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    SubjectRe: [PATCH 04/10] spi: aspeed: Add support for direct mapping
    On 14/02/22 10:42AM, Cédric Le Goater wrote:
    > Use direct mapping to read the flash device contents. This operation
    > mode is called "Command mode" on Aspeed SoC SMC controllers. It uses a
    > Control Register for the settings to apply when a memory operation is
    > performed on the flash device mapping window.
    >
    > If the window is not big enough, fall back to the "User mode" to
    > perform the read.
    >
    > Direct mapping for writes will come later when validated.
    >
    > Signed-off-by: Cédric Le Goater <clg@kaod.org>
    > ---
    > drivers/spi/spi-aspeed-smc.c | 67 ++++++++++++++++++++++++++++++++++--
    > 1 file changed, 65 insertions(+), 2 deletions(-)
    >
    > diff --git a/drivers/spi/spi-aspeed-smc.c b/drivers/spi/spi-aspeed-smc.c
    > index 0aeff6f468af..8d33fcb7736a 100644
    > --- a/drivers/spi/spi-aspeed-smc.c
    > +++ b/drivers/spi/spi-aspeed-smc.c
    > @@ -345,8 +345,8 @@ static int do_aspeed_spi_exec_op(struct spi_mem *mem, const struct spi_mem_op *o
    > if (!op->addr.nbytes)
    > ret = aspeed_spi_read_reg(chip, op);
    > else
    > - ret = aspeed_spi_read_user(chip, op, op->addr.val,
    > - op->data.nbytes, op->data.buf.in);
    > + memcpy_fromio(op->data.buf.in, chip->ahb_base + op->addr.val,
    > + op->data.nbytes);

    Why change this? exec_op should be independent from dirmap APIs. And you
    don't even do the ahb_window_size checks here.

    > } else {
    > if (!op->addr.nbytes)
    > ret = aspeed_spi_write_reg(chip, op);
    > @@ -426,10 +426,73 @@ static int aspeed_spi_chip_set_default_window(struct aspeed_spi_chip *chip)
    > return chip->ahb_window_size ? 0 : -1;
    > }
    >
    > +static int aspeed_spi_dirmap_create(struct spi_mem_dirmap_desc *desc)
    > +{
    > + struct aspeed_spi *aspi = spi_controller_get_devdata(desc->mem->spi->master);
    > + struct aspeed_spi_chip *chip = &aspi->chips[desc->mem->spi->chip_select];
    > + struct spi_mem_op *op = &desc->info.op_tmpl;
    > + u32 ctl_val;
    > + int ret = 0;
    > +
    > + chip->clk_freq = desc->mem->spi->max_speed_hz;
    > +
    > + /* Only for reads */
    > + if (op->data.dir != SPI_MEM_DATA_IN)
    > + return -EOPNOTSUPP;
    > +
    > + if (desc->info.length > chip->ahb_window_size)
    > + dev_warn(aspi->dev, "CE%d window (%dMB) too small for mapping",
    > + chip->cs, chip->ahb_window_size >> 20);
    > +
    > + /* Define the default IO read settings */
    > + ctl_val = readl(chip->ctl) & ~CTRL_IO_CMD_MASK;
    > + ctl_val |= aspeed_spi_get_io_mode(op) |
    > + op->cmd.opcode << CTRL_COMMAND_SHIFT |
    > + CTRL_IO_DUMMY_SET(op->dummy.nbytes / op->dummy.buswidth) |
    > + CTRL_IO_MODE_READ;
    > +
    > + /* Tune 4BYTE address mode */
    > + if (op->addr.nbytes) {
    > + u32 addr_mode = readl(aspi->regs + CE_CTRL_REG);
    > +
    > + if (op->addr.nbytes == 4)
    > + addr_mode |= (0x11 << chip->cs);
    > + else
    > + addr_mode &= ~(0x11 << chip->cs);
    > + writel(addr_mode, aspi->regs + CE_CTRL_REG);
    > + }
    > +
    > + /* READ mode is the controller default setting */
    > + chip->ctl_val[ASPEED_SPI_READ] = ctl_val;
    > + writel(chip->ctl_val[ASPEED_SPI_READ], chip->ctl);
    > +
    > + dev_info(aspi->dev, "CE%d read buswidth:%d [0x%08x]\n",
    > + chip->cs, op->data.buswidth, chip->ctl_val[ASPEED_SPI_READ]);
    > +
    > + return ret;
    > +}
    > +
    > +static int aspeed_spi_dirmap_read(struct spi_mem_dirmap_desc *desc,
    > + u64 offset, size_t len, void *buf)
    > +{
    > + struct aspeed_spi *aspi = spi_controller_get_devdata(desc->mem->spi->master);
    > + struct aspeed_spi_chip *chip = &aspi->chips[desc->mem->spi->chip_select];
    > +
    > + /* Switch to USER command mode if mapping window is too small */
    > + if (chip->ahb_window_size < offset + len)
    > + aspeed_spi_read_user(chip, &desc->info.op_tmpl, offset, len, buf);
    > + else
    > + memcpy_fromio(buf, chip->ahb_base + offset, len);
    > +
    > + return len;
    > +}
    > +
    > static const struct spi_controller_mem_ops aspeed_spi_mem_ops = {
    > .supports_op = aspeed_spi_supports_op,
    > .exec_op = aspeed_spi_exec_op,
    > .get_name = aspeed_spi_get_name,
    > + .dirmap_create = aspeed_spi_dirmap_create,
    > + .dirmap_read = aspeed_spi_dirmap_read,
    > };
    >
    > static void aspeed_spi_chip_set_type(struct aspeed_spi_chip *chip, int type)
    > --
    > 2.34.1
    >

    --
    Regards,
    Pratyush Yadav
    Texas Instruments Inc.

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