From: Martin Sperl <kernel@xxxxxxxxxxxxxxxx> Add a sdram driver for the bcm2835 SOC. This is needed (especially) as there are 2 clocks that are needed by the SDram related HW block, which - right now are not claimed. Without this driver there is a possibility that one of these clocks (sdram (for low-voltage modes) or pll_core) or one of their parents does get disabled when the clocks or PLLs are actually needed. In the current form of this driver there is still no absolute certainty that such a situation can not happen under all cirumstances, but it reduces the likleyhood that this happens. To avoid this situation a patch-set will be needed that moves bcm2835-clk and bcm2835-sdram to earlier stages during the boot process. The driver also claims the 3 necessary register ranges to fully control the sdram (SDRAM, APHY, DPHY). But for some reasons these registers are not accessible and read as 0. It is still unclear if this is a general feature of the SOC or if this is configured by the binary-blob firmware. That is why this patchset includes an optional patch (patch 6: memory: bcm2835: expose register ranges via debugfs) that exposes these register sets via debugfs. Martin Sperl (6): dt: bindings: add bcm2835-memory-controller documentation memory: bcm2835: add bcm2835-memory controller ARM: dts: bcm2835: add the bcm2835-sdram-controller to the dt ARM: bcm2835_defconfig: add bcm2835-sdram controller ARM: multi_v7_defconfig: bcm2835: add bcm2835-sdram driver memory: bcm2835: expose register ranges via debugfs .../memory-controllers/brcm,bcm2835-sdram.txt | 30 ++ arch/arm/boot/dts/bcm283x.dtsi | 11 + arch/arm/configs/bcm2835_defconfig | 1 + arch/arm/configs/multi_v7_defconfig | 1 + drivers/memory/Kconfig | 7 + drivers/memory/Makefile | 1 + drivers/memory/bcm2835-sdram.c | 464 +++++++++++++++++++++ 7 files changed, 515 insertions(+) create mode 100644 Documentation/devicetree/bindings/memory-controllers/brcm,bcm2835-sdram.txt create mode 100644 drivers/memory/bcm2835-sdram.c -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
