Hello, This is the second version of the patches implementing suspend to RAM for the Marvell Armada XP platform, and specifically for the Armada XP GP board. If possible, I'd like this patch series to be considered as 3.19 material. For now, it does not implement suspend/resume for all device drivers, it only implements the core of the suspend/resume functionality: enough to make sure that the system can enter suspend and resume from suspend, restart all CPUs, and get back to a shell prompt. Additional work in individual device drivers will be needed, and provided as follow-up patches. There are three important things to understand about the hardware before reading this patch series: - The Armada XP SoC cannot put itself into a suspend to RAM state. It requires an external circuit, which in most cases, is a PIC micro-controller, to turn off the SoC. This PIC is connected to the SoC using a set of GPIOs, which allow the SoC to talk to the PIC and request certain things to be done. This means that the Armada XP suspend/resume logic has some board-specific code, which is fairly uncommon for suspend/resume code in the ARM world. We have chosen to represent the PIC and the fact that it's connected to the SoC using 3 GPIOs in the Device Tree. - When exiting from suspend, the SoC is actually powered up again completely from scratch, so it goes through the bootloader. The kernel has to fill a bootloader-specific structure at a fixed physical address to pass information to the bootloader that will tell the bootloader to do a resume and therefore jump back directly into the kernel resume entry point, instead of doing a normal boot. - The bootloader has to reconfigure the DRAM controller, which involves executing some DDR3 training code that has the unfortunate side effect of overwriting the first 10 KB of each DRAM chip-select. We therefore have to ensure that the kernel does not use the first 10 KB of each DRAM chip select. So, in sequence: * PATCH 1 and 2 are mainly preparation patches: Device Tree binding documentation, fixing an errata of the Armada XP. * PATCH 3 to 8 add suspend/resume support to some core drivers: irqchip, clocksource, gpio, mvebu-mbus and clock. Note that the gpio suspend/resume patch was said to be applied by Linus Walleij in http://lists.infradead.org/pipermail/linux-arm-kernel/2014-November/299201.html, but I don't see it present in https://git.kernel.org/cgit/linux/kernel/git/linusw/linux-gpio.git/log/?h=for-next, so I've kept it for now in this patch series. * PATCH 9 implements the core of the SoC suspend/resume logic. * PATCH 10 makes sure the first 10 KB of each DRAM chip select isn't used by the kernel. * PATCH 11 implements the board-specific suspend/resume logic, especially talking with the PIC micro-controller over GPIOs. * PATCH 12 and 13 make some other additional changes to the Armada XP SoC support to make suspend/resume work properly. * PATCH 14 to 16 modify the Armada XP and Armada XP GP Device Tree description to add the relevant hardware blocks that are needed for suspend/resume: description of the PIC micro-controller and the 3 GPIOs connecting it to the SoC, an additional set of the register for mvebu-mbus, and the registers for the SDRAM controller. Changes since v1: - Add Reviewed-by from Grégory Clement on Documentation: dt-bindings: minimal documentation for MVEBU SDRAM controller gpio: mvebu: add suspend/resume support bus: mvebu-mbus: provide a mechanism to save SDRAM window configuration - Added Acked-by from Grégory Clement on ARM: mvebu: enable strex backoff delay ARM: mvebu: reserve the first 10 KB of each memory bank for suspend/resume ARM: mvebu: make sure MMU is disabled in armada_370_xp_cpu_resume ARM: mvebu: synchronize secondary CPU clocks on resume ARM: mvebu: add suspend/resume DT information for Armada XP GP ARM: mvebu: adjust mbus controller description on Armada 370/XP ARM: mvebu: add SDRAM controller description for Armada XP clk: mvebu: add suspend/resume for gatable clocks - Add Acked-by from Alexandre Courbot on gpio: mvebu: add suspend/resume support - Drop patch "irqchip: irq-armada-370-xp: use proper return value for ->set_affinity()" as it was applied by Jason Cooper. - Fix typo in commit log of "clocksource: time-armada-370-xp: add suspend/resume support", noticed by Grégory Clement. - Adjust the name of the new variables used in "clocksource: time-armada-370-xp: add suspend/resume support" to save the state of timer 0, to make it clear only the state of timer 0 is preserved. Suggested by Grégory Clement. - In the suspend/resume code of the mvebu-mbus driver, make sure to fail (and therefore abort the suspend) if the MBus bridge registers were not mapped, instead of continuing with the suspend procedure and later on have a system that we know cannot resume properly. Suggested by Grégory Clement. - Remove cpu_pm_cluster_{enter,exit} calls from mach-mvebu/pm.c. Suggested by Grégory Clement. - In patch "ARM: mvebu: Armada XP GP specific suspend/resume code", fixup the wait loop of 100 cycles before entering suspend to actually initialize the r1 register before entering the wait loop. Before that, r1 was uninitialized, and a JTAG has shown that it was generally defined to 0, so the loop started by decrementing it by 1, making r1 equal 0xFFFFFFFF. So we had 2^32 iterations of a two instructions loop, at 1.2 Ghz, about a 7 seconds delay. Switching to the 100 cycles loop that is needed showed that the previous mdelay of 250 ms was way too short: the PIC needs several seconds before the two GPIO toggles. The Marvell vendor kernel uses a bit more than 3 seconds delay, and experience has shown that a 3 seconds delay works fine, while shorter delays sometimes lead to a system that doesn't enter suspend. Noticed by Grégory Clement. Best regards, Thomas Nadav Haklai (1): ARM: mvebu: enable strex backoff delay Thomas Petazzoni (15): Documentation: dt-bindings: minimal documentation for MVEBU SDRAM controller irqchip: irq-armada-370-xp: suspend/resume support clocksource: time-armada-370-xp: add suspend/resume support gpio: mvebu: add suspend/resume support bus: mvebu-mbus: suspend/resume support bus: mvebu-mbus: provide a mechanism to save SDRAM window configuration clk: mvebu: add suspend/resume for gatable clocks ARM: mvebu: implement suspend/resume support for Armada XP ARM: mvebu: reserve the first 10 KB of each memory bank for suspend/resume ARM: mvebu: Armada XP GP specific suspend/resume code ARM: mvebu: make sure MMU is disabled in armada_370_xp_cpu_resume ARM: mvebu: synchronize secondary CPU clocks on resume ARM: mvebu: add suspend/resume DT information for Armada XP GP ARM: mvebu: adjust mbus controller description on Armada 370/XP ARM: mvebu: add SDRAM controller description for Armada XP .../devicetree/bindings/bus/mvebu-mbus.txt | 17 +- .../memory-controllers/mvebu-sdram-controller.txt | 21 ++ arch/arm/boot/dts/armada-370-xp.dtsi | 3 +- arch/arm/boot/dts/armada-xp-gp.dts | 19 +- arch/arm/boot/dts/armada-xp.dtsi | 5 + arch/arm/mach-mvebu/Makefile | 2 +- arch/arm/mach-mvebu/board-v7.c | 51 +++++ arch/arm/mach-mvebu/common.h | 2 + arch/arm/mach-mvebu/platsmp.c | 31 ++- arch/arm/mach-mvebu/pm-board.c | 141 +++++++++++++ arch/arm/mach-mvebu/pm.c | 218 +++++++++++++++++++++ arch/arm/mach-mvebu/pmsu.h | 1 + arch/arm/mach-mvebu/pmsu_ll.S | 8 + arch/arm/mm/proc-v7.S | 2 - drivers/bus/mvebu-mbus.c | 180 ++++++++++++++++- drivers/clk/mvebu/common.c | 30 ++- drivers/clocksource/time-armada-370-xp.c | 25 +++ drivers/gpio/gpio-mvebu.c | 99 ++++++++++ drivers/irqchip/irq-armada-370-xp.c | 52 +++++ include/linux/mbus.h | 1 + 20 files changed, 874 insertions(+), 34 deletions(-) create mode 100644 Documentation/devicetree/bindings/memory-controllers/mvebu-sdram-controller.txt create mode 100644 arch/arm/mach-mvebu/pm-board.c create mode 100644 arch/arm/mach-mvebu/pm.c -- 2.1.0 -- 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
