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-rw-r--r--drivers/mmc/core/sdio_io.c30
-rw-r--r--include/linux/mmc/sdio_func.h3
2 files changed, 33 insertions, 0 deletions
diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
index ff27c8c71355..0f687cdeb064 100644
--- a/drivers/mmc/core/sdio_io.c
+++ b/drivers/mmc/core/sdio_io.c
@@ -406,6 +406,36 @@ void sdio_writeb(struct sdio_func *func, u8 b, unsigned int addr, int *err_ret)
EXPORT_SYMBOL_GPL(sdio_writeb);
/**
+ * sdio_writeb_readb - write and read a byte from SDIO function
+ * @func: SDIO function to access
+ * @write_byte: byte to write
+ * @addr: address to write to
+ * @err_ret: optional status value from transfer
+ *
+ * Performs a RAW (Read after Write) operation as defined by SDIO spec -
+ * single byte is written to address space of a given SDIO function and
+ * response is read back from the same address, both using single request.
+ * If there is a problem with the operation, 0xff is returned and
+ * @err_ret will contain the error code.
+ */
+u8 sdio_writeb_readb(struct sdio_func *func, u8 write_byte,
+ unsigned int addr, int *err_ret)
+{
+ int ret;
+ u8 val;
+
+ ret = mmc_io_rw_direct(func->card, 1, func->num, addr,
+ write_byte, &val);
+ if (err_ret)
+ *err_ret = ret;
+ if (ret)
+ val = 0xff;
+
+ return val;
+}
+EXPORT_SYMBOL_GPL(sdio_writeb_readb);
+
+/**
* sdio_memcpy_fromio - read a chunk of memory from a SDIO function
* @func: SDIO function to access
* @dst: buffer to store the data
diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h
index c6c0cceba5fe..31baaf82f458 100644
--- a/include/linux/mmc/sdio_func.h
+++ b/include/linux/mmc/sdio_func.h
@@ -145,6 +145,9 @@ extern void sdio_writew(struct sdio_func *func, u16 b,
extern void sdio_writel(struct sdio_func *func, u32 b,
unsigned int addr, int *err_ret);
+extern u8 sdio_writeb_readb(struct sdio_func *func, u8 write_byte,
+ unsigned int addr, int *err_ret);
+
extern int sdio_memcpy_toio(struct sdio_func *func, unsigned int addr,
void *src, int count);
extern int sdio_writesb(struct sdio_func *func, unsigned int addr,