Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 804 insertions, 0 deletions

diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
new file mode 100644
index 000000000..ed2d8c48e
--- /dev/null
+++ b/drivers/mmc/core/sdio_io.c
@@ -0,0 +1,804 @@
+/*
+ *  linux/drivers/mmc/core/sdio_io.c
+ *
+ *  Copyright 2007-2008 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/export.h>
+#include <linux/mmc/host.h>
+#include <linux/mmc/card.h>
+#include <linux/mmc/sdio.h>
+#include <linux/mmc/sdio_func.h>
+
+#include "sdio_ops.h"
+#include "core.h"
+#include "card.h"
+#include "host.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)
+{
+	if (WARN_ON(!func))
+		return;
+
+	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)
+{
+	if (WARN_ON(!func))
+		return;
+
+	mmc_release_host(func->card->host);
+}
+EXPORT_SYMBOL_GPL(sdio_release_host);
+
+/**
+ *	sdio_enable_func - enables a SDIO function for usage
+ *	@func: SDIO function to enable
+ *
+ *	Powers up and activates a SDIO function so that register
+ *	access is possible.
+ */
+int sdio_enable_func(struct sdio_func *func)
+{
+	int ret;
+	unsigned char reg;
+	unsigned long timeout;
+
+	if (!func)
+		return -EINVAL;
+
+	pr_debug("SDIO: Enabling device %s...\n", sdio_func_id(func));
+
+	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IOEx, 0, &reg);
+	if (ret)
+		goto err;
+
+	reg |= 1 << func->num;
+
+	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IOEx, reg, NULL);
+	if (ret)
+		goto err;
+
+	timeout = jiffies + msecs_to_jiffies(func->enable_timeout);
+
+	while (1) {
+		ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IORx, 0, &reg);
+		if (ret)
+			goto err;
+		if (reg & (1 << func->num))
+			break;
+		ret = -ETIME;
+		if (time_after(jiffies, timeout))
+			goto err;
+	}
+
+	pr_debug("SDIO: Enabled device %s\n", sdio_func_id(func));
+
+	return 0;
+
+err:
+	pr_debug("SDIO: Failed to enable device %s\n", sdio_func_id(func));
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sdio_enable_func);
+
+/**
+ *	sdio_disable_func - disable a SDIO function
+ *	@func: SDIO function to disable
+ *
+ *	Powers down and deactivates a SDIO function. Register access
+ *	to this function will fail until the function is reenabled.
+ */
+int sdio_disable_func(struct sdio_func *func)
+{
+	int ret;
+	unsigned char reg;
+
+	if (!func)
+		return -EINVAL;
+
+	pr_debug("SDIO: Disabling device %s...\n", sdio_func_id(func));
+
+	ret = mmc_io_rw_direct(func->card, 0, 0, SDIO_CCCR_IOEx, 0, &reg);
+	if (ret)
+		goto err;
+
+	reg &= ~(1 << func->num);
+
+	ret = mmc_io_rw_direct(func->card, 1, 0, SDIO_CCCR_IOEx, reg, NULL);
+	if (ret)
+		goto err;
+
+	pr_debug("SDIO: Disabled device %s\n", sdio_func_id(func));
+
+	return 0;
+
+err:
+	pr_debug("SDIO: Failed to disable device %s\n", sdio_func_id(func));
+	return -EIO;
+}
+EXPORT_SYMBOL_GPL(sdio_disable_func);
+
+/**
+ *	sdio_set_block_size - set the block size of an SDIO function
+ *	@func: SDIO function to change
+ *	@blksz: new block size or 0 to use the default.
+ *
+ *	The default block size is the largest supported by both the function
+ *	and the host, with a maximum of 512 to ensure that arbitrarily sized
+ *	data transfer use the optimal (least) number of commands.
+ *
+ *	A driver may call this to override the default block size set by the
+ *	core. This can be used to set a block size greater than the maximum
+ *	that reported by the card; it is the driver's responsibility to ensure
+ *	it uses a value that the card supports.
+ *
+ *	Returns 0 on success, -EINVAL if the host does not support the
+ *	requested block size, or -EIO (etc.) if one of the resultant FBR block
+ *	size register writes failed.
+ *
+ */
+int sdio_set_block_size(struct sdio_func *func, unsigned blksz)
+{
+	int ret;
+
+	if (blksz > func->card->host->max_blk_size)
+		return -EINVAL;
+
+	if (blksz == 0) {
+		blksz = min(func->max_blksize, func->card->host->max_blk_size);
+		blksz = min(blksz, 512u);
+	}
+
+	ret = mmc_io_rw_direct(func->card, 1, 0,
+		SDIO_FBR_BASE(func->num) + SDIO_FBR_BLKSIZE,
+		blksz & 0xff, NULL);
+	if (ret)
+		return ret;
+	ret = mmc_io_rw_direct(func->card, 1, 0,
+		SDIO_FBR_BASE(func->num) + SDIO_FBR_BLKSIZE + 1,
+		(blksz >> 8) & 0xff, NULL);
+	if (ret)
+		return ret;
+	func->cur_blksize = blksz;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sdio_set_block_size);
+
+/*
+ * Calculate the maximum byte mode transfer size
+ */
+static inline unsigned int sdio_max_byte_size(struct sdio_func *func)
+{
+	unsigned mval =	func->card->host->max_blk_size;
+
+	if (mmc_blksz_for_byte_mode(func->card))
+		mval = min(mval, func->cur_blksize);
+	else
+		mval = min(mval, func->max_blksize);
+
+	if (mmc_card_broken_byte_mode_512(func->card))
+		return min(mval, 511u);
+
+	return min(mval, 512u); /* maximum size for byte mode */
+}
+
+/**
+ *	sdio_align_size - pads a transfer size to a more optimal value
+ *	@func: SDIO function
+ *	@sz: original transfer size
+ *
+ *	Pads the original data size with a number of extra bytes in
+ *	order to avoid controller bugs and/or performance hits
+ *	(e.g. some controllers revert to PIO for certain sizes).
+ *
+ *	If possible, it will also adjust the size so that it can be
+ *	handled in just a single request.
+ *
+ *	Returns the improved size, which might be unmodified.
+ */
+unsigned int sdio_align_size(struct sdio_func *func, unsigned int sz)
+{
+	unsigned int orig_sz;
+	unsigned int blk_sz, byte_sz;
+	unsigned chunk_sz;
+
+	orig_sz = sz;
+
+	/*
+	 * Do a first check with the controller, in case it
+	 * wants to increase the size up to a point where it
+	 * might need more than one block.
+	 */
+	sz = mmc_align_data_size(func->card, sz);
+
+	/*
+	 * If we can still do this with just a byte transfer, then
+	 * we're done.
+	 */
+	if (sz <= sdio_max_byte_size(func))
+		return sz;
+
+	if (func->card->cccr.multi_block) {
+		/*
+		 * Check if the transfer is already block aligned
+		 */
+		if ((sz % func->cur_blksize) == 0)
+			return sz;
+
+		/*
+		 * Realign it so that it can be done with one request,
+		 * and recheck if the controller still likes it.
+		 */
+		blk_sz = ((sz + func->cur_blksize - 1) /
+			func->cur_blksize) * func->cur_blksize;
+		blk_sz = mmc_align_data_size(func->card, blk_sz);
+
+		/*
+		 * This value is only good if it is still just
+		 * one request.
+		 */
+		if ((blk_sz % func->cur_blksize) == 0)
+			return blk_sz;
+
+		/*
+		 * We failed to do one request, but at least try to
+		 * pad the remainder properly.
+		 */
+		byte_sz = mmc_align_data_size(func->card,
+				sz % func->cur_blksize);
+		if (byte_sz <= sdio_max_byte_size(func)) {
+			blk_sz = sz / func->cur_blksize;
+			return blk_sz * func->cur_blksize + byte_sz;
+		}
+	} else {
+		/*
+		 * We need multiple requests, so first check that the
+		 * controller can handle the chunk size;
+		 */
+		chunk_sz = mmc_align_data_size(func->card,
+				sdio_max_byte_size(func));
+		if (chunk_sz == sdio_max_byte_size(func)) {
+			/*
+			 * Fix up the size of the remainder (if any)
+			 */
+			byte_sz = orig_sz % chunk_sz;
+			if (byte_sz) {
+				byte_sz = mmc_align_data_size(func->card,
+						byte_sz);
+			}
+
+			return (orig_sz / chunk_sz) * chunk_sz + byte_sz;
+		}
+	}
+
+	/*
+	 * The controller is simply incapable of transferring the size
+	 * we want in decent manner, so just return the original size.
+	 */
+	return orig_sz;
+}
+EXPORT_SYMBOL_GPL(sdio_align_size);
+
+/* Split an arbitrarily sized data transfer into several
+ * IO_RW_EXTENDED commands. */
+static int sdio_io_rw_ext_helper(struct sdio_func *func, int write,
+	unsigned addr, int incr_addr, u8 *buf, unsigned size)
+{
+	unsigned remainder = size;
+	unsigned max_blocks;
+	int ret;
+
+	if (!func || (func->num > 7))
+		return -EINVAL;
+
+	/* Do the bulk of the transfer using block mode (if supported). */
+	if (func->card->cccr.multi_block && (size > sdio_max_byte_size(func))) {
+		/* Blocks per command is limited by host count, host transfer
+		 * size and the maximum for IO_RW_EXTENDED of 511 blocks. */
+		max_blocks = min(func->card->host->max_blk_count, 511u);
+
+		while (remainder >= func->cur_blksize) {
+			unsigned blocks;
+
+			blocks = remainder / func->cur_blksize;
+			if (blocks > max_blocks)
+				blocks = max_blocks;
+			size = blocks * func->cur_blksize;
+
+			ret = mmc_io_rw_extended(func->card, write,
+				func->num, addr, incr_addr, buf,
+				blocks, func->cur_blksize);
+			if (ret)
+				return ret;
+
+			remainder -= size;
+			buf += size;
+			if (incr_addr)
+				addr += size;
+		}
+	}
+
+	/* Write the remainder using byte mode. */
+	while (remainder > 0) {
+		size = min(remainder, sdio_max_byte_size(func));
+
+		/* Indicate byte mode by setting "blocks" = 0 */
+		ret = mmc_io_rw_extended(func->card, write, func->num, addr,
+			 incr_addr, buf, 0, size);
+		if (ret)
+			return ret;
+
+		remainder -= size;
+		buf += size;
+		if (incr_addr)
+			addr += size;
+	}
+	return 0;
+}
+
+/**
+ *	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.
+ */
+u8 sdio_readb(struct sdio_func *func, unsigned int addr, int *err_ret)
+{
+	int ret;
+	u8 val;
+
+	if (!func) {
+		if (err_ret)
+			*err_ret = -EINVAL;
+		return 0xFF;
+	}
+
+	ret = mmc_io_rw_direct(func->card, 0, func->num, addr, 0, &val);
+	if (err_ret)
+		*err_ret = ret;
+	if (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, u8 b, unsigned int addr, int *err_ret)
+{
+	int ret;
+
+	if (!func) {
+		if (err_ret)
+			*err_ret = -EINVAL;
+		return;
+	}
+
+	ret = mmc_io_rw_direct(func->card, 1, func->num, addr, b, NULL);
+	if (err_ret)
+		*err_ret = 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)
+		return 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
+ *	@addr: address to begin reading from
+ *	@count: number of bytes to read
+ *
+ *	Reads from the address space of a given SDIO function. Return
+ *	value indicates if the transfer succeeded or not.
+ */
+int sdio_memcpy_fromio(struct sdio_func *func, void *dst,
+	unsigned int addr, int count)
+{
+	return sdio_io_rw_ext_helper(func, 0, addr, 1, dst, count);
+}
+EXPORT_SYMBOL_GPL(sdio_memcpy_fromio);
+
+/**
+ *	sdio_memcpy_toio - write a chunk of memory to a SDIO function
+ *	@func: SDIO function to access
+ *	@addr: address to start writing to
+ *	@src: buffer that contains the data to write
+ *	@count: number of bytes to write
+ *
+ *	Writes to the address space of a given SDIO function. Return
+ *	value indicates if the transfer succeeded or not.
+ */
+int sdio_memcpy_toio(struct sdio_func *func, unsigned int addr,
+	void *src, int count)
+{
+	return sdio_io_rw_ext_helper(func, 1, addr, 1, src, count);
+}
+EXPORT_SYMBOL_GPL(sdio_memcpy_toio);
+
+/**
+ *	sdio_readsb - read from a FIFO on a SDIO function
+ *	@func: SDIO function to access
+ *	@dst: buffer to store the data
+ *	@addr: address of (single byte) FIFO
+ *	@count: number of bytes to read
+ *
+ *	Reads from the specified FIFO of a given SDIO function. Return
+ *	value indicates if the transfer succeeded or not.
+ */
+int sdio_readsb(struct sdio_func *func, void *dst, unsigned int addr,
+	int count)
+{
+	return sdio_io_rw_ext_helper(func, 0, addr, 0, dst, count);
+}
+EXPORT_SYMBOL_GPL(sdio_readsb);
+
+/**
+ *	sdio_writesb - write to a FIFO of a SDIO function
+ *	@func: SDIO function to access
+ *	@addr: address of (single byte) FIFO
+ *	@src: buffer that contains the data to write
+ *	@count: number of bytes to write
+ *
+ *	Writes to the specified FIFO of a given SDIO function. Return
+ *	value indicates if the transfer succeeded or not.
+ */
+int sdio_writesb(struct sdio_func *func, unsigned int addr, void *src,
+	int count)
+{
+	return sdio_io_rw_ext_helper(func, 1, addr, 0, src, count);
+}
+EXPORT_SYMBOL_GPL(sdio_writesb);
+
+/**
+ *	sdio_readw - read a 16 bit integer from a SDIO function
+ *	@func: SDIO function to access
+ *	@addr: address to read
+ *	@err_ret: optional status value from transfer
+ *
+ *	Reads a 16 bit integer from the address space of a given SDIO
+ *	function. If there is a problem reading the address, 0xffff
+ *	is returned and @err_ret will contain the error code.
+ */
+u16 sdio_readw(struct sdio_func *func, unsigned int addr, int *err_ret)
+{
+	int ret;
+
+	ret = sdio_memcpy_fromio(func, func->tmpbuf, addr, 2);
+	if (err_ret)
+		*err_ret = ret;
+	if (ret)
+		return 0xFFFF;
+
+	return le16_to_cpup((__le16 *)func->tmpbuf);
+}
+EXPORT_SYMBOL_GPL(sdio_readw);
+
+/**
+ *	sdio_writew - write a 16 bit integer to a SDIO function
+ *	@func: SDIO function to access
+ *	@b: integer to write
+ *	@addr: address to write to
+ *	@err_ret: optional status value from transfer
+ *
+ *	Writes a 16 bit integer to the address space of a given SDIO
+ *	function. @err_ret will contain the status of the actual
+ *	transfer.
+ */
+void sdio_writew(struct sdio_func *func, u16 b, unsigned int addr, int *err_ret)
+{
+	int ret;
+
+	*(__le16 *)func->tmpbuf = cpu_to_le16(b);
+
+	ret = sdio_memcpy_toio(func, addr, func->tmpbuf, 2);
+	if (err_ret)
+		*err_ret = ret;
+}
+EXPORT_SYMBOL_GPL(sdio_writew);
+
+/**
+ *	sdio_readl - read a 32 bit integer from a SDIO function
+ *	@func: SDIO function to access
+ *	@addr: address to read
+ *	@err_ret: optional status value from transfer
+ *
+ *	Reads a 32 bit integer from the address space of a given SDIO
+ *	function. If there is a problem reading the address,
+ *	0xffffffff is returned and @err_ret will contain the error
+ *	code.
+ */
+u32 sdio_readl(struct sdio_func *func, unsigned int addr, int *err_ret)
+{
+	int ret;
+
+	ret = sdio_memcpy_fromio(func, func->tmpbuf, addr, 4);
+	if (err_ret)
+		*err_ret = ret;
+	if (ret)
+		return 0xFFFFFFFF;
+
+	return le32_to_cpup((__le32 *)func->tmpbuf);
+}
+EXPORT_SYMBOL_GPL(sdio_readl);
+
+/**
+ *	sdio_writel - write a 32 bit integer to a SDIO function
+ *	@func: SDIO function to access
+ *	@b: integer to write
+ *	@addr: address to write to
+ *	@err_ret: optional status value from transfer
+ *
+ *	Writes a 32 bit integer to the address space of a given SDIO
+ *	function. @err_ret will contain the status of the actual
+ *	transfer.
+ */
+void sdio_writel(struct sdio_func *func, u32 b, unsigned int addr, int *err_ret)
+{
+	int ret;
+
+	*(__le32 *)func->tmpbuf = cpu_to_le32(b);
+
+	ret = sdio_memcpy_toio(func, addr, func->tmpbuf, 4);
+	if (err_ret)
+		*err_ret = ret;
+}
+EXPORT_SYMBOL_GPL(sdio_writel);
+
+/**
+ *	sdio_f0_readb - read a single byte from SDIO function 0
+ *	@func: an SDIO function of the card
+ *	@addr: address to read
+ *	@err_ret: optional status value from transfer
+ *
+ *	Reads a single byte from the address space of SDIO function 0.
+ *	If there is a problem reading the address, 0xff is returned
+ *	and @err_ret will contain the error code.
+ */
+unsigned char sdio_f0_readb(struct sdio_func *func, unsigned int addr,
+	int *err_ret)
+{
+	int ret;
+	unsigned char val;
+
+	if (!func) {
+		if (err_ret)
+			*err_ret = -EINVAL;
+		return 0xFF;
+	}
+
+	ret = mmc_io_rw_direct(func->card, 0, 0, addr, 0, &val);
+	if (err_ret)
+		*err_ret = ret;
+	if (ret)
+		return 0xFF;
+
+	return val;
+}
+EXPORT_SYMBOL_GPL(sdio_f0_readb);
+
+/**
+ *	sdio_f0_writeb - write a single byte to SDIO function 0
+ *	@func: an SDIO function of the card
+ *	@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 SDIO function 0.
+ *	@err_ret will contain the status of the actual transfer.
+ *
+ *	Only writes to the vendor specific CCCR registers (0xF0 -
+ *	0xFF) are permiited; @err_ret will be set to -EINVAL for *
+ *	writes outside this range.
+ */
+void sdio_f0_writeb(struct sdio_func *func, unsigned char b, unsigned int addr,
+	int *err_ret)
+{
+	int ret;
+
+	if (!func) {
+		if (err_ret)
+			*err_ret = -EINVAL;
+		return;
+	}
+
+	if ((addr < 0xF0 || addr > 0xFF) && (!mmc_card_lenient_fn0(func->card))) {
+		if (err_ret)
+			*err_ret = -EINVAL;
+		return;
+	}
+
+	ret = mmc_io_rw_direct(func->card, 1, 0, addr, b, NULL);
+	if (err_ret)
+		*err_ret = ret;
+}
+EXPORT_SYMBOL_GPL(sdio_f0_writeb);
+
+/**
+ *	sdio_get_host_pm_caps - get host power management capabilities
+ *	@func: SDIO function attached to host
+ *
+ *	Returns a capability bitmask corresponding to power management
+ *	features supported by the host controller that the card function
+ *	might rely upon during a system suspend.  The host doesn't need
+ *	to be claimed, nor the function active, for this information to be
+ *	obtained.
+ */
+mmc_pm_flag_t sdio_get_host_pm_caps(struct sdio_func *func)
+{
+	if (!func)
+		return 0;
+
+	return func->card->host->pm_caps;
+}
+EXPORT_SYMBOL_GPL(sdio_get_host_pm_caps);
+
+/**
+ *	sdio_set_host_pm_flags - set wanted host power management capabilities
+ *	@func: SDIO function attached to host
+ *
+ *	Set a capability bitmask corresponding to wanted host controller
+ *	power management features for the upcoming suspend state.
+ *	This must be called, if needed, each time the suspend method of
+ *	the function driver is called, and must contain only bits that
+ *	were returned by sdio_get_host_pm_caps().
+ *	The host doesn't need to be claimed, nor the function active,
+ *	for this information to be set.
+ */
+int sdio_set_host_pm_flags(struct sdio_func *func, mmc_pm_flag_t flags)
+{
+	struct mmc_host *host;
+
+	if (!func)
+		return -EINVAL;
+
+	host = func->card->host;
+
+	if (flags & ~host->pm_caps)
+		return -EINVAL;
+
+	/* function suspend methods are serialized, hence no lock needed */
+	host->pm_flags |= flags;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(sdio_set_host_pm_flags);
+
+/**
+ *	sdio_retune_crc_disable - temporarily disable retuning on CRC errors
+ *	@func: SDIO function attached to host
+ *
+ *	If the SDIO card is known to be in a state where it might produce
+ *	CRC errors on the bus in response to commands (like if we know it is
+ *	transitioning between power states), an SDIO function driver can
+ *	call this function to temporarily disable the SD/MMC core behavior of
+ *	triggering an automatic retuning.
+ *
+ *	This function should be called while the host is claimed and the host
+ *	should remain claimed until sdio_retune_crc_enable() is called.
+ *	Specifically, the expected sequence of calls is:
+ *	- sdio_claim_host()
+ *	- sdio_retune_crc_disable()
+ *	- some number of calls like sdio_writeb() and sdio_readb()
+ *	- sdio_retune_crc_enable()
+ *	- sdio_release_host()
+ */
+void sdio_retune_crc_disable(struct sdio_func *func)
+{
+	func->card->host->retune_crc_disable = true;
+}
+EXPORT_SYMBOL_GPL(sdio_retune_crc_disable);
+
+/**
+ *	sdio_retune_crc_enable - re-enable retuning on CRC errors
+ *	@func: SDIO function attached to host
+ *
+ *	This is the compement to sdio_retune_crc_disable().
+ */
+void sdio_retune_crc_enable(struct sdio_func *func)
+{
+	func->card->host->retune_crc_disable = false;
+}
+EXPORT_SYMBOL_GPL(sdio_retune_crc_enable);
+
+/**
+ *	sdio_retune_hold_now - start deferring retuning requests till release
+ *	@func: SDIO function attached to host
+ *
+ *	This function can be called if it's currently a bad time to do
+ *	a retune of the SDIO card.  Retune requests made during this time
+ *	will be held and we'll actually do the retune sometime after the
+ *	release.
+ *
+ *	This function could be useful if an SDIO card is in a power state
+ *	where it can respond to a small subset of commands that doesn't
+ *	include the retuning command.  Care should be taken when using
+ *	this function since (presumably) the retuning request we might be
+ *	deferring was made for a good reason.
+ *
+ *	This function should be called while the host is claimed.
+ */
+void sdio_retune_hold_now(struct sdio_func *func)
+{
+	mmc_retune_hold_now(func->card->host);
+}
+EXPORT_SYMBOL_GPL(sdio_retune_hold_now);
+
+/**
+ *	sdio_retune_release - signal that it's OK to retune now
+ *	@func: SDIO function attached to host
+ *
+ *	This is the complement to sdio_retune_hold_now().  Calling this
+ *	function won't make a retune happen right away but will allow
+ *	them to be scheduled normally.
+ *
+ *	This function should be called while the host is claimed.
+ */
+void sdio_retune_release(struct sdio_func *func)
+{
+	mmc_retune_release(func->card->host);
+}
+EXPORT_SYMBOL_GPL(sdio_retune_release);