Date: Tue, 7 Aug 2007 22:17:19 +0200
From: Pierre Ossman <drzeus-list@drzeus.cx>
To: David Vrabel <david.vrabel@csr.com>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [patch 3/4] sdio: extend sdio_readsb() and friends to handle
 any length of buffer
Message-ID: <20070807221719.7c89e5b6@poseidon.drzeus.cx>
In-Reply-To: <46B86BB0.4000100@csr.com>
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	<20070806220145.66b97559@poseidon.drzeus.cx>
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Here's my proposed compromise.

If a driver uses sdio_force_block_size() extensively, it will be like
your original version with sdio_set_block_size(). If it doesn't,
however, then that is a way to indicate that the driver has no specific
requirements (meaning we are free to change things in the future).

You'll also notice that calling sdio_force_block_size() is free. The
actual change comes when it is first used, meaning that drivers don't
have to be as careful when calling it.

The reset of custom/forced block size is moved to the probe function as
you suggested.

diff --git a/drivers/mmc/core/sdio_bus.c b/drivers/mmc/core/sdio_bus.c
index ca1d4b2..6ead36a 100644
--- a/drivers/mmc/core/sdio_bus.c
+++ b/drivers/mmc/core/sdio_bus.c
@@ -133,6 +133,8 @@ static int sdio_bus_probe(struct device *dev)
 	if (!id)
 		return -ENODEV;
 
+	func->forced_blksz = 0;
+
 	return drv->probe(func, id);
 }
 
diff --git a/drivers/mmc/core/sdio_cis.c b/drivers/mmc/core/sdio_cis.c
index fffbc5a..20fdd1d 100644
--- a/drivers/mmc/core/sdio_cis.c
+++ b/drivers/mmc/core/sdio_cis.c
@@ -145,9 +145,9 @@ static int cistpl_funce_func(struct sdio_func *func,
 	printk(KERN_DEBUG "%s: TPLFE_CSA_PROPERTY = 0x%02x\n",
 	       sdio_func_id(func), val);
 	/* TPLFE_MAX_BLK_SIZE */
-	func->blksize = buf[12] | (buf[13] << 8);
+	func->max_blksz = buf[12] | (buf[13] << 8);
 	printk(KERN_DEBUG "%s: TPLFE_MAX_BLK_SIZE = %u\n",
-	       sdio_func_id(func), (unsigned)func->blksize);
+	       sdio_func_id(func), (unsigned)func->max_blksz);
 	/* TPLFE_OCR */
 	val = buf[14] | (buf[15] << 8) | (buf[16] << 16) | (buf[17] << 24);
 	printk(KERN_DEBUG "%s: TPLFE_OCR = 0x%08x\n",
diff --git a/drivers/mmc/core/sdio_io.c b/drivers/mmc/core/sdio_io.c
index 7f08ba5..46ada64 100644
--- a/drivers/mmc/core/sdio_io.c
+++ b/drivers/mmc/core/sdio_io.c
@@ -202,6 +202,115 @@ void sdio_writeb(struct sdio_func *func, unsigned char b, unsigned int addr,
 
 EXPORT_SYMBOL_GPL(sdio_writeb);
 
+/*
+ * Internal function. Sets the block size of the card.
+ */
+static int sdio_set_block_size(struct sdio_func *func, unsigned short blksz)
+{
+	int ret;
+
+	if (blksz == func->cur_blksz)
+		return 0;
+
+	/*
+	 * We start by clearing the current block size as a failure
+	 * will leave the size on the card in an unknown state.
+	 */
+	func->cur_blksz = 0;
+
+	ret = mmc_io_rw_direct(func->card, 1, 0,
+			func->num * 0x100 + SDIO_FBR_BLKSIZE,
+			blksz & 0xff, NULL);
+	if (ret)
+		return ret;
+
+	ret = mmc_io_rw_direct(func->card, 1, 0,
+			func->num * 0x100 + SDIO_FBR_BLKSIZE + 1,
+			(blksz >> 8) & 0xff, NULL);
+	if (ret)
+		return ret;
+
+	func->cur_blksz = blksz;
+
+	return 0;
+}
+
+/*
+ * Internal function. Splits 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;
+	int ret;
+	unsigned short blksz;
+	struct mmc_host *host = func->card->host;
+
+	if (func->forced_blksz)
+		blksz = func->forced_blksz;
+	else {
+		blksz = func->max_blksz;
+		if (blksz > host->max_blk_size)
+			blksz = host->max_blk_size;
+		if (blksz > 512)
+			blksz = 512;
+	}
+
+	WARN_ON(blksz > 512);
+
+	ret = sdio_set_block_size(func, blksz);
+	if (ret)
+		return ret;
+
+	while (remainder >= blksz) {
+		unsigned blocks;
+
+		blocks = remainder / blksz;
+
+		if (blocks > 511)
+			blocks = 511;
+		if (blocks > host->max_blk_count)
+			blocks = host->max_blk_count;
+		if (blocks * blksz > host->max_req_size)
+			blocks = host->max_req_size / blksz;
+		if (blocks * blksz > host->max_seg_size)
+			blocks = host->max_seg_size / blksz;
+
+		size = blocks * blksz;
+
+		ret = mmc_io_rw_extended(func->card, write, func->num,
+				addr, incr_addr, buf, blocks, blksz);
+		if (ret)
+			return ret;
+
+		remainder -= size;
+		buf += size;
+		if (incr_addr)
+			addr += size;
+	}
+
+	/*
+	 * Because the block size is smaller than both the card
+	 * maximum size and 512, then we know we can fit the remainder
+	 * into a byte transfer.
+	 */
+	if (remainder) {
+		/*
+		 * We don't check host requirements as a block of 512
+		 * bytes is the bare minimum support a host must
+		 * provide.
+		 */
+
+		ret = mmc_io_rw_extended(func->card, write, func->num,
+				addr, incr_addr, buf, 1, remainder);
+		if (ret)
+			return ret;
+	}
+
+	return 0;
+}
+
 /**
  *	sdio_memcpy_fromio - read a chunk of memory from a SDIO function
  *	@func: SDIO function to access
@@ -209,14 +318,13 @@ EXPORT_SYMBOL_GPL(sdio_writeb);
  *	@addr: address to begin reading from
  *	@count: number of bytes to read
  *
- *	Reads up to 512 bytes from the address space of a given SDIO
- *	function. Return value indicates if the transfer succeeded or
- *	not.
+ *	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 mmc_io_rw_extended(func->card, 0, func->num, addr, 0, dst,
+	return sdio_io_rw_ext_helper(func, 0, addr, 1, dst,
 		count);
 }
 
@@ -229,14 +337,13 @@ EXPORT_SYMBOL_GPL(sdio_memcpy_fromio);
  *	@src: buffer that contains the data to write
  *	@count: number of bytes to write
  *
- *	Writes up to 512 bytes to the address space of a given SDIO
- *	function. Return value indicates if the transfer succeeded or
- *	not.
+ *	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 mmc_io_rw_extended(func->card, 1, func->num, addr, 0, src,
+	return sdio_io_rw_ext_helper(func, 1, addr, 1, src,
 		count);
 }
 
@@ -247,14 +354,13 @@ int sdio_memcpy_toio(struct sdio_func *func, unsigned int addr,
  *	@addr: address of (single byte) FIFO
  *	@count: number of bytes to read
  *
- *	Reads up to 512 bytes from the specified FIFO of a given SDIO
- *	function. Return value indicates if the transfer succeeded or
- *	not.
+ *	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 mmc_io_rw_extended(func->card, 0, func->num, addr, 1, dst,
+	return sdio_io_rw_ext_helper(func, 0, addr, 0, dst,
 		count);
 }
 
@@ -267,14 +373,13 @@ EXPORT_SYMBOL_GPL(sdio_readsb);
  *	@src: buffer that contains the data to write
  *	@count: number of bytes to write
  *
- *	Writes up to 512 bytes to the specified FIFO of a given SDIO
- *	function. Return value indicates if the transfer succeeded or
- *	not.
+ *	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 mmc_io_rw_extended(func->card, 1, func->num, addr, 1, src,
+	return sdio_io_rw_ext_helper(func, 1, addr, 0, src,
 		count);
 }
 
@@ -393,3 +498,30 @@ void sdio_writel(struct sdio_func *func, unsigned long b, unsigned int addr,
 
 EXPORT_SYMBOL_GPL(sdio_writel);
 
+/**
+ *	sdio_force_block_size - lock a certain block size
+ *	@func: SDIO function to set block size for
+ *	@size: block size in bytes, or 0 to remove any lock
+ *
+ *	Locks the used block size for all multi-block sdio functions
+ *	in order to satisfy transactions with precise requirements.
+ *	This lock can be removed by specifying 0 (zero) as the block
+ *	size. Returns failure if the selected block size isn't
+ *	supported.
+ */
+int sdio_force_block_size(struct sdio_func *func, unsigned short size)
+{
+	if (size > func->max_blksz)
+		return -EINVAL;
+	if (size > func->card->host->max_blk_size)
+		return -EINVAL;
+	if (size > 512)
+		return -EINVAL;
+
+	func->forced_blksz = size;
+
+	return 0;
+}
+
+EXPORT_SYMBOL_GPL(sdio_force_block_size);
+
diff --git a/drivers/mmc/core/sdio_ops.c b/drivers/mmc/core/sdio_ops.c
index 277870c..b5bbcfc 100644
--- a/drivers/mmc/core/sdio_ops.c
+++ b/drivers/mmc/core/sdio_ops.c
@@ -88,7 +88,7 @@ int mmc_io_rw_direct(struct mmc_card *card, int write, unsigned fn,
 }
 
 int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn,
-	unsigned addr, int bang, u8 *buf, unsigned size)
+	unsigned addr, int incr_addr, u8 *buf, unsigned blocks, unsigned blksz)
 {
 	struct mmc_request mrq;
 	struct mmc_command cmd;
@@ -97,7 +97,7 @@ int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn,
 
 	BUG_ON(!card);
 	BUG_ON(fn > 7);
-	BUG_ON(size > 512);
+	BUG_ON(blocks > 511);
 
 	memset(&mrq, 0, sizeof(struct mmc_request));
 	memset(&cmd, 0, sizeof(struct mmc_command));
@@ -107,20 +107,27 @@ int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn,
 	mrq.data = &data;
 
 	cmd.opcode = SD_IO_RW_EXTENDED;
+
 	cmd.arg = write ? 0x80000000 : 0x00000000;
 	cmd.arg |= fn << 28;
-	cmd.arg |= bang ? 0x00000000 : 0x04000000;
+	cmd.arg |= incr_addr ? 0x04000000 : 0x00000000;
 	cmd.arg |= addr << 9;
-	cmd.arg |= (size == 512) ? 0 : size;
+
+	if ((blocks > 1) || (blksz > 512)) {
+		cmd.arg |= 0x08000000;
+		cmd.arg |= blocks;
+	} else
+		cmd.arg |= (blksz == 512) ? 0 : blksz;
+
 	cmd.flags = MMC_RSP_R5 | MMC_CMD_ADTC;
 
-	data.blksz = size;
-	data.blocks = 1;
+	data.blksz = blksz;
+	data.blocks = blocks;
 	data.flags = write ? MMC_DATA_WRITE : MMC_DATA_READ;
 	data.sg = &sg;
 	data.sg_len = 1;
 
-	sg_init_one(&sg, buf, size);
+	sg_init_one(&sg, buf, blksz * blocks);
 
 	mmc_set_data_timeout(&data, card, 0);
 
diff --git a/drivers/mmc/core/sdio_ops.h b/drivers/mmc/core/sdio_ops.h
index 1d42e4f..e2e74b0 100644
--- a/drivers/mmc/core/sdio_ops.h
+++ b/drivers/mmc/core/sdio_ops.h
@@ -16,7 +16,7 @@ int mmc_send_io_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr);
 int mmc_io_rw_direct(struct mmc_card *card, int write, unsigned fn,
 	unsigned addr, u8 in, u8* out);
 int mmc_io_rw_extended(struct mmc_card *card, int write, unsigned fn,
-	unsigned addr, int bang, u8 *data, unsigned size);
+	unsigned addr, int incr_addr, u8 *buf, unsigned blocks, unsigned blksz);
 
 #endif
 
diff --git a/include/linux/mmc/sdio_func.h b/include/linux/mmc/sdio_func.h
index 14d9147..8bdbb3b 100644
--- a/include/linux/mmc/sdio_func.h
+++ b/include/linux/mmc/sdio_func.h
@@ -43,7 +43,9 @@ struct sdio_func {
 	unsigned short		vendor;		/* vendor id */
 	unsigned short		device;		/* device id */
 
-	unsigned short		blksize;	/* maximum block size */
+	unsigned short		max_blksz;	/* maximum block size */
+	unsigned short		cur_blksz;	/* current block size */
+	unsigned short		forced_blksz;	/* driver forced block size */
 
 	unsigned int		state;		/* function state */
 #define SDIO_STATE_PRESENT	(1<<0)		/* present in sysfs */
@@ -136,5 +138,7 @@ extern int sdio_memcpy_toio(struct sdio_func *func, unsigned int addr,
 extern int sdio_writesb(struct sdio_func *func, unsigned int addr,
 	void *src, int count);
 
+extern int sdio_force_block_size(struct sdio_func *func, unsigned short size);
+
 #endif
 

-- 
     -- Pierre Ossman

  Linux kernel, MMC maintainer        http://www.kernel.org
  PulseAudio, core developer          http://pulseaudio.org
  rdesktop, core developer          http://www.rdesktop.org
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