This patch adds cpu hotplug support, previous imx_cpu_off implementation is NOT safe, a CPU can NOT power down itself in runtime, it will cause system bus hang due to pending transaction. So need to use other online CPU to kill it when it is ready for killed.
Here use SRC parameter register and a magic number of ~0 as handshake for killing a offline CPU, when the online CPU checks the psci_affinity_info, it will help kill the offline CPU according to the magic number stored in SRC parameter register.
Signed-off-by: Anson Huang Anson.Huang@nxp.com --- arch/arm/mach-imx/mx7/psci-mx7.c | 31 ++++++++++++++++++++++++++++--- arch/arm/mach-imx/mx7/psci.S | 14 ++++++++++++++ 2 files changed, 42 insertions(+), 3 deletions(-)
diff --git a/arch/arm/mach-imx/mx7/psci-mx7.c b/arch/arm/mach-imx/mx7/psci-mx7.c index 7dc49bd..6f69fd3 100644 --- a/arch/arm/mach-imx/mx7/psci-mx7.c +++ b/arch/arm/mach-imx/mx7/psci-mx7.c @@ -77,12 +77,37 @@ __secure int imx_cpu_on(int fn, int cpu, int pc)
__secure int imx_cpu_off(int cpu) { - imx_enable_cpu_ca7(cpu, false); - imx_gpcv2_set_core1_power(false); - writel(0, SRC_BASE_ADDR + cpu * 8 + SRC_GPR1_MX7D + 4); + /* + * We use the cpu jumping argument register to sync with + * imx_cpu_affinity() which is running on cpu0 to kill the cpu. + */ + writel(~0, SRC_BASE_ADDR + cpu * 8 + SRC_GPR1_MX7D + 4); + return 0; }
+__secure int imx_cpu_affinity(int cpu) +{ + u32 val; + + /* always ON for CPU0 */ + if (cpu == 0) + return PSCI_AFFINITY_LEVEL_ON; + + /* CPU1 is waiting for killed */ + if (readl(SRC_BASE_ADDR + cpu * 8 + SRC_GPR1_MX7D + 4) == ~0) { + imx_enable_cpu_ca7(cpu, false); + imx_gpcv2_set_core1_power(false); + writel(0, SRC_BASE_ADDR + cpu * 8 + SRC_GPR1_MX7D + 4); + return PSCI_AFFINITY_LEVEL_OFF; + } + + val = readl(SRC_BASE_ADDR + SRC_A7RCR1) & + (1 << BP_SRC_A7RCR1_A7_CORE1_ENABLE); + + return val ? PSCI_AFFINITY_LEVEL_ON : PSCI_AFFINITY_LEVEL_OFF; +} + __secure void imx_system_reset(void) { struct wdog_regs *wdog = (struct wdog_regs *)WDOG1_BASE_ADDR; diff --git a/arch/arm/mach-imx/mx7/psci.S b/arch/arm/mach-imx/mx7/psci.S index 89dcf88..d6d19d5 100644 --- a/arch/arm/mach-imx/mx7/psci.S +++ b/arch/arm/mach-imx/mx7/psci.S @@ -57,4 +57,18 @@ psci_system_off: 3: wfi b 3b
+.globl psci_affinity_info +psci_affinity_info: + push {lr} + + mov r0, #ARM_PSCI_RET_INVAL + cmp r2, #0 + bne out_affinity + + and r0, r1, #0xff + bl imx_cpu_affinity + +out_affinity: + pop {pc} + .popsection