock;
        int ret;
 
        ret = sprd_efuse_lock(efuse);
@@ -332,7 +335,20 @@ static int sprd_efuse_write(void *context, u32 offset, void *val, size_t bytes)
        if (ret)
                goto unlock;
 
-       ret = sprd_efuse_raw_prog(efuse, offset, false, false, val);
+       /*
+        * If the writing bytes are equal with the block width, which means the
+        * whole block will be programmed. For this case, we should not allow
+        * this block to be programmed again by locking this block.
+        *
+        * If the block was programmed partially, we should allow this block to
+        * be programmed again.
+        */
+       if (bytes < SPRD_EFUSE_BLOCK_WIDTH)
+               lock = false;
+       else
+               lock = true;
+
+       ret = sprd_efuse_raw_prog(efuse, offset, false, lock, val);
 
        clk_disable_unprepare(efuse->clk);