1 files changed, 109 insertions, 0 deletions
diff --git a/target/linux/ar71xx/patches-3.10/406-mtd-m25p80-allow-to-specify-max-read-size.patch b/target/linux/ar71xx/patches-3.10/406-mtd-m25p80-allow-to-specify-max-read-size.patch
new file mode 100644
index 0000000..3f9c182
--- /dev/null
+++ b/target/linux/ar71xx/patches-3.10/406-mtd-m25p80-allow-to-specify-max-read-size.patch
@@ -0,0 +1,109 @@
+--- a/drivers/mtd/devices/m25p80.c
++++ b/drivers/mtd/devices/m25p80.c
+@@ -93,6 +93,7 @@ struct m25p {
+ 	u8			erase_opcode;
+ 	u8			*command;
+ 	bool			fast_read;
++	size_t			max_read_len;
+ };
+ 
+ static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd)
+@@ -344,6 +345,7 @@ static int m25p80_read(struct mtd_info *
+ 	struct spi_transfer t[2];
+ 	struct spi_message m;
+ 	uint8_t opcode;
++	loff_t ofs;
+ 
+ 	pr_debug("%s: %s from 0x%08x, len %zd\n", dev_name(&flash->spi->dev),
+ 			__func__, (u32)from, len);
+@@ -359,19 +361,10 @@ static int m25p80_read(struct mtd_info *
+ 	t[0].len = m25p_cmdsz(flash) + (flash->fast_read ? 1 : 0);
+ 	spi_message_add_tail(&t[0], &m);
+ 
+-	t[1].rx_buf = buf;
+-	t[1].len = len;
+ 	spi_message_add_tail(&t[1], &m);
+ 
+ 	mutex_lock(&flash->lock);
+ 
+-	/* Wait till previous write/erase is done. */
+-	if (wait_till_ready(flash)) {
+-		/* REVISIT status return?? */
+-		mutex_unlock(&flash->lock);
+-		return 1;
+-	}
+-
+ 	/* FIXME switch to OPCODE_FAST_READ.  It's required for higher
+ 	 * clocks; and at this writing, every chip this driver handles
+ 	 * supports that opcode.
+@@ -380,13 +373,43 @@ static int m25p80_read(struct mtd_info *
+ 	/* Set up the write data buffer. */
+ 	opcode = flash->fast_read ? OPCODE_FAST_READ : OPCODE_NORM_READ;
+ 	flash->command[0] = opcode;
+-	m25p_addr2cmd(flash, from, flash->command);
++	ofs = 0;
++	while (len) {
++		size_t readlen;
++		size_t done;
++		int ret;
++
++		ret = wait_till_ready(flash);
++		if (ret) {
++			mutex_unlock(&flash->lock);
++			return 1;
++		}
++
++		if (flash->max_read_len > 0 &&
++		    flash->max_read_len < len)
++			readlen = flash->max_read_len;
++		else
++			readlen = len;
++
++		t[1].rx_buf = buf + ofs;
++		t[1].len = readlen;
++
++		m25p_addr2cmd(flash, from + ofs, flash->command);
++
++		spi_sync(flash->spi, &m);
+ 
+-	spi_sync(flash->spi, &m);
++		done = m.actual_length - m25p_cmdsz(flash) -
++		       (flash->fast_read ? 1 : 0);
++		if (done != readlen) {
++			mutex_unlock(&flash->lock);
++			return 1;
++		}
+ 
+-	*retlen = m.actual_length - m25p_cmdsz(flash) -
+-			(flash->fast_read ? 1 : 0);
++		ofs += done;
++		len -= done;
++	}
+ 
++	*retlen = ofs;
+ 	mutex_unlock(&flash->lock);
+ 
+ 	return 0;
+@@ -1021,6 +1044,12 @@ static int m25p_probe(struct spi_device 
+ 		flash->mtd._unlock = m25p80_unlock;
+ 	}
+ 
++	if (data && data->max_read_len) {
++		flash->max_read_len = data->max_read_len;
++		dev_warn(&spi->dev, "max_read_len set to %d bytes\n",
++			flash->max_read_len);
++	}
++
+ 	/* sst flash chips use AAI word program */
+ 	if (info->flags & SST_WRITE)
+ 		flash->mtd._write = sst_write;
+--- a/include/linux/spi/flash.h
++++ b/include/linux/spi/flash.h
+@@ -25,6 +25,7 @@ struct flash_platform_data {
+ 
+ 	char		*type;
+ 
++	size_t		max_read_len;
+ 	/* we'll likely add more ... use JEDEC IDs, etc */
+ };
+