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https://github.com/brain-hackers/u-boot-brain
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spi: exynos: Support SPI_PREAMBLE mode
Support interfaces with a preamble before each received message. We handle this when the client has requested a SPI_XFER_END, meaning that we must close of the transaction. In this case we read until we see the preamble (or a timeout occurs), skipping all data before and including the preamble. The client will receive only data bytes after the preamble. Signed-off-by: Simon Glass <sjg@chromium.org> Signed-off-by: Rajeshwari Shinde <rajeshwari.s@samsung.com> Reviewed-by: Jagannadha Sutradharudu Teki <jagannadh.teki@gmail.com>
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@ -51,6 +51,7 @@ struct exynos_spi_slave {
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unsigned int mode;
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unsigned int mode;
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enum periph_id periph_id; /* Peripheral ID for this device */
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enum periph_id periph_id; /* Peripheral ID for this device */
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unsigned int fifo_size;
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unsigned int fifo_size;
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int skip_preamble;
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};
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};
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static struct spi_bus *spi_get_bus(unsigned dev_index)
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static struct spi_bus *spi_get_bus(unsigned dev_index)
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@ -105,6 +106,8 @@ struct spi_slave *spi_setup_slave(unsigned int busnum, unsigned int cs,
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else
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else
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spi_slave->fifo_size = 256;
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spi_slave->fifo_size = 256;
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spi_slave->skip_preamble = 0;
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spi_slave->freq = bus->frequency;
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spi_slave->freq = bus->frequency;
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if (max_hz)
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if (max_hz)
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spi_slave->freq = min(max_hz, spi_slave->freq);
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spi_slave->freq = min(max_hz, spi_slave->freq);
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@ -217,17 +220,23 @@ static void spi_request_bytes(struct exynos_spi *regs, int count)
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writel(count | SPI_PACKET_CNT_EN, ®s->pkt_cnt);
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writel(count | SPI_PACKET_CNT_EN, ®s->pkt_cnt);
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}
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}
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static void spi_rx_tx(struct exynos_spi_slave *spi_slave, int todo,
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static int spi_rx_tx(struct exynos_spi_slave *spi_slave, int todo,
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void **dinp, void const **doutp)
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void **dinp, void const **doutp, unsigned long flags)
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{
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{
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struct exynos_spi *regs = spi_slave->regs;
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struct exynos_spi *regs = spi_slave->regs;
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uchar *rxp = *dinp;
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uchar *rxp = *dinp;
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const uchar *txp = *doutp;
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const uchar *txp = *doutp;
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int rx_lvl, tx_lvl;
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int rx_lvl, tx_lvl;
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uint out_bytes, in_bytes;
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uint out_bytes, in_bytes;
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int toread;
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unsigned start = get_timer(0);
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int stopping;
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out_bytes = in_bytes = todo;
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out_bytes = in_bytes = todo;
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stopping = spi_slave->skip_preamble && (flags & SPI_XFER_END) &&
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!(spi_slave->mode & SPI_SLAVE);
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/*
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/*
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* If there's something to send, do a software reset and set a
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* If there's something to send, do a software reset and set a
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* transaction size.
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* transaction size.
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@ -238,6 +247,8 @@ static void spi_rx_tx(struct exynos_spi_slave *spi_slave, int todo,
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* Bytes are transmitted/received in pairs. Wait to receive all the
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* Bytes are transmitted/received in pairs. Wait to receive all the
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* data because then transmission will be done as well.
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* data because then transmission will be done as well.
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*/
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*/
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toread = in_bytes;
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while (in_bytes) {
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while (in_bytes) {
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int temp;
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int temp;
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@ -248,15 +259,43 @@ static void spi_rx_tx(struct exynos_spi_slave *spi_slave, int todo,
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writel(temp, ®s->tx_data);
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writel(temp, ®s->tx_data);
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out_bytes--;
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out_bytes--;
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}
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}
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if (rx_lvl > 0 && in_bytes) {
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if (rx_lvl > 0) {
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temp = readl(®s->rx_data);
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temp = readl(®s->rx_data);
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if (rxp)
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if (spi_slave->skip_preamble) {
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*rxp++ = temp;
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if (temp == SPI_PREAMBLE_END_BYTE) {
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in_bytes--;
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spi_slave->skip_preamble = 0;
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stopping = 0;
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}
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} else {
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if (rxp || stopping)
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*rxp++ = temp;
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in_bytes--;
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}
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toread--;
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} else if (!toread) {
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/*
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* We have run out of input data, but haven't read
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* enough bytes after the preamble yet. Read some more,
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* and make sure that we transmit dummy bytes too, to
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* keep things going.
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*/
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assert(!out_bytes);
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out_bytes = in_bytes;
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toread = in_bytes;
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txp = NULL;
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spi_request_bytes(regs, toread);
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}
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if (spi_slave->skip_preamble && get_timer(start) > 100) {
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printf("SPI timeout: in_bytes=%d, out_bytes=%d, ",
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in_bytes, out_bytes);
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return -1;
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}
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}
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}
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}
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*dinp = rxp;
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*dinp = rxp;
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*doutp = txp;
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*doutp = txp;
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return 0;
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}
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}
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/**
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/**
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@ -276,6 +315,7 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
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struct exynos_spi_slave *spi_slave = to_exynos_spi(slave);
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struct exynos_spi_slave *spi_slave = to_exynos_spi(slave);
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int upto, todo;
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int upto, todo;
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int bytelen;
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int bytelen;
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int ret = 0;
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/* spi core configured to do 8 bit transfers */
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/* spi core configured to do 8 bit transfers */
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if (bitlen % 8) {
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if (bitlen % 8) {
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@ -289,16 +329,24 @@ int spi_xfer(struct spi_slave *slave, unsigned int bitlen, const void *dout,
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/* Exynos SPI limits each transfer to 65535 bytes */
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/* Exynos SPI limits each transfer to 65535 bytes */
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bytelen = bitlen / 8;
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bytelen = bitlen / 8;
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for (upto = 0; upto < bytelen; upto += todo) {
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for (upto = 0; !ret && upto < bytelen; upto += todo) {
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todo = min(bytelen - upto, (1 << 16) - 1);
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todo = min(bytelen - upto, (1 << 16) - 1);
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spi_rx_tx(spi_slave, todo, &din, &dout);
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ret = spi_rx_tx(spi_slave, todo, &din, &dout, flags);
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if (ret)
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break;
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}
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}
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/* Stop the transaction, if necessary. */
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/* Stop the transaction, if necessary. */
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if ((flags & SPI_XFER_END))
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if ((flags & SPI_XFER_END) && !(spi_slave->mode & SPI_SLAVE)) {
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spi_cs_deactivate(slave);
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spi_cs_deactivate(slave);
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if (spi_slave->skip_preamble) {
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assert(!spi_slave->skip_preamble);
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debug("Failed to complete premable transaction\n");
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ret = -1;
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}
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}
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return 0;
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return ret;
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}
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}
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/**
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/**
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@ -325,6 +373,7 @@ void spi_cs_activate(struct spi_slave *slave)
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clrbits_le32(&spi_slave->regs->cs_reg, SPI_SLAVE_SIG_INACT);
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clrbits_le32(&spi_slave->regs->cs_reg, SPI_SLAVE_SIG_INACT);
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debug("Activate CS, bus %d\n", spi_slave->slave.bus);
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debug("Activate CS, bus %d\n", spi_slave->slave.bus);
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spi_slave->skip_preamble = spi_slave->mode & SPI_PREAMBLE;
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}
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}
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/**
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/**
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