On Thu, Mar 01, 2018 at 11:20:11AM +0100, Geert Uytterhoeven wrote: > Hi Simon, > > On Fri, Feb 23, 2018 at 9:14 AM, Simon Horman <horms@xxxxxxxxxxxx> wrote: > > On Thu, Feb 22, 2018 at 09:38:39AM +0100, Geert Uytterhoeven wrote: > >> On Wed, Feb 21, 2018 at 7:32 PM, Simon Horman <horms@xxxxxxxxxxxx> wrote: > >> > On Wed, Feb 21, 2018 at 05:30:12PM +0100, Geert Uytterhoeven wrote: > >> >> On Wed, Feb 21, 2018 at 5:13 PM, Simon Horman <horms@xxxxxxxxxxxx> wrote: > >> >> > On Tue, Feb 20, 2018 at 01:51:28PM +0100, Geert Uytterhoeven wrote: > >> >> >> On Mon, Feb 12, 2018 at 6:44 PM, Fabrizio Castro > >> >> >> <fabrizio.castro@xxxxxxxxxxxxxx> wrote: > >> >> >> > this series has been around for some time as RFC, and it has collected > >> >> >> > useful comments from the community along the way. > >> >> >> > The solution proposed by this patch set works for most R-Car Gen2 and > >> >> >> > RZ/G1 devices, but not all of them. We now know that for some R-Car > >> >> >> > Gen2 early revisions there is no proper software fix. Anyway, no > >> >> >> > product has been built around early revisions, but development boards > >> >> >> > mounting early revisions (basically prototypes) are still out there. > >> >> >> > As a result, this series isn't enabling the internal watchdog on R-Car > >> >> >> > Gen2 boards, developers may enable it in board specific device trees > >> >> >> > if needed. > >> >> >> > This series has been tested by me on the iwg20d, iwg22d, Lager, Alt, > >> >> >> > and Koelsch boards. > >> >> >> > > >> >> >> > The problem > >> >> >> > =========== > >> >> >> > To deal with SMP on R-Car Gen2 and RZ/G1, we install a reset vector > >> >> >> > to ICRAM1 and we program the [S]BAR registers so that when we turn ON > >> >> >> > the non-boot CPUs they are redirected to the reset vector installed by > >> >> >> > Linux in ICRAM1, and eventually they continue the execution to RAM, > >> >> >> > where the SMP bring-up code will take care of the rest. > >> >> >> > The content of the [S]BAR registers survives a watchdog triggered reset, > >> >> >> > and as such after the watchdog fires the boot core will try and execute > >> >> >> > the SMP bring-up code instead of jumping to the bootrom code. > >> >> >> > > >> >> >> > The fix > >> >> >> > ======= > >> >> >> > The main strategy for the solution is to let the reset vector decide > >> >> >> > if it needs to jump to shmobile_boot_fn or to the bootrom code. > >> >> >> > In a watchdog triggered reset scenario, since the [S]BAR registers keep > >> >> >> > their values, the boot CPU will jump into the newly designed reset > >> >> >> > vector, the assembly routine will eventually test WOVF (a bit in register > >> >> >> > RWTCSRA that indicates if the watchdog counter has overflown, the value > >> >> >> > of this bit gets retained in this scenario), and jump to the bootrom code > >> >> >> > which will in turn load up the bootloader, etc. > >> >> >> > When bringing up SMP or using CPU hotplug, the reset vector will jump > >> >> >> > to shmobile_boot_fn instead. > >> >> >> > > >> >> >> > Thank you All for your help. > >> >> >> > > >> >> >> > Best regards, > >> >> >> > > >> >> >> > Fabrizio Castro (26): > >> >> >> > ARM: shmobile: Add watchdog support > >> >> >> > ARM: dts: r8a7743: Adjust SMP routine size > >> >> >> > ARM: dts: r8a7745: Adjust SMP routine size > >> >> >> > ARM: dts: r8a7790: Adjust SMP routine size > >> >> >> > ARM: dts: r8a7791: Adjust SMP routine size > >> >> >> > ARM: dts: r8a7792: Adjust SMP routine size > >> >> >> > ARM: dts: r8a7793: Adjust SMP routine size > >> >> >> > ARM: dts: r8a7794: Adjust SMP routine size > >> >> >> > soc: renesas: rcar-rst: Enable watchdog as reset trigger for Gen2 > >> >> >> > ARM: shmobile: rcar-gen2: Add watchdog support > >> >> >> > dt-bindings: watchdog: renesas-wdt: Add R-Car Gen2 support > >> >> >> > watchdog: renesas_wdt: Add R-Car Gen2 support > >> >> >> > watchdog: renesas_wdt: Add restart handler > >> >> >> > ARM: shmobile: defconfig: Enable RENESAS_WDT_GEN > >> >> >> > clk: renesas: r8a7743: Add rwdt clock > >> >> >> > clk: renesas: r8a7745: Add rwdt clock > >> >> >> > clk: renesas: r8a7790: Add rwdt clock > >> >> >> > clk: renesas: r8a7791/r8a7793: Add rwdt clock > >> >> >> > clk: renesas: r8a7794: Add rwdt clock > >> >> >> > ARM: dts: r8a7743: Add watchdog support to SoC dtsi > >> >> >> > ARM: dts: r8a7745: Add watchdog support to SoC dtsi > >> >> >> > ARM: dts: r8a7790: Add watchdog support to SoC dtsi > >> >> >> > ARM: dts: r8a7791: Add watchdog support to SoC dtsi > >> >> >> > ARM: dts: r8a7794: Add watchdog support to SoC dtsi > >> >> >> > ARM: dts: iwg20m: Add watchdog support to SoM dtsi > >> >> >> > ARM: dts: iwg22m: Add watchdog support to SoM dtsi > >> >> >> > > >> >> >> > .../devicetree/bindings/watchdog/renesas-wdt.txt | 19 ++++++-- > >> >> >> > arch/arm/boot/dts/r8a7743-iwg20m.dtsi | 5 ++ > >> >> >> > arch/arm/boot/dts/r8a7743.dtsi | 12 ++++- > >> >> >> > arch/arm/boot/dts/r8a7745-iwg22m.dtsi | 5 ++ > >> >> >> > arch/arm/boot/dts/r8a7745.dtsi | 12 ++++- > >> >> >> > arch/arm/boot/dts/r8a7790.dtsi | 12 ++++- > >> >> >> > arch/arm/boot/dts/r8a7791.dtsi | 12 ++++- > >> >> >> > arch/arm/boot/dts/r8a7792.dtsi | 2 +- > >> >> >> > arch/arm/boot/dts/r8a7793.dtsi | 2 +- > >> >> >> > arch/arm/boot/dts/r8a7794.dtsi | 12 ++++- > >> >> >> > arch/arm/configs/shmobile_defconfig | 1 + > >> >> >> > arch/arm/mach-shmobile/common.h | 6 +++ > >> >> >> > arch/arm/mach-shmobile/headsmp.S | 55 ++++++++++++++++++++++ > >> >> >> > arch/arm/mach-shmobile/platsmp-apmu.c | 1 + > >> >> >> > arch/arm/mach-shmobile/pm-rcar-gen2.c | 15 ++++-- > >> >> >> > drivers/clk/renesas/r8a7743-cpg-mssr.c | 2 + > >> >> >> > drivers/clk/renesas/r8a7745-cpg-mssr.c | 2 + > >> >> >> > drivers/clk/renesas/r8a7790-cpg-mssr.c | 2 + > >> >> >> > drivers/clk/renesas/r8a7791-cpg-mssr.c | 2 + > >> >> >> > drivers/clk/renesas/r8a7794-cpg-mssr.c | 2 + > >> >> >> > drivers/soc/renesas/rcar-rst.c | 35 +++++++++++--- > >> >> >> > drivers/watchdog/renesas_wdt.c | 39 +++++++++++++-- > >> >> >> > >> >> >> Thanks, I've queued the clock patches in clk-renesas-for-v4.17, as they are > >> >> >> a hard dependency for: > >> >> >> (1) The new reset vector in arch/arm/mach-shmobile/ > >> >> >> (2) The watchdog driver. > >> >> >> > >> >> >> Note that the watchdog driver itself (2) has a hard dependency on the > >> >> >> new reset vector (1). > >> >> > > >> >> > Thanks, I have marked the watchdog driver patch as Deferred. > >> >> > Please resubmit or otherwise ping me once they dependencies > >> >> > are in an rc release. > >> >> > >> >> I gave the dependencies a bit more thought. > >> >> > >> >> I think we can gain once release cycle if you would postpone the DTS patches > >> >> (both SMP routine size adjustments and RWDT device node additions) to v4.18. > >> >> Then all other parts can be upstreamed in parallel in v4.17, as nothing > >> >> will be activated before the DTS parts are in. > >> >> > >> >> Does this look sane? > >> > > >> > What about new DTS on old kernels of a specific vintage? > >> > >> New DTS would work fine on v4.16 and older, which don't have any of the > >> other patches from this series. > >> New DTS would work fine on v4.17, assumed all other patches from this > >> series get into v4.17. > >> > >> The only issue would be a new DTS on a kernel that has some but not all > >> other patches from this series. > > > > Thanks for the analysis. I think this is the key point. What is the risk of > > that happening? > > I think the risk is fairly low. > You control when the DTS changes go in, and also when they are backported > to LTSI. > > >> If we want to fast-track everything into v4.17, we need a stable branch, to be > >> pulled by all 5 actors (clk-renesas, mach-shmobile, soc-renesas, watchdog, > >> renesas-dts). > > > > It seems that watchdog is the only item on that list that neither you nor I > > sign off on. So I conclude that if the watchdog patch goes in early enough > > in the cycle then we ought to be in good shape. > > > > None the less, is it worth the risk? > > Do we want the functionality early, or can we wait until v4.19? I understand that the watchdog driver has been accepted and that as things currently stand if it is enabled in the build it will be enabled in DT and a crash will result. From my POV that is a regression so I have decided to adopt the alternate plan proposed by Geert above: in short drop DT patches (to avoid enabling broken driver) and enqueue mach-shmobile patches (which don't make things any worse. Patch-by-patch things are as follows. Dropped from "[PATCH v5 00/26] Fix watchdog on Renesas R-Car Gen2 and RZ/G1": 979d28f29742 ARM: dts: r8a7743: Adjust SMP routine size 0b205f679f5d ARM: dts: r8a7745: Adjust SMP routine size 2ad21a1d78b3 ARM: dts: r8a7790: Adjust SMP routine size 82c978459c77 ARM: dts: r8a7791: Adjust SMP routine size d303698e6ff3 ARM: dts: r8a7792: Adjust SMP routine size d8b8b9a1e295 ARM: dts: r8a7793: Adjust SMP routine size 70b3ab369773 ARM: dts: r8a7794: Adjust SMP routine size ebf26cf1b1de ARM: dts: r8a7743: Add watchdog support to SoC dtsi 5a4566ab3777 ARM: dts: r8a7745: Add watchdog support to SoC dtsi acd58e2bb1e5 ARM: dts: r8a7790: Add watchdog support to SoC dtsi e3f89168e72f ARM: dts: r8a7791: Add watchdog support to SoC dtsi e76a6a69a1fc ARM: dts: r8a7794: Add watchdog support to SoC dtsi 242cc1ab7f7c ARM: dts: iwg20m: Add watchdog support to SoM dtsi 748ed07f6c7c ARM: dts: iwg22m: Add watchdog support to SoM dtsi Dropped from "[PATCH/RFC 00/11] ARM: dts: rcar-gen2: Enable watchdog support": c257202482e2 ARM: dts: r8a7792: Add RWDT node 01ec04dec8eb ARM: dts: r8a7793: Add RWDT node 8e6ebe4f2f94 ARM: dts: lager: Enable watchdog support f223ad0198f6 ARM: dts: koelsch: Enable watchdog support 1d14d2bb700d ARM: dts: porter: Enable watchdog support bf71652fc955 ARM: dts: blanche: Enable watchdog support 13a0b10aeea4 ARM: dts: wheat: Enable watchdog support 4e247bf110b8 ARM: dts: gose: Enable watchdog support 2dcbd24bbf5e ARM: dts: alt: Enable watchdog support 7f6844c900b4 ARM: dts: silk: Enable watchdog support And applied: [v5] ARM: shmobile: rcar-gen2: Add watchdog support [v5] ARM: shmobile: Add watchdog support In the case of the last patch above I removed the #ifdef from the header file.
