[U-Boot] [UBOOT PATCH v2 2/3] spi: xilinx_spi: Modify transfer logic xilinx_spi_xfer() function

12 Jun 2018

This patch modify xilinx_spi_xfer() function and add rxfifo() and
txfifo() functions to add the modularity.
Signed-off-by: Vipul Kumar vipul.kumar@xilinx.com
Signed-off-by: Siva Durga Prasad Paladugu siva.durga.paladugu@xilinx.com
---
 drivers/spi/xilinx_spi.c | 98 +++++++++++++++++++++++++++++++-----------------
 1 file changed, 63 insertions(+), 35 deletions(-)

diff --git a/drivers/spi/xilinx_spi.c b/drivers/spi/xilinx_spi.c
index 615106b..70a110a 100644
--- a/drivers/spi/xilinx_spi.c
+++ b/drivers/spi/xilinx_spi.c
@@ -19,6 +19,7 @@
 #include <malloc.h>
 #include <spi.h>
 #include <asm/io.h>
+#include <wait_bit.h>
/*
  * [0]: http://www.xilinx.com/support/documentation
@@ -77,6 +78,8 @@
 #define CONFIG_XILINX_SPI_IDLE_VAL     GENMASK(7, 0)
 #endif
+#define XILINX_SPISR_TIMEOUT   10000 /* in milliseconds */
+
 /* xilinx spi register set */
 struct xilinx_spi_regs {
        u32 __space0__[7];
@@ -156,6 +159,46 @@ static int xilinx_spi_release_bus(struct udevice *dev)
        return 0;
 }
+static u32 xilinx_spi_fill_txfifo(struct udevice *bus, const u8 *txp,
+                                 u32 txbytes)
+{
+       struct xilinx_spi_priv *priv = dev_get_priv(bus);
+       struct xilinx_spi_regs *regs = priv->regs;
+       unsigned char d;
+       u32 i = 0;
+
+       while (txbytes && !(readl(&regs->spisr) & SPISR_TX_FULL) &&
+              i < priv->fifo_depth) {
+               d = txp ? *txp++ : CONFIG_XILINX_SPI_IDLE_VAL;
+               debug("spi_xfer: tx:%x ", d);
+               /* write out and wait for processing (receive data) */
+               writel(d & SPIDTR_8BIT_MASK, &regs->spidtr);
+               txbytes--;
+               i++;
+       }
+       return i;
+}
+
+static u32 xilinx_spi_read_rxfifo(struct udevice *bus, u8 *rxp, u32 rxbytes)
+{
+       struct xilinx_spi_priv *priv = dev_get_priv(bus);
+       struct xilinx_spi_regs *regs = priv->regs;
+       unsigned char d;
+       unsigned int i = 0;
+
+       while (rxbytes && !(readl(&regs->spisr) & SPISR_RX_EMPTY)) {
+               d = readl(&regs->spidrr) & SPIDRR_8BIT_MASK;
+               if (rxp)
+                       *rxp++ = d;
+               debug("spi_xfer: rx:%x\n", d);
+               rxbytes--;
+               i++;
+       }
+       debug("Rx_done\n");
+
+       return i;
+}
+
 static int xilinx_spi_xfer(struct udevice *dev, unsigned int bitlen,
                            const void *dout, void *din, unsigned long flags)
 {
@@ -167,8 +210,10 @@ static int xilinx_spi_xfer(struct udevice *dev, unsigned int bitlen,
        unsigned int bytes = bitlen / XILSPI_MAX_XFER_BITS;
        const unsigned char *txp = dout;
        unsigned char *rxp = din;
-       unsigned rxecount = 17; /* max. 16 elements in FIFO, leftover 1 */
-       unsigned global_timeout;
+       u32 txbytes = bytes;
+       u32 rxbytes = bytes;
+       u32 reg, count, timeout;
+       int ret;
debug("spi_xfer: bus:%i cs:%i bitlen:%i bytes:%i flags:%lx\n",
              bus->seq, slave_plat->cs, bitlen, bytes, flags);
@@ -183,48 +228,31 @@ static int xilinx_spi_xfer(struct udevice *dev, unsigned int bitlen,
                goto done;
        }
-       /* empty read buffer */
-       while (rxecount && !(readl(&regs->spisr) & SPISR_RX_EMPTY)) {
-               readl(&regs->spidrr);
-               rxecount--;
-       }
-
-       if (!rxecount) {
-               printf("XILSPI error: Rx buffer not empty\n");
-               return -1;
-       }
-
        if (flags & SPI_XFER_BEGIN)
                spi_cs_activate(dev, slave_plat->cs);
-       /* at least 1usec or greater, leftover 1 */
-       global_timeout = priv->freq > XILSPI_MAX_XFER_BITS * 1000000 ? 2 :
-                       (XILSPI_MAX_XFER_BITS * 1000000 / priv->freq) + 1;
-       while (bytes--) {
-               unsigned timeout = global_timeout;
-               /* get Tx element from data out buffer and count up */
-               unsigned char d = txp ? *txp++ : CONFIG_XILINX_SPI_IDLE_VAL;
-               debug("spi_xfer: tx:%x ", d);
-
-               /* write out and wait for processing (receive data) */
-               writel(d & SPIDTR_8BIT_MASK, &regs->spidtr);
-               while (timeout && readl(&regs->spisr)
-                                               & SPISR_RX_EMPTY) {
-                       timeout--;
-                       udelay(1);
-               }
+       while (txbytes && rxbytes) {
+               count = xilinx_spi_fill_txfifo(bus, txp, txbytes);
+               reg = readl(&regs->spicr) & ~SPICR_MASTER_INHIBIT;
+               writel(reg, &regs->spicr);
+               txbytes -= count;
+               if (txp)
+                       txp += count;
-               if (!timeout) {
+               ret = wait_for_bit_le32(&regs->spisr, SPISR_TX_EMPTY, true,
+                                       XILINX_SPISR_TIMEOUT, false);
+               if (ret < 0) {
                        printf("XILSPI error: Xfer timeout\n");
-                       return -1;
+                       return ret;
                }
-               /* read Rx element and push into data in buffer */
-               d = readl(&regs->spidrr) & SPIDRR_8BIT_MASK;
+               debug("txbytes:0x%x,txp:0x%p\n", txbytes, txp);
+               count = xilinx_spi_read_rxfifo(bus, rxp, rxbytes);
+               rxbytes -= count;
                if (rxp)
-                       *rxp++ = d;
-               debug("spi_xfer: rx:%x\n", d);
+                       rxp += count;
+               debug("rxbytes:0x%x rxp:0x%p\n", rxbytes, rxp);
        }
done:
--
2.7.4
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