On Mon, Dec 05, 2016 at 11:39:36AM +0100, Geert Uytterhoeven wrote: > Hi Simon, Magnus, > > This patch series allows booting secondary CPU cores on R-Car Gen2 when > hardware debug mode is enabled. In this mode, reset requests derived > from power-shutoff to the AP-system CPU cores must be enabled before the > AP-system CPU cores resume from power-shutoff for the first time. > Else resume may fail, causing the system to hang during boot. > Currently we avoid the hang by prohibiting booting secondary CPU cores > when hardware debug mode is enabled (except on legacy r8a7790, see > below). > > On all R-Car Gen2 SoCs, hardware debug mode is enabled by setting > MD21=1. On both Koelsch and Lager, this is done by setting mode switch > SW8-4 to OFF. > > Unfortunately the hang is not easy to reproduce: I only saw it (on > Koelsch) during real cold boot (power off during the night), and even > then it's not guaranteed to trigger. Pressing the reset button > afterwards recovers the system, and a subsequent boot will succeed > (incl. secondary CPU core boot). > > This series configures the reset requests as documented in the R-Car > Gen2 datasheet, and removes the check for MD21 during secondary CPU > bringup. It was inspired by CPU-specific patches in the BSP by > Nakamura-san. > > And finally, we get rid of reading the Mode Monitoring register using > hardcoded addresses in platform code! > > This series also fixes a minor regression introduced by adding the > "renesas,apmu" enable-method on Lager, where secondary CPU cores are no > longer available when hardware debug mode is enabled. > > This has been boot-tested on r8a7791/koelsch (both debug mode and normal > mode), on r8a7790/lager, r8a7792/blanche, and r8a7793/gose (normal mode > only), and on r8a7794/alt (normal mode UP only). Its core parts have > been in renesas-drivers since renesas-drivers-2016-09-06-v4.8-rc5. > > Changes compared to v1: > - Add Tested-by, > - New patch "ARM: shmobile: rcar-gen2: Remove unused > rcar_gen2_read_mode_pins()". > > This series is against renesas-devel-20161202-v4.9-rc7, with my > "rcar-rst" branch merged in, which resulted in a merge conflict. > The latter dependency is present in clk-next, and expected to land > upstream in v4.10-rc1. > > For your convenience (and for conflict resolution), this series is also > available in the topic/rcar-secondary-booting-in-debug-mode-v2 branch of > my renesas-drivers git repository at > git://git.kernel.org/pub/scm/linux/kernel/git/geert/renesas-drivers.git > > Thanks for applying! Thanks, I have tentatively queued this up for v4.11. I have pulled in the rcar-rst dependency with the expectation ttha it will disappear when I rebase on v4.10-rc1 once it has been released.
