[PATCH v4 07/17] spi: dw: Add mem_ops
Rick Chen
rickchen36 at gmail.com
Tue Feb 18 09:34:29 CET 2020
Hi Sean
> The dw spi devices on the Kendryte K210 must be operated in a specific
> fasion which cannot be achived through multiple writes to via dw_spi_xfer
> (as it is currently written). This patch adds an implementation of exec_op,
> which gives correct behaviour when reading/writing spi flash.
>
> I would like to be able to modify the existing dw_spi_xfer function such
> that it works properly (e.g. with the mmc_spi driver). However, the only
> example code I have to work off is Kendryte's sdk (which is written in the
> exec_op style), and I do not have access to the datasheet (if anyone does,
> I would love to have a look!).
>
> Signed-off-by: Sean Anderson <seanga2 at gmail.com>
> ---
>
> Changes in v4:
> - New
>
> drivers/spi/designware_spi.c | 123 +++++++++++++++++++++++++++++++++--
> 1 file changed, 119 insertions(+), 4 deletions(-)
>
Patch 6 and 7 shall be applied via spi tree.
You mix them together, the patchwork will become complicated.
It will be better for me to wait for a period of time to get the
approval(Reviewed-by or Acked-by) of SPI MAINTAINER.
Thanks
Rick
> diff --git a/drivers/spi/designware_spi.c b/drivers/spi/designware_spi.c
> index 04cc873754..277eb19a0b 100644
> --- a/drivers/spi/designware_spi.c
> +++ b/drivers/spi/designware_spi.c
> @@ -17,6 +17,7 @@
> #include <errno.h>
> #include <malloc.h>
> #include <spi.h>
> +#include <spi-mem.h>
> #include <fdtdec.h>
> #include <reset.h>
> #include <linux/compat.h>
> @@ -107,8 +108,8 @@ struct dw_spi_priv {
> int len;
>
> u32 fifo_len; /* depth of the FIFO buffer */
> - void *tx;
> - void *tx_end;
> + const void *tx;
> + const void *tx_end;
> void *rx;
> void *rx_end;
>
> @@ -344,7 +345,7 @@ static void dw_writer(struct dw_spi_priv *priv)
> txw = *(u16 *)(priv->tx);
> }
> dw_write(priv, DW_SPI_DR, txw);
> - debug("%s: tx=0x%02x\n", __func__, txw);
> + log_io("tx=0x%02x\n", txw);
> priv->tx += priv->bits_per_word >> 3;
> }
> }
> @@ -356,7 +357,7 @@ static void dw_reader(struct dw_spi_priv *priv)
>
> while (max--) {
> rxw = dw_read(priv, DW_SPI_DR);
> - debug("%s: rx=0x%02x\n", __func__, rxw);
> + log_io("rx=0x%02x\n", rxw);
>
> /* Care about rx if the transfer's original "rx" is not null */
> if (priv->rx_end - priv->len) {
> @@ -483,6 +484,115 @@ static int dw_spi_xfer(struct udevice *dev, unsigned int bitlen,
> return ret;
> }
>
> +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_platdata *plat = dev_get_platdata(bus);
> + 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 = SPI_TMOD_EPROMREAD;
> + else
> + priv->tmode = SPI_TMOD_TO;
> +
> + debug("%s: buf=%p len=%u [bytes]\n",
> + __func__, op->data.buf.in, op->data.nbytes);
> +
> + cr0 = GEN_CTRL0(priv, plat);
> + debug("%s: cr0=%08x\n", __func__, cr0);
> +
> + spi_enable_chip(priv, 0);
> + dw_write(priv, DW_SPI_CTRL0, cr0);
> + if (read)
> + dw_write(priv, DW_SPI_CTRL1, op->data.nbytes - 1);
> + spi_enable_chip(priv, 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);
> +
> + priv->tx = &op_buf;
> + priv->tx_end = priv->tx + op_len;
> + 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.
> + *
> + * We heuristically break out of the loop when we stop getting data.
> + * This is to stop us from hanging if the device doesn't send any data
> + * (either at all, or after sending a response). For example, one flash
> + * chip I tested did not send anything back after the first 64K of data.
> + */
> + if (read) {
> + /* If we have gotten any data back yet */
> + bool got_data = false;
> + /* How many times we have looped without reading anything */
> + int loops_since_read = 0;
> + struct spi_mem_op *mut_op = (struct spi_mem_op *)op;
> +
> + 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) {
> + void *last_rx = priv->rx;
> +
> + dw_reader(priv);
> + if (priv->rx == last_rx) {
> + loops_since_read++;
> + /* Thresholds are arbitrary */
> + if (loops_since_read > 256)
> + break;
> + else if (got_data && loops_since_read > 32)
> + break;
> + } else {
> + got_data = true;
> + loops_since_read = 0;
> + }
> + }
> +
> + /* Update with the actual amount of data read */
> + mut_op->data.nbytes -= priv->rx_end - priv->rx;
> + } 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);
> + debug("%s: %u bytes xfered\n", __func__, op->data.nbytes);
> + return ret;
> +}
> +
> static int dw_spi_set_speed(struct udevice *bus, uint speed)
> {
> struct dw_spi_platdata *plat = dev_get_platdata(bus);
> @@ -546,8 +656,13 @@ static int dw_spi_remove(struct udevice *bus)
> return 0;
> }
>
> +static const struct spi_controller_mem_ops dw_spi_mem_ops = {
> + .exec_op = dw_spi_exec_op,
> +};
> +
> 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,
> /*
> --
> 2.25.0
>
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