diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/amba-pl022.c | 18 |
1 files changed, 12 insertions, 6 deletions
diff --git a/drivers/spi/amba-pl022.c b/drivers/spi/amba-pl022.c index ff5bbb9c43c9..9aeb68113100 100644 --- a/drivers/spi/amba-pl022.c +++ b/drivers/spi/amba-pl022.c @@ -363,6 +363,7 @@ struct pl022 { void *rx_end; enum ssp_reading read; enum ssp_writing write; + u32 exp_fifo_level; }; /** @@ -501,6 +502,9 @@ static int flush(struct pl022 *pl022) while (readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_RNE) readw(SSP_DR(pl022->virtbase)); } while ((readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_BSY) && limit--); + + pl022->exp_fifo_level = 0; + return limit; } @@ -583,10 +587,9 @@ static void readwriter(struct pl022 *pl022) * errons in 8bit wide transfers on ARM variants (just 8 words * FIFO, means only 8x8 = 64 bits in FIFO) at least. * - * FIXME: currently we have no logic to account for this. - * perhaps there is even something broken in HW regarding - * 8bit transfers (it doesn't fail on 16bit) so this needs - * more investigation... + * To prevent this issue, the TX FIFO is only filled to the + * unused RX FIFO fill length, regardless of what the TX + * FIFO status flag indicates. */ dev_dbg(&pl022->adev->dev, "%s, rx: %p, rxend: %p, tx: %p, txend: %p\n", @@ -613,11 +616,12 @@ static void readwriter(struct pl022 *pl022) break; } pl022->rx += (pl022->cur_chip->n_bytes); + pl022->exp_fifo_level--; } /* - * Write as much as you can, while keeping an eye on the RX FIFO! + * Write as much as possible up to the RX FIFO size */ - while ((readw(SSP_SR(pl022->virtbase)) & SSP_SR_MASK_TNF) + while ((pl022->exp_fifo_level < pl022->vendor->fifodepth) && (pl022->tx < pl022->tx_end)) { switch (pl022->write) { case WRITING_NULL: @@ -634,6 +638,7 @@ static void readwriter(struct pl022 *pl022) break; } pl022->tx += (pl022->cur_chip->n_bytes); + pl022->exp_fifo_level++; /* * This inner reader takes care of things appearing in the RX * FIFO as we're transmitting. This will happen a lot since the @@ -660,6 +665,7 @@ static void readwriter(struct pl022 *pl022) break; } pl022->rx += (pl022->cur_chip->n_bytes); + pl022->exp_fifo_level--; } } /* |