Re: [PATCH v2 2/2] spi: fsl-spi: Allow dynamic allocation of CPM1 parameter RAM

From: Scott Wood
Date: Fri Oct 03 2014 - 15:52:01 EST


On Fri, 2014-10-03 at 18:49 +0200, Christophe Leroy wrote:
> On CPM1, the SPI parameter RAM has a default location. In order to use SPI while
> using SCC2 with features like QMC or Ethernet, it is necessary to relocate SPI
> parameter RAM in a free location in the CPM dual port RAM.

Please explain in more detail why it's necessary.

> With this patch,
> when "fsl,cpm1-spi-reloc" instead of "fsl,cpm1-spi" compatible is set in the
> device tree, the parameter RAM for SPI is dynamically allocated
> with cpm_muram_alloc().
>
> Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>
>
> ---
> Changes from v1 to v2: using OF compatible instead of compile time option
>
> drivers/spi/spi-fsl-cpm.c | 3 +++
> drivers/spi/spi-fsl-lib.c | 2 ++
> include/linux/fsl_devices.h | 1 +
> 3 files changed, 6 insertions(+)
>
> diff --git a/drivers/spi/spi-fsl-cpm.c b/drivers/spi/spi-fsl-cpm.c
> index 0f3a912..048ca5f 100644
> --- a/drivers/spi/spi-fsl-cpm.c
> +++ b/drivers/spi/spi-fsl-cpm.c
> @@ -261,6 +261,9 @@ static unsigned long fsl_spi_cpm_get_pram(struct mpc8xxx_spi *mspi)
> if (mspi->flags & SPI_CPM2) {
> pram_ofs = cpm_muram_alloc(SPI_PRAM_SIZE, 64);
> out_be16(spi_base, pram_ofs);
> + } else if (mspi->flags & SPI_CPM1_RELOC) {
> + pram_ofs = cpm_muram_alloc(SPI_PRAM_SIZE, 32);
> + out_be16(spi_base, pram_ofs);
> } else {
> u16 rpbase = in_be16(spi_base);
>
> diff --git a/drivers/spi/spi-fsl-lib.c b/drivers/spi/spi-fsl-lib.c
> index c3f7802..e9db4c5 100644
> --- a/drivers/spi/spi-fsl-lib.c
> +++ b/drivers/spi/spi-fsl-lib.c
> @@ -227,6 +227,8 @@ int of_mpc8xxx_spi_probe(struct platform_device *ofdev)
> pdata->flags = SPI_CPM_MODE | SPI_CPM2;
> else if (of_device_is_compatible(np, "fsl,cpm1-spi"))
> pdata->flags = SPI_CPM_MODE | SPI_CPM1;
> + else if (of_device_is_compatible(np, "fsl,cpm1-spi-reloc"))
> + pdata->flags = SPI_CPM_MODE | SPI_CPM1 | SPI_CPM1_RELOC;

Where's the binding and device tree update for this? What specific
aspect of hardware does it describe?

-Scott


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