diff options
Diffstat (limited to 'src/cpu/samsung')
| -rw-r--r-- | src/cpu/samsung/exynos5420/spi.c | 115 |
1 files changed, 56 insertions, 59 deletions
diff --git a/src/cpu/samsung/exynos5420/spi.c b/src/cpu/samsung/exynos5420/spi.c index dddbec5dfc..906f6a7afa 100644 --- a/src/cpu/samsung/exynos5420/spi.c +++ b/src/cpu/samsung/exynos5420/spi.c @@ -153,10 +153,8 @@ static void exynos_spi_request_bytes(struct exynos_spi *regs, int count, } } -int spi_rx_tx(struct spi_slave *slave, uint8_t *rxp, int rx_bytes, - const uint8_t *txp, int tx_bytes); -int spi_rx_tx(struct spi_slave *slave, uint8_t *rxp, int rx_bytes, - const uint8_t *txp, int tx_bytes) +static int spi_rx_tx(struct spi_slave *slave, uint8_t *rxp, int rx_bytes, + const uint8_t *txp, int tx_bytes) { struct exynos_spi_slave *espi = to_exynos_spi(slave); struct exynos_spi *regs = espi->regs; @@ -237,46 +235,6 @@ int spi_rx_tx(struct spi_slave *slave, uint8_t *rxp, int rx_bytes, return 0; } -static void exynos_spi_rx_tx(struct exynos_spi *regs, int todo, - void *dinp, void const *doutp, int i) -{ - int rx_lvl, tx_lvl; - unsigned int *rxp = (unsigned int *)(dinp + (i * (32 * 1024))); - unsigned int out_bytes, in_bytes; - - // TODO In currrent implementation, every read/write must be aligned to - // 4 bytes, otherwise you may get timeout or other unexpected results. - ASSERT(todo % 4 == 0); - - out_bytes = in_bytes = todo; - exynos_spi_soft_reset(regs); - writel(((todo * 8) / 32) | SPI_PACKET_CNT_EN, ®s->pkt_cnt); - - while (in_bytes) { - uint32_t spi_sts; - int temp; - - spi_sts = readl(®s->spi_sts); - rx_lvl = ((spi_sts >> 15) & 0x7f); - tx_lvl = ((spi_sts >> 6) & 0x7f); - while (tx_lvl < 32 && out_bytes) { - // TODO The "writing" (tx) is not supported now; that's - // why we write garbage to keep driving FIFO clock. - temp = 0xffffffff; - writel(temp, ®s->tx_data); - out_bytes -= 4; - tx_lvl += 4; - } - while (rx_lvl >= 4 && in_bytes) { - temp = readl(®s->rx_data); - if (rxp) - *rxp++ = temp; - in_bytes -= 4; - rx_lvl -= 4; - } - } -} - int spi_claim_bus(struct spi_slave *slave) { struct exynos_spi_slave *espi = to_exynos_spi(slave); @@ -304,32 +262,70 @@ int spi_claim_bus(struct spi_slave *slave) int spi_xfer(struct spi_slave *slave, const void *dout, unsigned int bitsout, void *din, unsigned int bitsin) { - // TODO(hungte) Invoke exynos_spi_rx_tx to transfer data. - return -1; + unsigned int out_bytes = bitsout / 8, in_bytes = bitsin / 8; + uint8_t *out_ptr = (uint8_t *)dout, *in_ptr = (uint8_t *)din; + int offset, todo, len; + int ret = 0; + + ASSERT(bitsout % 8 == 0 && bitsin % 8 == 0); + len = MAX(out_bytes, in_bytes); + + /* + * Exynos SPI limits each transfer to (2^16-1=65535) bytes. To keep + * things simple (especially for word-width transfer mode), allow a + * maximum of (2^16-4=65532) bytes. We could allow more in word mode, + * but the performance difference is small. + */ + spi_cs_activate(slave); + for (offset = 0; !ret && (offset < len); offset += todo) { + todo = min(len - offset, (1 << 16) - 4); + ret = spi_rx_tx(slave, in_ptr, MIN(in_bytes, todo), out_ptr, + MIN(out_bytes, todo)); + // Adjust remaining bytes and pointers. + if (in_bytes >= todo) { + in_bytes -= todo; + in_ptr += todo; + } else { + in_bytes = 0; + in_ptr = NULL; + } + if (out_bytes >= todo) { + out_bytes -= todo; + out_ptr += todo; + } else { + out_bytes = 0; + out_ptr = NULL; + } + } + spi_cs_deactivate(slave); + + return ret; } static int exynos_spi_read(struct spi_slave *slave, void *dest, uint32_t len, uint32_t off) { struct exynos_spi *regs = to_exynos_spi(slave)->regs; - int upto, todo; - int i; - clrbits_le32(®s->cs_reg, SPI_SLAVE_SIG_INACT); /* CS low */ + int rv; - /* Send read instruction (0x3h) followed by a 24 bit addr */ - writel((SF_READ_DATA_CMD << 24) | off, ®s->tx_data); + // TODO(hungte) Merge the "read address" command into spi_xfer calls + // (full-duplex mode). - /* waiting for TX done */ - while (!(readl(®s->spi_sts) & SPI_ST_TX_DONE)); + spi_cs_activate(slave); - for (upto = 0, i = 0; upto < len; upto += todo, i++) { - todo = MIN(len - upto, (1 << 15)); - exynos_spi_rx_tx(regs, todo, dest, (void *)(off), i); + // Specify read address (in word-width mode). + ASSERT(off < (1 << 24)); + exynos_spi_request_bytes(regs, sizeof(off), sizeof(off)); + writel(htonl((SF_READ_DATA_CMD << 24) | off), ®s->tx_data); + while (!(readl(®s->spi_sts) & SPI_ST_TX_DONE)) { + /* Wait for TX done */ } - setbits_le32(®s->cs_reg, SPI_SLAVE_SIG_INACT);/* make the CS high */ + // Now, safe to transfer. + rv = spi_xfer(slave, NULL, 0, dest, len * 8); + spi_cs_deactivate(slave); - return len; + return (rv == 0) ? len : -1; } void spi_release_bus(struct spi_slave *slave) @@ -378,7 +374,8 @@ static void *exynos_spi_cbfs_map(struct cbfs_media *media, size_t offset, size_t count) { struct exynos_spi_media *spi = (struct exynos_spi_media*)media->context; DEBUG_SPI("exynos_spi_cbfs_map\n"); - // See exynos_spi_rx_tx for I/O alignment limitation. + // exynos: spi_rx_tx may work in 4 byte-width-transmission mode and + // requires buffer memory address to be aligned. if (count % 4) count += 4 - (count % 4); return cbfs_simple_buffer_map(&spi->buffer, media, offset, count); |