Re: [PATCH 1/1] mtd/intel-spi: Support cmdline-based partition

[ron minnich <rminnich@gmail.com>]

On Mon, Mar 23, 2020 at 12:58 PM ron minnich <rminnich@gmail.com> wrote:
>
> The MTD subsystem can support command-line defined partitions
> for one or more MTD devices.
>
> The format is:
>  * mtdparts=<mtddef>[;<mtddef]
>  * <mtddef>  := <mtd-id>:<partdef>[,<partdef>]
>
> The ':' currently separates the id from the partdef.
>
> The mtdparts can define more than one part, in which case
> there will be more than one <mtd-id>:<partdef> component.
>
> On Intel spi devices, the name is set to the PCI slot name,
> e.g. 0000:00:1f.5.  There are two : in the name alone.
> Since strchr is used to find the <mtd-id>,
> in this case it will return the wrong
> result. Using strrchr is not an option, as there may
> be more than one mtddef in the argument.
>
> This change modifies the name attached to the intel spi
> device, changing all ':' to '.', e.g. 0000:00:1f.5
> becomes 0000.00.1f.5. It also adds command line partition
> parsing registration to the intel_spi_probe function.
>
> This change has been tested and works on a modern Intel chipset with
> a 64 MiB FLASH part.
>
> Signed-off-by: Ronald G. Minnich <rminnich@google.com>
> ---
>  drivers/mtd/spi-nor/intel-spi-pci.c | 22 ++++++++++++++++++++++
>  drivers/mtd/spi-nor/intel-spi.c     |  4 +++-
>  2 files changed, 25 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/spi-nor/intel-spi-pci.c
> b/drivers/mtd/spi-nor/intel-spi-pci.c
> index 81329f680bec..57716e53c219 100644
> --- a/drivers/mtd/spi-nor/intel-spi-pci.c
> +++ b/drivers/mtd/spi-nor/intel-spi-pci.c
> @@ -24,6 +24,23 @@ static const struct intel_spi_boardinfo cnl_info = {
>         .type = INTEL_SPI_CNL,
>  };
>
> +/*
> + * PCI names use a ':' as a separator, which conflicts
> + * with the mtdparts cmdline parameter. Dup the name and
> + * replace : with .
> + */
> +static int fixname(struct pci_dev *pdev) {
> +       char *name;
> +        name = kstrdup(pci_name(pdev), GFP_KERNEL);
> +       if (! name) {
> +               return -ENOMEM;
> +       }
> +       strreplace(name, ':', '.');
> +       dev_set_name(&pdev->dev, name);
> +       kfree(name);
> +       return 0;
> +}
> +
>  static int intel_spi_pci_probe(struct pci_dev *pdev,
>                                const struct pci_device_id *id)
>  {
> @@ -41,6 +58,11 @@ static int intel_spi_pci_probe(struct pci_dev *pdev,
>         if (!info)
>                 return -ENOMEM;
>
> +       if (fixname(pdev)) {
> +               kfree(info);
> +               return -ENOMEM;
> +       }
> +
>         /* Try to make the chip read/write */
>         pci_read_config_dword(pdev, BCR, &bcr);
>         if (!(bcr & BCR_WPD)) {
> diff --git a/drivers/mtd/spi-nor/intel-spi.c b/drivers/mtd/spi-nor/intel-spi.c
> index 61d2a0ad2131..261b10cf5076 100644
> --- a/drivers/mtd/spi-nor/intel-spi.c
> +++ b/drivers/mtd/spi-nor/intel-spi.c
> @@ -894,6 +894,8 @@ static const struct spi_nor_controller_ops
> intel_spi_controller_ops = {
>         .erase = intel_spi_erase,
>  };
>
> +static const char * const part_probes[] = { "cmdlinepart", NULL };
> +
>  struct intel_spi *intel_spi_probe(struct device *dev,
>         struct resource *mem, const struct intel_spi_boardinfo *info)
>  {
> @@ -941,7 +943,7 @@ struct intel_spi *intel_spi_probe(struct device *dev,
>         if (!ispi->writeable || !writeable)
>                 ispi->nor.mtd.flags &= ~MTD_WRITEABLE;
>
> -       ret = mtd_device_register(&ispi->nor.mtd, &part, 1);
> +       ret = mtd_device_parse_register(&ispi->nor.mtd, part_probes,
> NULL, &part, 1);
>         if (ret)
>                 return ERR_PTR(ret);
>
> --
> 2.25.1.696.g5e7596f4ac-goog

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