Hi Simon, Magnus, On Mon, Aug 22, 2016 at 4:44 PM, Geert Uytterhoeven <geert+renesas@xxxxxxxxx> wrote: > This patch series is an attempt to allow 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 cores first resume from power-shutoff. 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. > > 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. > > This series has been boot-tested on r8a7791/koelsch (both debug mode and > normal mode), on r8a7790/lager and r8a7793/gose (normal mode only), and > on r8a7794/alt (normal mode UP only). Any comments? Any objection to applying this series? I've been running my Koelsch with MD21=1 since I posted this series, and it has been included in renesas-drivers since the beginning of September. My main motivation to push this is that it removes two more users of rcar_gen2_read_mode_pins(). After this, the only remaining user is the clock driver, invoked from rcar_gen2_timer_init(). Thanks! Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds