sdio: add new function for RAW (Read after Write) operation

[pandora-kernel.git] / drivers / mmc / core / sdio_io.c

diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
index ff27c8c..0f687cd 100644 (file)
--- a/drivers/mmc/core/sdio_io.c
+++ b/drivers/mmc/core/sdio_io.c
@@ -405,6 +405,36 @@ 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