stm32mp1: psci: add synchronization with ROM code
Use SGI0 interruption and TAMP_BACKUP_MAGIC_NUMBER
to synchronize the core1 boot sequence requested by
core0 in psci_cpu_on():
- a initial interruption is needed in ROM code after
RCC_MP_GRSTCSETR_MPUP1RST (psci_cpu_off)
- the ROM code set to 0 the 2 registers
+ TAMP_BACKUP_BRANCH_ADDRESS
+ TAMP_BACKUP_MAGIC_NUMBER
when magic is not egual to
BOOT_API_A7_CORE0_MAGIC_NUMBER
This patch solve issue for cpu1 restart in kernel.
echo 0 > /sys/devices/system/cpu/cpu1/online
echo 1 > /sys/devices/system/cpu/cpu1/online
Signed-off-by: Patrick Delaunay <patrick.delaunay@st.com>
diff --git a/arch/arm/mach-stm32mp/psci.c b/arch/arm/mach-stm32mp/psci.c
index c2dff38..139bb09 100644
--- a/arch/arm/mach-stm32mp/psci.c
+++ b/arch/arm/mach-stm32mp/psci.c
@@ -47,14 +47,14 @@
return (periphbase & CBAR_MASK) + GIC_DIST_OFFSET;
}
-static void __secure stm32mp_smp_kick_all_cpus(void)
+static void __secure stm32mp_raise_sgi0(int cpu)
{
u32 gic_dist_addr;
gic_dist_addr = stm32mp_get_gicd_base_address();
- /* kick all CPUs (except this one) by writing to GICD_SGIR */
- writel(1U << 24, gic_dist_addr + GICD_SGIR);
+ /* ask cpu with SGI0 */
+ writel((BIT(cpu) << 16), gic_dist_addr + GICD_SGIR);
}
void __secure psci_arch_cpu_entry(void)
@@ -62,6 +62,9 @@
u32 cpu = psci_get_cpu_id();
psci_set_state(cpu, PSCI_AFFINITY_LEVEL_ON);
+
+ /* reset magic in TAMP register */
+ writel(0xFFFFFFFF, TAMP_BACKUP_MAGIC_NUMBER);
}
int __secure psci_features(u32 function_id, u32 psci_fid)
@@ -127,6 +130,16 @@
if (psci_state[cpu] == PSCI_AFFINITY_LEVEL_ON)
return ARM_PSCI_RET_ALREADY_ON;
+ /* reset magic in TAMP register */
+ if (readl(TAMP_BACKUP_MAGIC_NUMBER))
+ writel(0xFFFFFFFF, TAMP_BACKUP_MAGIC_NUMBER);
+ /*
+ * ROM code need a first SGI0 after core reset
+ * core is ready when magic is set to 0 in ROM code
+ */
+ while (readl(TAMP_BACKUP_MAGIC_NUMBER))
+ stm32mp_raise_sgi0(cpu);
+
/* store target PC and context id*/
psci_save(cpu, pc, context_id);
@@ -142,7 +155,8 @@
writel(BOOT_API_A7_CORE0_MAGIC_NUMBER,
TAMP_BACKUP_MAGIC_NUMBER);
- stm32mp_smp_kick_all_cpus();
+ /* Generate an IT to start the core */
+ stm32mp_raise_sgi0(cpu);
return ARM_PSCI_RET_SUCCESS;
}