mmc: add basic SDIO I/O operations
Add command wrappers that simplify register access from SDIO
function drivers.
Signed-off-by: Pierre Ossman <drzeus@drzeus.cx>
diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
new file mode 100644
index 0000000..4ad06e5
--- /dev/null
+++ b/drivers/mmc/core/sdio_io.c
@@ -0,0 +1,105 @@
+/*
+ * linux/drivers/mmc/core/sdio_io.c
+ *
+ * Copyright 2007 Pierre Ossman
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or (at
+ * your option) any later version.
+ */
+
+#include <linux/mmc/host.h>
+#include <linux/mmc/card.h>
+#include <linux/mmc/sdio_func.h>
+
+#include "sdio_ops.h"
+
+/**
+ * sdio_claim_host - exclusively claim a bus for a certain SDIO function
+ * @func: SDIO function that will be accessed
+ *
+ * Claim a bus for a set of operations. The SDIO function given
+ * is used to figure out which bus is relevant.
+ */
+void sdio_claim_host(struct sdio_func *func)
+{
+ BUG_ON(!func);
+ BUG_ON(!func->card);
+
+ mmc_claim_host(func->card->host);
+}
+EXPORT_SYMBOL_GPL(sdio_claim_host);
+
+/**
+ * sdio_release_host - release a bus for a certain SDIO function
+ * @func: SDIO function that was accessed
+ *
+ * Release a bus, allowing others to claim the bus for their
+ * operations.
+ */
+void sdio_release_host(struct sdio_func *func)
+{
+ BUG_ON(!func);
+ BUG_ON(!func->card);
+
+ mmc_release_host(func->card->host);
+}
+EXPORT_SYMBOL_GPL(sdio_release_host);
+
+/**
+ * sdio_readb - read a single byte from a SDIO function
+ * @func: SDIO function to access
+ * @addr: address to read
+ * @err_ret: optional status value from transfer
+ *
+ * Reads a single byte from the address space of a given SDIO
+ * function. If there is a problem reading the address, 0xff
+ * is returned and @err_ret will contain the error code.
+ */
+unsigned char sdio_readb(struct sdio_func *func, unsigned int addr,
+ int *err_ret)
+{
+ int ret;
+ unsigned char val;
+
+ BUG_ON(!func);
+
+ if (err_ret)
+ *err_ret = 0;
+
+ ret = mmc_io_rw_direct(func->card, 0, func->num, addr, 0, &val);
+ if (ret) {
+ if (err_ret)
+ *err_ret = ret;
+ return 0xFF;
+ }
+
+ return val;
+}
+EXPORT_SYMBOL_GPL(sdio_readb);
+
+/**
+ * sdio_writeb - write a single byte to a SDIO function
+ * @func: SDIO function to access
+ * @b: byte to write
+ * @addr: address to write to
+ * @err_ret: optional status value from transfer
+ *
+ * Writes a single byte to the address space of a given SDIO
+ * function. @err_ret will contain the status of the actual
+ * transfer.
+ */
+void sdio_writeb(struct sdio_func *func, unsigned char b, unsigned int addr,
+ int *err_ret)
+{
+ int ret;
+
+ BUG_ON(!func);
+
+ ret = mmc_io_rw_direct(func->card, 1, func->num, addr, b, NULL);
+ if (err_ret)
+ *err_ret = ret;
+}
+EXPORT_SYMBOL_GPL(sdio_writeb);
+