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@@ -51,6 +51,7 @@ struct exynos_spi_slave {
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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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unsigned int fifo_size;
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+ int skip_preamble;
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};
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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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spi_slave->fifo_size = 256;
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+ spi_slave->skip_preamble = 0;
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+
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spi_slave->freq = bus->frequency;
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if (max_hz)
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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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}
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-static void spi_rx_tx(struct exynos_spi_slave *spi_slave, int todo,
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- void **dinp, void const **doutp)
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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, unsigned long flags)
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{
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struct exynos_spi *regs = spi_slave->regs;
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uchar *rxp = *dinp;
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const uchar *txp = *doutp;
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int rx_lvl, tx_lvl;
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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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+ 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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* 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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* data because then transmission will be done as well.
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*/
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+ toread = in_bytes;
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+
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while (in_bytes) {
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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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out_bytes--;
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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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- if (rxp)
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- *rxp++ = temp;
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- in_bytes--;
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+ if (spi_slave->skip_preamble) {
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+ if (temp == SPI_PREAMBLE_END_BYTE) {
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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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*dinp = rxp;
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*doutp = txp;
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+
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+ return 0;
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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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int upto, todo;
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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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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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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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- 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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/* 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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+ 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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@@ -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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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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