Re: [PATCH v2 1/2] spi: fsl-spi: Fix parameter ram offset setup for CPM1

Le 03/10/2014 22:29, Scott Wood a écrit :

On Fri, 2014-10-03 at 18:49 +0200, Christophe Leroy wrote:

quoted

On CPM1, the SPI parameter RAM has a default location. In fsl_spi_cpm_get_pram()
there was a confusion between the SPI_BASE register and the base of the SPI
parameter RAM. Fortunatly, it was working properly with MPC866 and MPC885
because they do set SPI_BASE, but on MPC860 and other old MPC8xx that doesn't
set SPI_BASE, pram_ofs was not properly set. This patch fixes this confusion.

Signed-off-by: Christophe Leroy <redacted>

---
Changes from v1 to v2: none

  drivers/spi/spi-fsl-cpm.c | 9 ++++-----
  1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/spi/spi-fsl-cpm.c b/drivers/spi/spi-fsl-cpm.c
index 54b0637..0f3a912 100644
--- a/drivers/spi/spi-fsl-cpm.c
+++ b/drivers/spi/spi-fsl-cpm.c

@@ -262,15 +262,14 @@ static unsigned long fsl_spi_cpm_get_pram(struct mpc8xxx_spi *mspi)
  		pram_ofs = cpm_muram_alloc(SPI_PRAM_SIZE, 64);
  		out_be16(spi_base, pram_ofs);
  	} else {
-		struct spi_pram __iomem *pram = spi_base;
-		u16 rpbase = in_be16(&pram->rpbase);
+		u16 rpbase = in_be16(spi_base);
  
-		/* Microcode relocation patch applied? */
+		/* Microcode relocation patch applied | rpbase set by default */
  		if (rpbase) {
  			pram_ofs = rpbase;
  		} else {
-			pram_ofs = cpm_muram_alloc(SPI_PRAM_SIZE, 64);
-			out_be16(spi_base, pram_ofs);
+			pram_ofs = offsetof(cpm8xx_t, cp_dparam[PROFF_SPI]) -
+				   offsetof(cpm8xx_t, cp_dpmem[0]);
  		}
  	}

Why is PROFF_SPI not coming from the device tree?

That's where it starts to become tricky.

PROFF_SPI is defined in cpm1.h which is included by the driver already. It provides the default offset from the start of the parameter RAM.
Previously I had the following in my device tree, and the last part of the source above (the one for rpbase == 0) could not work.

            spi: spi@a80 {
                cell-index = <0>;
                compatible = "fsl,spi", "fsl,cpm1-spi";
                reg = <0xa80 0x30 0x3d80 0x30>;

First reg area was the area for SPI registers. Second area was the parameter RAM zone, which was just mapped to get access to the SPI_BASE pointer (rpbase)

Now I have

                compatible = "fsl,spi", "fsl,cpm1-spi-reloc";
                reg = <0xa80 0x30 0x3dac 0x2>;

First reg area is the area for SPI registers. Second area is the SPI_BASE, as for the CPM2.

On recent 8xx (885 and 866 at least) it contains the offset (=0x1D80) of the parameter RAM. But on old ones (860, ...) it contains 0. Therefore we have to get the default index in another way.
What I wanted was to keep something similar to what's done with CPM2.

What should it look like if that offset had to be in the device tree ?

Why don't I see any
cpm spi in any device tree nor any binding for it?

There's one in mgcoge.dts:

            spi@11aa0 {
                cell-index = <0>;
                compatible = "fsl,spi", "fsl,cpm2-spi";
                reg = <0x11a80 0x40 0x89fc 0x2>;

Christophe

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