From 94a8cfceaa7ee7e7187c5de074eb5138a6b77dcf Mon Sep 17 00:00:00 2001 From: Peter Griffin Date: Tue, 9 Jun 2015 15:33:00 +0200 Subject: [PATCH] ARM: STi: Add code to release secondary cores from holding pen. Most upstream devs boot STi platform via JTAG which abuses the boot process by setting the PC of secondary cores directly. As a consquence, booting STi platforms via u-boot results in only the primary core being brought up as the code to manage the holding pen is not upstream. This patch adds the necessary code to bring the secondary cores out of the holding pen. It uses the cpu-release-addr DT property to get the address of the holding pen from the bootloader. With this patch booting upstream kernels via u-boot works correctly: [ 0.045456] CPU: Testing write buffer coherency: ok [ 0.045597] CPU0: thread -1, cpu 0, socket 0, mpidr 80000000 [ 0.045734] Setting up static identity map for 0x40209000 - 0x40209098 [ 0.065047] CPU1: thread -1, cpu 1, socket 0, mpidr 80000001 [ 0.065081] Brought up 2 CPUs [ 0.065089] SMP: Total of 2 processors activated (5983.43 BogoMIPS). [ 0.065092] CPU: All CPU(s) started in SVC mode. Signed-off-by: Peter Griffin Acked-by: Maxime Coquelin Signed-off-by: Maxime Coquelin --- arch/arm/mach-sti/headsmp.S | 1 + arch/arm/mach-sti/platsmp.c | 55 +++++++++++++++++++++++++++++++++++-- arch/arm/mach-sti/smp.h | 2 ++ 3 files changed, 55 insertions(+), 3 deletions(-) diff --git a/arch/arm/mach-sti/headsmp.S b/arch/arm/mach-sti/headsmp.S index 4c09bae86edf..e0ad451700d5 100644 --- a/arch/arm/mach-sti/headsmp.S +++ b/arch/arm/mach-sti/headsmp.S @@ -37,6 +37,7 @@ pen: ldr r7, [r6] * should now contain the SVC stack for this core */ b secondary_startup +ENDPROC(sti_secondary_startup) 1: .long . .long pen_release diff --git a/arch/arm/mach-sti/platsmp.c b/arch/arm/mach-sti/platsmp.c index d4b624f8dfcb..86bb48d81ec1 100644 --- a/arch/arm/mach-sti/platsmp.c +++ b/arch/arm/mach-sti/platsmp.c @@ -20,6 +20,7 @@ #include #include #include +#include #include #include @@ -99,14 +100,62 @@ static int sti_boot_secondary(unsigned int cpu, struct task_struct *idle) static void __init sti_smp_prepare_cpus(unsigned int max_cpus) { - void __iomem *scu_base = NULL; - struct device_node *np = of_find_compatible_node( - NULL, NULL, "arm,cortex-a9-scu"); + struct device_node *np; + void __iomem *scu_base; + u32 __iomem *cpu_strt_ptr; + u32 release_phys; + int cpu; + unsigned long entry_pa = virt_to_phys(sti_secondary_startup); + + np = of_find_compatible_node(NULL, NULL, "arm,cortex-a9-scu"); + if (np) { scu_base = of_iomap(np, 0); scu_enable(scu_base); of_node_put(np); } + + if (max_cpus <= 1) + return; + + for_each_possible_cpu(cpu) { + + np = of_get_cpu_node(cpu, NULL); + + if (!np) + continue; + + if (of_property_read_u32(np, "cpu-release-addr", + &release_phys)) { + pr_err("CPU %d: missing or invalid cpu-release-addr " + "property\n", cpu); + continue; + } + + /* + * holding pen is usually configured in SBC DMEM but can also be + * in RAM. + */ + + if (!memblock_is_memory(release_phys)) + cpu_strt_ptr = + ioremap(release_phys, sizeof(release_phys)); + else + cpu_strt_ptr = + (u32 __iomem *)phys_to_virt(release_phys); + + __raw_writel(entry_pa, cpu_strt_ptr); + + /* + * wmb so that data is actually written + * before cache flush is done + */ + smp_wmb(); + sync_cache_w(cpu_strt_ptr); + + if (!memblock_is_memory(release_phys)) + iounmap(cpu_strt_ptr); + } } struct smp_operations __initdata sti_smp_ops = { diff --git a/arch/arm/mach-sti/smp.h b/arch/arm/mach-sti/smp.h index 1871b72b1a7e..ae22707d301f 100644 --- a/arch/arm/mach-sti/smp.h +++ b/arch/arm/mach-sti/smp.h @@ -14,4 +14,6 @@ extern struct smp_operations sti_smp_ops; +void sti_secondary_startup(void); + #endif -- 2.34.1