Re: [PATCH v3 6/6] spi: cadence-xspi: Add workaround for old Marvell firmwares

[Jisheng Zhang <jszhang@kernel.org>]

On Thu, Nov 12, 2026 at 03:30:50PM +0100, Paul Cercueil wrote:
> From: Tanmay Jagdale <tanmay@marvell.com>
> 
> Older firmwares from Marvell used the cdns,xspi-nor compatible string
> for the Marvell-specific xSPI IP, which is incompatible.
> 
> Add a workaround to support this case, checking for a Marvell board in
> the DTB or the ACPI tables.

+ DT maintainers,

I want to query a rule here: does mainlined driver need to care
about out-of-tree dtb bug?

> 
> Signed-off-by: Tanmay Jagdale <tanmay@marvell.com>
> Co-developed-by: Paul Cercueil <paul.cercueil@bootlin.com>
> Signed-off-by: Paul Cercueil <paul.cercueil@bootlin.com>
> 
> ---
> 
> v2: Replace the workaround based on the presence of the "xfer" resource
>     with a mechanism that identifies a Marvell SoC based on the board's
>     compatible string on DTB, and the DSDT table on ACPI.
> 
> v3: Wrap ACPI specific code with CONFIG_ACPI guards, as some of the
>     functions and structs aren't defined without CONFIG_ACPI.
> ---
>  drivers/spi/spi-cadence-xspi.c | 41 +++++++++++++++++++++++++++++++++-
>  1 file changed, 40 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/spi/spi-cadence-xspi.c b/drivers/spi/spi-cadence-xspi.c
> index 8fa58a0412e3..7b06b95af794 100644
> --- a/drivers/spi/spi-cadence-xspi.c
> +++ b/drivers/spi/spi-cadence-xspi.c
> @@ -2,6 +2,7 @@
>  // Cadence XSPI flash controller driver
>  // Copyright (C) 2020-21 Cadence
>  
> +#include <linux/acpi.h>
>  #include <linux/completion.h>
>  #include <linux/delay.h>
>  #include <linux/err.h>
> @@ -11,11 +12,13 @@
>  #include <linux/iopoll.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
> +#include <linux/of.h>
>  #include <linux/platform_device.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/property.h>
>  #include <linux/spi/spi.h>
>  #include <linux/spi/spi-mem.h>
> +#include <linux/string.h>
>  #include <linux/bitfield.h>
>  #include <linux/limits.h>
>  #include <linux/log2.h>
> @@ -775,7 +778,6 @@ static void cdns_xspi_print_phy_config(struct cdns_xspi_dev *cdns_xspi)
>  		 readl(cdns_xspi->auxbase + CDNS_XSPI_CCP_PHY_DLL_SLAVE_CTRL));
>  }
>  
> -#ifdef CONFIG_64BIT
>  static struct cdns_xspi_driver_data marvell_driver_data = {
>  	.mrvl_hw_overlay = true,
>  	.dll_phy_ctrl = MARVELL_REGS_DLL_PHY_CTRL,
> @@ -788,6 +790,7 @@ static struct cdns_xspi_driver_data marvell_driver_data = {
>  	.rfile_phy_dll_slave_ctrl = MARVELL_RFILE_PHY_DLL_SLAVE_CTRL,
>  };
>  
> +#ifdef CONFIG_64BIT
>  static const int cdns_mrvl_xspi_clk_div_list[] = {
>  	4,	//0x0 = Divide by 4.   SPI clock is 200 MHz.
>  	6,	//0x1 = Divide by 6.   SPI clock is 133.33 MHz.
> @@ -1228,6 +1231,33 @@ static int cdns_xspi_transfer_one_message_b0(struct spi_controller *controller,
>  }
>  #endif
>  
> +#ifdef CONFIG_ACPI
> +static const struct acpi_platform_list mrvl_platform_list[] = {
> +	{
> +		.oem_id = "MRVL  ",
> +		.oem_table_id = "CN10K",
> +		.table = ACPI_SIG_DSDT,
> +		.pred = all_versions,
> +	},
> +	{ }
> +};
> +#endif
> +
> +static inline bool cdns_is_marvell(struct device *dev)
> +{
> +	const char *compatible;
> +
> +#ifdef CONFIG_ACPI
> +	if (has_acpi_companion(dev))
> +		return acpi_match_platform_list(mrvl_platform_list) >= 0;
> +#endif
> +
> +	if (of_machine_read_compatible(&compatible, 0) < 0)
> +		return false; /* shouldn't actually happen */
> +
> +	return strstarts(compatible, "marvell,");
> +}
> +
>  static int cdns_xspi_probe(struct platform_device *pdev)
>  {
>  	struct device *dev = &pdev->dev;
> @@ -1249,6 +1279,15 @@ static int cdns_xspi_probe(struct platform_device *pdev)
>  	if (!cdns_xspi->driver_data)
>  		return -ENODEV;
>  
> +	if (IS_ENABLED(CONFIG_64BIT) &&
> +	    !cdns_xspi->driver_data->mrvl_hw_overlay &&
> +	    cdns_is_marvell(dev)) {
> +		/* Some old firmwares use the base compatible string... */
> +
> +		dev_warn(dev, "Using the cdns,xspi-nor compatible string on a Marvell SoC. Please fix firmware!\n");
> +		cdns_xspi->driver_data = &marvell_driver_data;
> +	}
> +
>  	host->mem_ops = &cadence_xspi_mem_ops;
>  	cdns_xspi->sdma_handler = &cdns_xspi_sdma_handle;
>  	cdns_xspi->set_interrupts_handler = &cdns_xspi_set_interrupts;
> -- 
> 2.47.3
>