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>

3 files changed, 119 insertions, 1 deletions

diff --git a/drivers/mmc/core/Makefile b/drivers/mmc/core/Makefile
index 71ab3d1e1eb..bf7a0024803 100644
--- a/drivers/mmc/core/Makefile
+++ b/drivers/mmc/core/Makefile
@@ -9,5 +9,6 @@ endif
 obj-$(CONFIG_MMC)		+= mmc_core.o
 mmc_core-y			:= core.o sysfs.o bus.o host.o \
 				   mmc.o mmc_ops.o sd.o sd_ops.o \
-				   sdio.o sdio_ops.o sdio_bus.o
+				   sdio.o sdio_ops.o sdio_bus.o \
+				   sdio_io.o
 
diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
new file mode 100644
index 00000000000..4ad06e57563
--- /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);
+
diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h
index 13a1a9ca4b6..5c56df19628 100644
--- a/include/linux/mmc/sdio_func.h
+++ b/include/linux/mmc/sdio_func.h
@@ -49,5 +49,17 @@ struct sdio_driver {
 extern int sdio_register_driver(struct sdio_driver *);
 extern void sdio_unregister_driver(struct sdio_driver *);
 
+/*
+ * SDIO I/O operations
+ */
+extern void sdio_claim_host(struct sdio_func *func);
+extern void sdio_release_host(struct sdio_func *func);
+
+extern unsigned char sdio_readb(struct sdio_func *func,
+	unsigned int addr, int *err_ret);
+
+extern void sdio_writeb(struct sdio_func *func, unsigned char b,
+	unsigned int addr, int *err_ret);
+
 #endif