Add memory mapped flash read support. In memory mapped, only the len, from
and t->rx_buf is required from the flash side, while other configuration
will be taken care of from the respective controller side with the help
of the transfer flag(memory_map).
Signed-off-by: Sourav Poddar <sourav.pod...@ti.com>
---
drivers/mtd/devices/m25p80.c | 13 +++++++++++--
include/linux/spi/spi.h | 2 ++
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/drivers/mtd/devices/m25p80.c b/drivers/mtd/devices/m25p80.c
index dc9bcbf..9d09bad 100644
--- a/drivers/mtd/devices/m25p80.c
+++ b/drivers/mtd/devices/m25p80.c
@@ -102,6 +102,7 @@ struct m25p {
u8 *command;
bool fast_read;
bool quad_read;
+ bool mmap_read;
};
static inline struct m25p *mtd_to_m25p(struct mtd_info *mtd)
@@ -440,10 +441,15 @@ static int m25p80_quad_read(struct mtd_info *mtd, loff_t
from, size_t len,
spi_message_init(&m);
memset(t, 0, (sizeof(t)));
+ if (flash->mmap_read)
+ t[0].memory_map = 1;
t[0].tx_buf = flash->command;
- t[0].len = m25p_cmdsz(flash) + (flash->quad_read ? 1 : 0);
+ t[0].len = flash->mmap_read ? from : m25p_cmdsz(flash) +
+ (flash->quad_read ? 1 : 0);
spi_message_add_tail(&t[0], &m);
+ if (flash->mmap_read)
+ t[1].memory_map = 1;
t[1].rx_buf = buf;
t[1].len = len;
t[1].rx_nbits = SPI_NBITS_QUAD;
@@ -470,7 +476,7 @@ static int m25p80_quad_read(struct mtd_info *mtd, loff_t
from, size_t len,
spi_sync(flash->spi, &m);
- *retlen = m.actual_length - m25p_cmdsz(flash) -
+ *retlen = flash->mmap_read ? len : m.actual_length - m25p_cmdsz(flash) -
(flash->quad_read ? 1 : 0);
mutex_unlock(&flash->lock);
@@ -1207,6 +1213,9 @@ static int m25p_probe(struct spi_device *spi)
if (spi->mode && SPI_RX_QUAD)
flash->quad_read = true;
+ if (spi->mode && SPI_RX_MMAP)
+ flash->mmap_read = true;
+
flash->command = kmalloc(MAX_CMD_SIZE + (flash->fast_read ? 1 :
(flash->quad_read ? 1 : 0)), GFP_KERNEL);
if (!flash->command) {
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 4d634d6..a6ffb52 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -91,6 +91,7 @@ struct spi_device {
#define SPI_TX_QUAD 0x200 /* transmit with 4
wires */
#define SPI_RX_DUAL 0x400 /* receive with 2 wires
*/
#define SPI_RX_QUAD 0x800 /* receive with 4 wires
*/
+#define SPI_RX_MMAP 0x1000 /* Memory mapped read */
u8 bits_per_word;
int irq;
void *controller_state;
@@ -557,6 +558,7 @@ struct spi_transfer {
u16 delay_usecs;
u32 speed_hz;
+ bool memory_map;
struct list_head transfer_list;
};
--
1.7.1
------------------------------------------------------------------------------
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