diff options
Diffstat (limited to 'src/soc/nvidia/tegra210/spi.c')
| -rw-r--r-- | src/soc/nvidia/tegra210/spi.c | 99 |
1 files changed, 41 insertions, 58 deletions
diff --git a/src/soc/nvidia/tegra210/spi.c b/src/soc/nvidia/tegra210/spi.c index ffb4d47c70..5946ef078b 100644 --- a/src/soc/nvidia/tegra210/spi.c +++ b/src/soc/nvidia/tegra210/spi.c @@ -212,12 +212,6 @@ static struct tegra_spi_channel * const to_tegra_spi(int bus) { return &tegra_spi_channels[bus - 1]; } -static unsigned int tegra_spi_speed(unsigned int bus) -{ - /* FIXME: implement this properly, for now use max value (50MHz) */ - return 50000000; -} - int spi_claim_bus(struct spi_slave *slave) { struct tegra_spi_regs *regs = to_tegra_spi(slave->bus)->regs; @@ -329,36 +323,22 @@ static inline unsigned int spi_byte_count(struct tegra_spi_channel *spi) (SPI_STATUS_BLOCK_COUNT << SPI_STATUS_BLOCK_COUNT_SHIFT); } -/* - * This calls udelay() with a calculated value based on the SPI speed and - * number of bytes remaining to be transferred. It assumes that if the - * calculated delay period is less than MIN_DELAY_US then it is probably - * not worth the overhead of yielding. - */ -#define MIN_DELAY_US 250 -static void spi_delay(struct tegra_spi_channel *spi, - unsigned int bytes_remaining) -{ - unsigned int ns_per_byte, delay_us; - - ns_per_byte = 1000000000 / (tegra_spi_speed(spi->slave.bus) / 8); - delay_us = (ns_per_byte * bytes_remaining) / 1000; - - if (delay_us < MIN_DELAY_US) - return; - - udelay(delay_us); -} - static void tegra_spi_wait(struct tegra_spi_channel *spi) { - unsigned int count, dma_blk; + uint32_t dma_blk_count = 1 + (read32(&spi->regs->dma_blk) & + (SPI_DMA_CTL_BLOCK_SIZE_MASK << + SPI_DMA_CTL_BLOCK_SIZE_SHIFT)); - dma_blk = 1 + (read32(&spi->regs->dma_blk) & - (SPI_DMA_CTL_BLOCK_SIZE_MASK << SPI_DMA_CTL_BLOCK_SIZE_SHIFT)); + while ((read32(&spi->regs->trans_status) & SPI_STATUS_RDY) != + SPI_STATUS_RDY) + ; - while ((count = spi_byte_count(spi)) != dma_blk) - spi_delay(spi, dma_blk - count); + /* + * If RDY bit is set, we should never encounter the condition that + * blocks processed is not equal to the number programmed in dma_blk + * register. + */ + ASSERT(spi_byte_count(spi) == dma_blk_count); } @@ -367,24 +347,32 @@ static int fifo_error(struct tegra_spi_channel *spi) return read32(&spi->regs->fifo_status) & SPI_FIFO_STATUS_ERR ? 1 : 0; } +static void flush_fifos(struct tegra_spi_channel *spi) +{ + const uint32_t flush_mask = SPI_FIFO_STATUS_TX_FIFO_FLUSH | + SPI_FIFO_STATUS_RX_FIFO_FLUSH; + + uint32_t fifo_status = read32(&spi->regs->fifo_status); + fifo_status |= flush_mask; + write32(&spi->regs->fifo_status, flush_mask); + + while (read32(&spi->regs->fifo_status) & flush_mask) + ; +} + static int tegra_spi_pio_prepare(struct tegra_spi_channel *spi, unsigned int bytes, enum spi_direction dir) { u8 *p = spi->out_buf; unsigned int todo = MIN(bytes, SPI_MAX_TRANSFER_BYTES_FIFO); - u32 flush_mask, enable_mask; + u32 enable_mask; - if (dir == SPI_SEND) { - flush_mask = SPI_FIFO_STATUS_TX_FIFO_FLUSH; + flush_fifos(spi); + + if (dir == SPI_SEND) enable_mask = SPI_CMD1_TX_EN; - } else { - flush_mask = SPI_FIFO_STATUS_RX_FIFO_FLUSH; + else enable_mask = SPI_CMD1_RX_EN; - } - - setbits_le32(&spi->regs->fifo_status, flush_mask); - while (read32(&spi->regs->fifo_status) & flush_mask) - ; /* * BLOCK_SIZE in SPI_DMA_BLK register applies to both DMA and @@ -439,24 +427,17 @@ static inline u32 rx_fifo_count(struct tegra_spi_channel *spi) static int tegra_spi_pio_finish(struct tegra_spi_channel *spi) { u8 *p = spi->in_buf; - struct stopwatch sw; clrbits_le32(&spi->regs->command1, SPI_CMD1_RX_EN | SPI_CMD1_TX_EN); - /* - * Allow some time in case the Rx FIFO does not yet have - * all packets pushed into it. See chrome-os-partner:24215. - */ - stopwatch_init_usecs_expire(&sw, SPI_FIFO_XFER_TIMEOUT_US); - do { - if (rx_fifo_count(spi) == spi_byte_count(spi)) - break; - } while (!stopwatch_expired(&sw)); + ASSERT(rx_fifo_count(spi) == spi_byte_count(spi)); - while (!(read32(&spi->regs->fifo_status) & - SPI_FIFO_STATUS_RX_FIFO_EMPTY)) { - *p = read8(&spi->regs->rx_fifo); - p++; + if (p) { + while (!(read32(&spi->regs->fifo_status) & + SPI_FIFO_STATUS_RX_FIFO_EMPTY)) { + *p = read8(&spi->regs->rx_fifo); + p++; + } } if (fifo_error(spi)) { @@ -509,6 +490,8 @@ static int tegra_spi_dma_prepare(struct tegra_spi_channel *spi, todo = ALIGN_DOWN(todo, TEGRA_DMA_ALIGN_BYTES); wcount = ALIGN_DOWN(todo - TEGRA_DMA_ALIGN_BYTES, TEGRA_DMA_ALIGN_BYTES); + flush_fifos(spi); + if (dir == SPI_SEND) { spi->dma_out = dma_claim(); if (!spi->dma_out) @@ -605,7 +588,7 @@ static int tegra_spi_dma_finish(struct tegra_spi_channel *spi) if (spi->dma_in) { while ((read32(&spi->dma_in->regs->dma_byte_sta) < todo) || dma_busy(spi->dma_in)) - ; /* this shouldn't take long, no udelay */ + ; dma_stop(spi->dma_in); clrbits_le32(&spi->regs->command1, SPI_CMD1_RX_EN); /* Disable secure access for the channel. */ @@ -617,7 +600,7 @@ static int tegra_spi_dma_finish(struct tegra_spi_channel *spi) if (spi->dma_out) { while ((read32(&spi->dma_out->regs->dma_byte_sta) < todo) || dma_busy(spi->dma_out)) - spi_delay(spi, todo - spi_byte_count(spi)); + ; clrbits_le32(&spi->regs->command1, SPI_CMD1_TX_EN); dma_stop(spi->dma_out); /* Disable secure access for the channel. */ |