plat: imx8m: Fix the race condition during cpu hotplug

CPU hotplug & cpuidle have some race condition when doing CPU hotplug
stress test. different CPU cores have the chance to access the same
GPC register(A53_AD), so lock is necessary to do exlusive access.
Signed-off-by: Jacky Bai <ping.bai@nxp.com>
Change-Id: I1296592e05fa78429c3f0fac066951521db755e3

plat/imx/imx8m/gpc_common.c

@@ -18,6 +18,8 @@
 
 static uint32_t gpc_imr_offset[] = { IMR1_CORE0_A53, IMR1_CORE1_A53, IMR1_CORE2_A53, IMR1_CORE3_A53, };
 
+DEFINE_BAKERY_LOCK(gpc_lock);
+
 #pragma weak imx_set_cpu_pwr_off
 #pragma weak imx_set_cpu_pwr_on
 #pragma weak imx_set_cpu_lpm
@@ -38,16 +40,27 @@ void imx_set_cpu_secure_entry(unsigned int core_id, uintptr_t sec_entrypoint)
 
 void imx_set_cpu_pwr_off(unsigned int core_id)
 {
+
+	bakery_lock_get(&gpc_lock);
+
 	/* enable the wfi power down of the core */
 	mmio_setbits_32(IMX_GPC_BASE + LPCR_A53_AD, COREx_WFI_PDN(core_id));
+
+	bakery_lock_release(&gpc_lock);
+
 	/* assert the pcg pcr bit of the core */
 	mmio_setbits_32(IMX_GPC_BASE + COREx_PGC_PCR(core_id), 0x1);
 }
 
 void imx_set_cpu_pwr_on(unsigned int core_id)
 {
+	bakery_lock_get(&gpc_lock);
+
 	/* clear the wfi power down bit of the core */
 	mmio_clrbits_32(IMX_GPC_BASE + LPCR_A53_AD, COREx_WFI_PDN(core_id));
+
+	bakery_lock_release(&gpc_lock);
+
 	/* assert the ncpuporeset */
 	mmio_clrbits_32(IMX_SRC_BASE + SRC_A53RCR1, (1 << core_id));
 	/* assert the pcg pcr bit of the core */
@@ -67,6 +80,8 @@ void imx_set_cpu_pwr_on(unsigned int core_id)
 
 void imx_set_cpu_lpm(unsigned int core_id, bool pdn)
 {
+	bakery_lock_get(&gpc_lock);
+
 	if (pdn) {
 		/* enable the core WFI PDN & IRQ PUP */
 		mmio_setbits_32(IMX_GPC_BASE + LPCR_A53_AD, COREx_WFI_PDN(core_id) |
@@ -80,6 +95,8 @@ void imx_set_cpu_lpm(unsigned int core_id, bool pdn)
 		/* deassert the pcg pcr bit of the core */
 		mmio_clrbits_32(IMX_GPC_BASE + COREx_PGC_PCR(core_id), 0x1);
 	}
+
+	bakery_lock_release(&gpc_lock);
 }
 
 /*

plat/imx/imx8m/imx8mq/gpc.c

@@ -19,9 +19,14 @@
 /* use wfi power down the core */
 void imx_set_cpu_pwr_off(unsigned int core_id)
 {
+	bakery_lock_get(&gpc_lock);
+
 	/* enable the wfi power down of the core */
 	mmio_setbits_32(IMX_GPC_BASE + LPCR_A53_AD, COREx_WFI_PDN(core_id) |
 			(1 << (core_id + 20)));
+
+	bakery_lock_release(&gpc_lock);
+
 	/* assert the pcg pcr bit of the core */
 	mmio_setbits_32(IMX_GPC_BASE + COREx_PGC_PCR(core_id), 0x1);
 };
@@ -29,6 +34,8 @@ void imx_set_cpu_pwr_off(unsigned int core_id)
 /* if out of lpm, we need to do reverse steps */
 void imx_set_cpu_lpm(unsigned int core_id, bool pdn)
 {
+	bakery_lock_get(&gpc_lock);
+
 	if (pdn) {
 		/* enable the core WFI PDN & IRQ PUP */
 		mmio_setbits_32(IMX_GPC_BASE + LPCR_A53_AD, COREx_WFI_PDN(core_id) |
@@ -42,6 +49,8 @@ void imx_set_cpu_lpm(unsigned int core_id, bool pdn)
 		/* deassert the pcg pcr bit of the core */
 		mmio_setbits_32(IMX_GPC_BASE + COREx_PGC_PCR(core_id), 0x1);
 	}
+
+	bakery_lock_release(&gpc_lock);
 }
 
 void imx_pup_pdn_slot_config(int last_core, bool pdn)

plat/imx/imx8m/include/gpc.h

@@ -54,6 +54,8 @@ struct imx_pwr_domain {
 	bool always_on;
 };
 
+DECLARE_BAKERY_LOCK(gpc_lock);
+
 /* function declare */
 void imx_gpc_init(void);
 void imx_set_cpu_secure_entry(unsigned int core_index, uintptr_t sec_entrypoint);