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authorJonatas Rech <jonatas.rech@datacom.ind.br>2015-04-15 12:23:18 -0300
committerMark Brown <broonie@kernel.org>2015-04-25 14:00:09 +0100
commit2000058e892cd6773b3061a56c0bd6535ac15afe (patch)
tree037b3d1922e56e05c5082cc710725b9cce223a11 /drivers/spi
parentc517d838eb7d07bbe9507871fab3931deccff539 (diff)
spi: fsl-espi: fix behaviour for full-duplex xfers
This patch makes possible for protocol drivers to do full-duplex SPI transfers properly. Until now this driver could only be used for half-duplex transfers, since it always expected an spi_transfer with non-null tx_buf to be only used for TX, and those with non-null rx_buf to be only used for RX. The fix consists in correcting the fsl_espi_transfer length by taking into consideration duplex spi_transfers, and not just by adding n_tx and n_rx. Furthermore, this correction has exposed an inconsistency in the protocol driver <-> controller driver interaction. The spi-fsl-espi driver artificially inserts TX bytes when message fragmentation is necessary (due to SPCOM_TRANLEN_MAX) instead of informing the protocol driver of the hardware limitation. This was tested with the m25p80 NOR flash protocol driver. Since fixing this issue may cause other client drivers to malfunction, it was left as is. Signed-off-by: Jonatas Rech <jonatas.rech@datacom.ind.br> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers/spi')
-rw-r--r--drivers/spi/spi-fsl-espi.c45
1 files changed, 31 insertions, 14 deletions
diff --git a/drivers/spi/spi-fsl-espi.c b/drivers/spi/spi-fsl-espi.c
index d0a73a09a9bd..80d245ac846f 100644
--- a/drivers/spi/spi-fsl-espi.c
+++ b/drivers/spi/spi-fsl-espi.c
@@ -359,14 +359,16 @@ static void fsl_espi_rw_trans(struct spi_message *m,
struct fsl_espi_transfer *trans, u8 *rx_buff)
{
struct fsl_espi_transfer *espi_trans = trans;
- unsigned int n_tx = espi_trans->n_tx;
- unsigned int n_rx = espi_trans->n_rx;
+ unsigned int total_len = espi_trans->len;
struct spi_transfer *t;
u8 *local_buf;
u8 *rx_buf = rx_buff;
unsigned int trans_len;
unsigned int addr;
- int i, pos, loop;
+ unsigned int tx_only;
+ unsigned int rx_pos = 0;
+ unsigned int pos;
+ int i, loop;
local_buf = kzalloc(SPCOM_TRANLEN_MAX, GFP_KERNEL);
if (!local_buf) {
@@ -374,36 +376,48 @@ static void fsl_espi_rw_trans(struct spi_message *m,
return;
}
- for (pos = 0, loop = 0; pos < n_rx; pos += trans_len, loop++) {
- trans_len = n_rx - pos;
- if (trans_len > SPCOM_TRANLEN_MAX - n_tx)
- trans_len = SPCOM_TRANLEN_MAX - n_tx;
+ for (pos = 0, loop = 0; pos < total_len; pos += trans_len, loop++) {
+ trans_len = total_len - pos;
i = 0;
+ tx_only = 0;
list_for_each_entry(t, &m->transfers, transfer_list) {
if (t->tx_buf) {
memcpy(local_buf + i, t->tx_buf, t->len);
i += t->len;
+ if (!t->rx_buf)
+ tx_only += t->len;
}
}
+ /* Add additional TX bytes to compensate SPCOM_TRANLEN_MAX */
+ if (loop > 0)
+ trans_len += tx_only;
+
+ if (trans_len > SPCOM_TRANLEN_MAX)
+ trans_len = SPCOM_TRANLEN_MAX;
+
+ /* Update device offset */
if (pos > 0) {
addr = fsl_espi_cmd2addr(local_buf);
- addr += pos;
+ addr += rx_pos;
fsl_espi_addr2cmd(addr, local_buf);
}
- espi_trans->n_tx = n_tx;
- espi_trans->n_rx = trans_len;
- espi_trans->len = trans_len + n_tx;
+ espi_trans->len = trans_len;
espi_trans->tx_buf = local_buf;
espi_trans->rx_buf = local_buf;
fsl_espi_do_trans(m, espi_trans);
- memcpy(rx_buf + pos, espi_trans->rx_buf + n_tx, trans_len);
+ /* If there is at least one RX byte then copy it to rx_buf */
+ if (tx_only < SPCOM_TRANLEN_MAX)
+ memcpy(rx_buf + rx_pos, espi_trans->rx_buf + tx_only,
+ trans_len - tx_only);
+
+ rx_pos += trans_len - tx_only;
if (loop > 0)
- espi_trans->actual_length += espi_trans->len - n_tx;
+ espi_trans->actual_length += espi_trans->len - tx_only;
else
espi_trans->actual_length += espi_trans->len;
}
@@ -418,6 +432,7 @@ static int fsl_espi_do_one_msg(struct spi_master *master,
u8 *rx_buf = NULL;
unsigned int n_tx = 0;
unsigned int n_rx = 0;
+ unsigned int xfer_len = 0;
struct fsl_espi_transfer espi_trans;
list_for_each_entry(t, &m->transfers, transfer_list) {
@@ -427,11 +442,13 @@ static int fsl_espi_do_one_msg(struct spi_master *master,
n_rx += t->len;
rx_buf = t->rx_buf;
}
+ if ((t->tx_buf) || (t->rx_buf))
+ xfer_len += t->len;
}
espi_trans.n_tx = n_tx;
espi_trans.n_rx = n_rx;
- espi_trans.len = n_tx + n_rx;
+ espi_trans.len = xfer_len;
espi_trans.actual_length = 0;
espi_trans.status = 0;