From mboxrd@z Thu Jan 1 00:00:00 1970 From: Geert Uytterhoeven Date: Tue, 13 Jan 2015 09:41:27 +0000 Subject: Re: ARM: shmobile: sh73a0: CPU1 failed to come online (Re: [PATCH 0/4] ARM: shmobile: r8a7740/armadi Message-Id: List-Id: References: <20141117151241.GR4042@n2100.arm.linux.org.uk> In-Reply-To: <20141117151241.GR4042@n2100.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-arm-kernel@lists.infradead.org On Mon, Nov 17, 2014 at 4:12 PM, Russell King - ARM Linux wrote: > On Mon, Nov 17, 2014 at 02:57:46PM +0100, Geert Uytterhoeven wrote: >> I tried to convert sh73a0, but it doesn't work, due to problems >> bringing up the second >> CPU core. >> >> Details: >> - l2x0_of_init() is called much earlier than l2x0_init(). >> When the L2 cache is enabled, initialization of the second CPU core of >> sh73a0 (Dual-core Cortex-A9) fails. > > Missing L2 cache flushes for (any) the secondary core data/trampoline? Thanks, I added a few cache flushes, so far it didn't help... >> - As jiffies are not yet incrementing at that point (they are on r8a7791?), >> timeouts don't work, and the kernel hangs at the >> wait_for_completion_timeout() call in arch/arm/kernel/smp.c:__cpu_up(). > > That sounds bad: > > start_kernel() -> rest_init() -> kernel_thread(kernel_init) > > kernel_init() -> kernel_init_freeable() -> smp_init() -> (for each CPU) cpu_up() > > By the time we get to rest_init(), init_IRQ(), time_init(), > local_irq_enable(), late_time_init(), calibrate_delay(), etc have all > been called, so if jiffies is not incrementing in __cpu_up(), that's > a big problem. That was due to the missing arm,cortex-a9-twd-timer timer, which also broke CONFIG_CPU_IDLE=y. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org 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