spi: dw: Add mem_ops

The designware ssi device has "broken" chip select behaviour [1], and needs
specific manipulation to use the built-in chip select. The existing fix is
to use an external GPIO for chip select, but typically the K210 has SPI3
directly connected to a flash chip with dedicated pins. This makes it
impossible to use the spi_xfer function to use spi, since the CS is
de-asserted in between calls.  This patch adds an implementation of
exec_op, which gives correct behaviour when reading/writing spi flash.

This patch also rearranges the headers to conform to U-Boot style.

[1] https://lkml.org/lkml/2015/12/23/132

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Tested-by Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Reviewed-by: Jagan Teki <jagan@amarulasolutions.com>

diff --git a/drivers/spi/designware_spi.c b/drivers/spi/designware_spi.c
index 9e02fce..ce74ac0 100644 (file)
--- a/drivers/spi/designware_spi.c
+++ b/drivers/spi/designware_spi.c
@@ -12,21 +12,23 @@
 
 #define LOG_CATEGORY UCLASS_SPI
 #include <common.h>
-#include <log.h>
-#include <asm-generic/gpio.h>
 #include <clk.h>
 #include <dm.h>
+#include <dm/device_compat.h>
 #include <errno.h>
-#include <malloc.h>
-#include <spi.h>
 #include <fdtdec.h>
+#include <log.h>
+#include <malloc.h>
 #include <reset.h>
-#include <dm/device_compat.h>
-#include <linux/bitops.h>
+#include <spi.h>
+#include <spi-mem.h>
+#include <asm/io.h>
+#include <asm-generic/gpio.h>
 #include <linux/bitfield.h>
+#include <linux/bitops.h>
 #include <linux/compat.h>
 #include <linux/iopoll.h>
-#include <asm/io.h>
+#include <linux/sizes.h>
 
 /* Register offsets */
 #define DW_SPI_CTRLR0                  0x00
@@ -560,6 +562,107 @@ static int dw_spi_xfer(struct udevice *dev, unsigned int bitlen,
        return ret;
 }
 
+/*
+ * This function is necessary for reading SPI flash with the native CS
+ * c.f. https://lkml.org/lkml/2015/12/23/132
+ */
+static int dw_spi_exec_op(struct spi_slave *slave, const struct spi_mem_op *op)
+{
+       bool read = op->data.dir == SPI_MEM_DATA_IN;
+       int pos, i, ret = 0;
+       struct udevice *bus = slave->dev->parent;
+       struct dw_spi_priv *priv = dev_get_priv(bus);
+       u8 op_len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes;
+       u8 op_buf[op_len];
+       u32 cr0;
+
+       if (read)
+               priv->tmode = CTRLR0_TMOD_EPROMREAD;
+       else
+               priv->tmode = CTRLR0_TMOD_TO;
+
+       cr0 = priv->update_cr0(priv);
+       dev_dbg(bus, "cr0=%08x buf=%p len=%u [bytes]\n", cr0, op->data.buf.in,
+               op->data.nbytes);
+
+       dw_write(priv, DW_SPI_SSIENR, 0);
+       dw_write(priv, DW_SPI_CTRLR0, cr0);
+       if (read)
+               dw_write(priv, DW_SPI_CTRLR1, op->data.nbytes - 1);
+       dw_write(priv, DW_SPI_SSIENR, 1);
+
+       /* From spi_mem_exec_op */
+       pos = 0;
+       op_buf[pos++] = op->cmd.opcode;
+       if (op->addr.nbytes) {
+               for (i = 0; i < op->addr.nbytes; i++)
+                       op_buf[pos + i] = op->addr.val >>
+                               (8 * (op->addr.nbytes - i - 1));
+
+               pos += op->addr.nbytes;
+       }
+       if (op->dummy.nbytes)
+               memset(op_buf + pos, 0xff, op->dummy.nbytes);
+
+       external_cs_manage(slave->dev, false);
+
+       priv->tx = &op_buf;
+       priv->tx_end = priv->tx + op_len;
+       priv->rx = NULL;
+       priv->rx_end = NULL;
+       while (priv->tx != priv->tx_end)
+               dw_writer(priv);
+
+       /*
+        * XXX: The following are tight loops! Enabling debug messages may cause
+        * them to fail because we are not reading/writing the fifo fast enough.
+        */
+       if (read) {
+               priv->rx = op->data.buf.in;
+               priv->rx_end = priv->rx + op->data.nbytes;
+
+               dw_write(priv, DW_SPI_SER, 1 << spi_chip_select(slave->dev));
+               while (priv->rx != priv->rx_end)
+                       dw_reader(priv);
+       } else {
+               u32 val;
+
+               priv->tx = op->data.buf.out;
+               priv->tx_end = priv->tx + op->data.nbytes;
+
+               /* Fill up the write fifo before starting the transfer */
+               dw_writer(priv);
+               dw_write(priv, DW_SPI_SER, 1 << spi_chip_select(slave->dev));
+               while (priv->tx != priv->tx_end)
+                       dw_writer(priv);
+
+               if (readl_poll_timeout(priv->regs + DW_SPI_SR, val,
+                                      (val & SR_TF_EMPT) && !(val & SR_BUSY),
+                                      RX_TIMEOUT * 1000)) {
+                       ret = -ETIMEDOUT;
+               }
+       }
+
+       dw_write(priv, DW_SPI_SER, 0);
+       external_cs_manage(slave->dev, true);
+
+       dev_dbg(bus, "%u bytes xfered\n", op->data.nbytes);
+       return ret;
+}
+
+/* The size of ctrl1 limits data transfers to 64K */
+static int dw_spi_adjust_op_size(struct spi_slave *slave, struct spi_mem_op *op)
+{
+       op->data.nbytes = min(op->data.nbytes, (unsigned int)SZ_64K);
+
+       return 0;
+}
+
+static const struct spi_controller_mem_ops dw_spi_mem_ops = {
+       .exec_op = dw_spi_exec_op,
+       .adjust_op_size = dw_spi_adjust_op_size,
+};
+
 static int dw_spi_set_speed(struct udevice *bus, uint speed)
 {
        struct dw_spi_platdata *plat = dev_get_platdata(bus);
@@ -624,6 +727,7 @@ static int dw_spi_remove(struct udevice *bus)
 
 static const struct dm_spi_ops dw_spi_ops = {
        .xfer           = dw_spi_xfer,
+       .mem_ops        = &dw_spi_mem_ops,
        .set_speed      = dw_spi_set_speed,
        .set_mode       = dw_spi_set_mode,
        /*