Re: [PATCH v3 2/3] mtd: spi-nor: cadence-quadspi: Disable the DAC for Intel LGM SoC

From: Vignesh Raghavendra
Date: Wed Oct 16 2019 - 04:33:08 EST




On 09/09/19 4:17 PM, Ramuthevar,Vadivel MuruganX wrote:
> From: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx>
>
> on Intel's Lightning Mountain(LGM) SoCs QSPI controller do not use

s/on/On

> Direct Access Controller(DAC).
>
> This patch introduces to properly disable the Direct Access Controller

"This patch adds a quirk to disable..." or something something similar

> for data transfer instead it uses indirect data transfer.
>
> Signed-off-by: Ramuthevar Vadivel Murugan <vadivel.muruganx.ramuthevar@xxxxxxxxxxxxxxx>
> ---
> drivers/mtd/spi-nor/Kconfig | 2 +-
> drivers/mtd/spi-nor/cadence-quadspi.c | 21 +++++++++++++++++++++
> 2 files changed, 22 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/spi-nor/Kconfig b/drivers/mtd/spi-nor/Kconfig
> index 6de83277ce8b..ba2e372ae514 100644
> --- a/drivers/mtd/spi-nor/Kconfig
> +++ b/drivers/mtd/spi-nor/Kconfig
> @@ -34,7 +34,7 @@ config SPI_ASPEED_SMC
>
> config SPI_CADENCE_QUADSPI
> tristate "Cadence Quad SPI controller"
> - depends on OF && (ARM || ARM64 || COMPILE_TEST)
> + depends on OF && (ARM || ARM64 || COMPILE_TEST || X86)
> help
> Enable support for the Cadence Quad SPI Flash controller.
>
> diff --git a/drivers/mtd/spi-nor/cadence-quadspi.c b/drivers/mtd/spi-nor/cadence-quadspi.c
> index 67f15a1f16fd..73b9fbd1508a 100644
> --- a/drivers/mtd/spi-nor/cadence-quadspi.c
> +++ b/drivers/mtd/spi-nor/cadence-quadspi.c
> @@ -33,6 +33,7 @@
>
> /* Quirks */
> #define CQSPI_NEEDS_WR_DELAY BIT(0)
> +#define CQSPI_DISABLE_DAC_MODE BIT(1)
>
> /* Capabilities mask */
> #define CQSPI_BASE_HWCAPS_MASK \
> @@ -609,6 +610,13 @@ static int cqspi_write_setup(struct spi_nor *nor)
> struct cqspi_st *cqspi = f_pdata->cqspi;
> void __iomem *reg_base = cqspi->iobase;
>
> + /* Disable direct access controller */
> + if (!f_pdata->use_direct_mode) {
> + reg = readl(reg_base + CQSPI_REG_CONFIG);
> + reg &= ~CQSPI_REG_CONFIG_ENB_DIR_ACC_CTRL;
> + writel(reg, reg_base + CQSPI_REG_CONFIG);
> + }
> +
> /* Set opcode. */
> reg = nor->program_opcode << CQSPI_REG_WR_INSTR_OPCODE_LSB;
> writel(reg, reg_base + CQSPI_REG_WR_INSTR);
> @@ -1328,6 +1336,7 @@ static int cqspi_probe(struct platform_device *pdev)
> struct resource *res_ahb;
> struct reset_control *rstc, *rstc_ocp;
> const struct cqspi_driver_platdata *ddata;
> + struct cqspi_flash_pdata *f_pdata;
> int ret;
> int irq;
>
> @@ -1436,6 +1445,9 @@ static int cqspi_probe(struct platform_device *pdev)
> goto probe_setup_failed;
> }
>
> + if (ddata && (ddata->quirks & CQSPI_DISABLE_DAC_MODE))
> + f_pdata->use_direct_mode = false;
> +

If you do this here, you will still end up acquiring a DMA channel in
cqspi_request_mmap_dma() (called from cqspi_setup_flash()). So, please
move the check to cqspi_setup_flash().

> return ret;
> probe_setup_failed:
> cqspi_controller_enable(cqspi, 0);
> @@ -1510,6 +1522,11 @@ static const struct cqspi_driver_platdata am654_ospi = {
> .quirks = CQSPI_NEEDS_WR_DELAY,
> };
>
> +static const struct cqspi_driver_platdata intel_lgm_qspi = {
> + .hwcaps_mask = CQSPI_BASE_HWCAPS_MASK,
> + .quirks = CQSPI_DISABLE_DAC_MODE,
> +};
> +
> static const struct of_device_id cqspi_dt_ids[] = {
> {
> .compatible = "cdns,qspi-nor",
> @@ -1523,6 +1540,10 @@ static const struct of_device_id cqspi_dt_ids[] = {
> .compatible = "ti,am654-ospi",
> .data = &am654_ospi,
> },
> + {
> + .compatible = "intel,lgm-qspi",
> + .data = &intel_lgm_qspi,
> + },
> { /* end of table */ }
> };
>
>

--
Regards
Vignesh