Patch "spi: sh-msiof: Avoid invalid clock generator parameters" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

spi: sh-msiof: Avoid invalid clock generator parameters

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
spi-sh-msiof-avoid-invalid-clock-generator-parameters.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Geert Uytterhoeven <[email protected]>
Date: Fri, 5 Aug 2016 10:17:52 +0200
Subject: spi: sh-msiof: Avoid invalid clock generator parameters

From: Geert Uytterhoeven <[email protected]>

commit c3ccf357c3d75bd2924e049b6a991f7c0c111068 upstream.

The conversion from a look-up table to a calculation for clock generator parameters forgot to take into account that BRDV x 1/1 is valid only if BRPS is x 1/1 or x 1/2, leading to undefined behavior (e.g. arbitrary clock rates).

This limitation is documented for the MSIOF module in all supported SH/R-Mobile and R-Car Gen2/Gen3 ARM SoCs.

Tested on r8a7791/koelsch and r8a7795/salvator-x.

---
 drivers/spi/spi-sh-msiof.c |    3 +++
 1 file changed, 3 insertions(+)

@@ -263,6 +263,9 @@ static void sh_msiof_spi_set_clk_regs(st
 
 	for (k = 0; k < ARRAY_SIZE(sh_msiof_spi_div_table); k++) {
 		brps = DIV_ROUND_UP(div, sh_msiof_spi_div_table[k].div);
+		/* SCR_BRDV_DIV_1 is valid only if BRPS is x 1/1 or x 1/2 */
+		if (sh_msiof_spi_div_table[k].div == 1 && brps > 2)
+			continue;
 		if (brps <= 32) /* max of brdv is 32 */
 			break;
 	}

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/spi-sh-msiof-avoid-invalid-clock-generator-parameters.patch