Introduce SCP power management abstraction

This patch introduces an additional layer of abstraction between
CSS power management hooks and the SCPI driver. A new set of APIs
are introduced in order to abstract out power management operations
from underlying communication mechanism with the SCP.

The SCPI and the associated MHU drivers are moved into a `drivers`
folder in CSS. The new SCP communication abstraction layer is added
in the `drivers/scp` folder. The existing CSS power management
uses the new APIs to reflect this abstraction.

Change-Id: I7d775129fc0558e9703c2724523fb8f0a916838c
Signed-off-by: Soby Mathew <soby.mathew@arm.com>

10 files changed, 250 insertions, 108 deletions

diff --git a/include/plat/arm/css/common/css_pm.h b/include/plat/arm/css/common/css_pm.h
index 4a6ca816..489275e9 100644
--- a/include/plat/arm/css/common/css_pm.h
+++ b/include/plat/arm/css/common/css_pm.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2015, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2015-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
@@ -35,6 +35,12 @@
 #include <psci.h>
 #include <types.h>
 
+/* Macros to read the CSS power domain state */
+#define CSS_CORE_PWR_STATE(state)	(state)->pwr_domain_state[ARM_PWR_LVL0]
+#define CSS_CLUSTER_PWR_STATE(state)	(state)->pwr_domain_state[ARM_PWR_LVL1]
+#define CSS_SYSTEM_PWR_STATE(state)	((PLAT_MAX_PWR_LVL > ARM_PWR_LVL1) ?\
+				(state)->pwr_domain_state[ARM_PWR_LVL2] : 0)
+
 int css_pwr_domain_on(u_register_t mpidr);
 void css_pwr_domain_on_finish(const psci_power_state_t *target_state);
 void css_pwr_domain_off(const psci_power_state_t *target_state);
diff --git a/plat/arm/css/common/css_common.mk b/plat/arm/css/common/css_common.mk
index 65e125ea..86ba6df5 100644
--- a/plat/arm/css/common/css_common.mk
+++ b/plat/arm/css/common/css_common.mk
@@ -41,18 +41,18 @@ PLAT_BL_COMMON_SOURCES	+=	plat/arm/css/common/aarch64/css_helpers.S
 BL1_SOURCES		+=	plat/arm/css/common/css_bl1_setup.c
 
 BL2_SOURCES		+=	plat/arm/css/common/css_bl2_setup.c		\
-				plat/arm/css/common/css_mhu.c			\
-				plat/arm/css/common/css_scpi.c
+				plat/arm/css/drivers/scpi/css_mhu.c		\
+				plat/arm/css/drivers/scpi/css_scpi.c
 
 BL2U_SOURCES		+=	plat/arm/css/common/css_bl2u_setup.c		\
-				plat/arm/css/common/css_mhu.c			\
-				plat/arm/css/common/css_scpi.c
-
-BL31_SOURCES		+=	plat/arm/css/common/css_mhu.c			\
-				plat/arm/css/common/css_pm.c			\
-				plat/arm/css/common/css_scpi.c			\
-				plat/arm/css/common/css_topology.c
-
+				plat/arm/css/drivers/scpi/css_mhu.c		\
+				plat/arm/css/drivers/scpi/css_scpi.c
+
+BL31_SOURCES		+=	plat/arm/css/common/css_pm.c			\
+				plat/arm/css/common/css_topology.c		\
+				plat/arm/css/drivers/scp/css_pm_scpi.c		\
+				plat/arm/css/drivers/scpi/css_mhu.c		\
+				plat/arm/css/drivers/scpi/css_scpi.c
 
 ifneq (${RESET_TO_BL31},0)
   $(error "Using BL31 as the reset vector is not supported on CSS platforms. \
diff --git a/plat/arm/css/common/css_pm.c b/plat/arm/css/common/css_pm.c
index 7607f617..65d27336 100644
--- a/plat/arm/css/common/css_pm.c
+++ b/plat/arm/css/common/css_pm.c
@@ -37,13 +37,7 @@
 #include <plat_arm.h>
 #include <platform.h>
 #include <platform_def.h>
-#include "css_scpi.h"
-
-/* Macros to read the CSS power domain state */
-#define CSS_CORE_PWR_STATE(state)	(state)->pwr_domain_state[ARM_PWR_LVL0]
-#define CSS_CLUSTER_PWR_STATE(state)	(state)->pwr_domain_state[ARM_PWR_LVL1]
-#define CSS_SYSTEM_PWR_STATE(state)	((PLAT_MAX_PWR_LVL > ARM_PWR_LVL1) ?\
-				(state)->pwr_domain_state[ARM_PWR_LVL2] : 0)
+#include "../drivers/scp/css_scp.h"
 
 /* Allow CSS platforms to override `plat_arm_psci_pm_ops` */
 #pragma weak plat_arm_psci_pm_ops
@@ -87,12 +81,7 @@ CASSERT(PLAT_MAX_PWR_LVL >= ARM_PWR_LVL1,
  ******************************************************************************/
 int css_pwr_domain_on(u_register_t mpidr)
 {
-	/*
-	 * SCP takes care of powering up parent power domains so we
-	 * only need to care about level 0
-	 */
-	scpi_set_css_power_state(mpidr, scpi_power_on, scpi_power_on,
-				 scpi_power_on);
+	css_scp_on(mpidr);
 
 	return PSCI_E_SUCCESS;
 }
@@ -140,30 +129,12 @@ void css_pwr_domain_on_finish(const psci_power_state_t *target_state)
  ******************************************************************************/
 static void css_power_down_common(const psci_power_state_t *target_state)
 {
-	uint32_t cluster_state = scpi_power_on;
-	uint32_t system_state = scpi_power_on;
-
 	/* Prevent interrupts from spuriously waking up this cpu */
 	plat_arm_gic_cpuif_disable();
 
-	/* Check if power down at system power domain level is requested */
-	if (CSS_SYSTEM_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF)
-			system_state = scpi_power_retention;
-
 	/* Cluster is to be turned off, so disable coherency */
-	if (CSS_CLUSTER_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF) {
+	if (CSS_CLUSTER_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF)
 		plat_arm_interconnect_exit_coherency();
-		cluster_state = scpi_power_off;
-	}
-
-	/*
-	 * Ask the SCP to power down the appropriate components depending upon
-	 * their state.
-	 */
-	scpi_set_css_power_state(read_mpidr_el1(),
-				 scpi_power_off,
-				 cluster_state,
-				 system_state);
 }
 
 /*******************************************************************************
@@ -174,6 +145,7 @@ void css_pwr_domain_off(const psci_power_state_t *target_state)
 {
 	assert(CSS_CORE_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF);
 	css_power_down_common(target_state);
+	css_scp_off(target_state);
 }
 
 /*******************************************************************************
@@ -191,6 +163,7 @@ void css_pwr_domain_suspend(const psci_power_state_t *target_state)
 
 	assert(CSS_CORE_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF);
 	css_power_down_common(target_state);
+	css_scp_suspend(target_state);
 }
 
 /*******************************************************************************
@@ -222,34 +195,12 @@ void css_pwr_domain_suspend_finish(
  ******************************************************************************/
 void __dead2 css_system_off(void)
 {
-	uint32_t response;
-
-	/* Send the power down request to the SCP */
-	response = scpi_sys_power_state(scpi_system_shutdown);
-
-	if (response != SCP_OK) {
-		ERROR("CSS System Off: SCP error %u.\n", response);
-		panic();
-	}
-	wfi();
-	ERROR("CSS System Off: operation not handled.\n");
-	panic();
+	css_scp_sys_shutdown();
 }
 
 void __dead2 css_system_reset(void)
 {
-	uint32_t response;
-
-	/* Send the system reset request to the SCP */
-	response = scpi_sys_power_state(scpi_system_reboot);
-
-	if (response != SCP_OK) {
-		ERROR("CSS System Reset: SCP error %u.\n", response);
-		panic();
-	}
-	wfi();
-	ERROR("CSS System Reset: operation not handled.\n");
-	panic();
+	css_scp_sys_reboot();
 }
 
 /*******************************************************************************
@@ -303,36 +254,7 @@ void css_get_sys_suspend_power_state(psci_power_state_t *req_state)
  ******************************************************************************/
 int css_node_hw_state(u_register_t mpidr, unsigned int power_level)
 {
-	int rc, element;
-	unsigned int cpu_state, cluster_state;
-
-	/*
-	 * The format of 'power_level' is implementation-defined, but 0 must
-	 * mean a CPU. We also allow 1 to denote the cluster
-	 */
-	if (power_level != ARM_PWR_LVL0 && power_level != ARM_PWR_LVL1)
-		return PSCI_E_INVALID_PARAMS;
-
-	/* Query SCP */
-	rc = scpi_get_css_power_state(mpidr, &cpu_state, &cluster_state);
-	if (rc != 0)
-		return PSCI_E_INVALID_PARAMS;
-
-	/* Map power states of CPU and cluster to expected PSCI return codes */
-	if (power_level == ARM_PWR_LVL0) {
-		/*
-		 * The CPU state returned by SCP is an 8-bit bit mask
-		 * corresponding to each CPU in the cluster
-		 */
-		element = mpidr & MPIDR_AFFLVL_MASK;
-		return CSS_CPU_PWR_STATE(cpu_state, element) ==
-			CSS_CPU_PWR_STATE_ON ? HW_ON : HW_OFF;
-	} else {
-		assert(cluster_state == CSS_CLUSTER_PWR_STATE_ON ||
-				cluster_state == CSS_CLUSTER_PWR_STATE_OFF);
-		return cluster_state == CSS_CLUSTER_PWR_STATE_ON ? HW_ON :
-			HW_OFF;
-	}
+	return css_scp_get_power_state(mpidr, power_level);
 }
 
 /*******************************************************************************
diff --git a/plat/arm/css/common/css_scp_bootloader.c b/plat/arm/css/common/css_scp_bootloader.c
index d3f671e2..049afe4e 100644
--- a/plat/arm/css/common/css_scp_bootloader.c
+++ b/plat/arm/css/common/css_scp_bootloader.c
@@ -34,9 +34,9 @@
 #include <debug.h>
 #include <platform.h>
 #include <stdint.h>
-#include "css_mhu.h"
+#include "../drivers/scpi/css_mhu.h"
+#include "../drivers/scpi/css_scpi.h"
 #include "css_scp_bootloader.h"
-#include "css_scpi.h"
 
 /* ID of the MHU slot used for the BOM protocol */
 #define BOM_MHU_SLOT_ID		0
diff --git a/plat/arm/css/drivers/scp/css_pm_scpi.c b/plat/arm/css/drivers/scp/css_pm_scpi.c
new file mode 100644
index 00000000..e22504d1
--- /dev/null
+++ b/plat/arm/css/drivers/scp/css_pm_scpi.c
@@ -0,0 +1,166 @@
+/*
+ * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <arch_helpers.h>
+#include <assert.h>
+#include <css_pm.h>
+#include <debug.h>
+#include "../scpi/css_scpi.h"
+#include "css_scp.h"
+
+/*
+ * This file implements the SCP power management functions using SCPI protocol.
+ */
+
+/*
+ * Helper function to inform power down state to SCP.
+ */
+void css_scp_suspend(const psci_power_state_t *target_state)
+{
+	uint32_t cluster_state = scpi_power_on;
+	uint32_t system_state = scpi_power_on;
+
+	/* Check if power down at system power domain level is requested */
+	if (CSS_SYSTEM_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF)
+		system_state = scpi_power_retention;
+
+	/* Cluster is to be turned off, so disable coherency */
+	if (CSS_CLUSTER_PWR_STATE(target_state) == ARM_LOCAL_STATE_OFF)
+		cluster_state = scpi_power_off;
+
+	/*
+	 * Ask the SCP to power down the appropriate components depending upon
+	 * their state.
+	 */
+	scpi_set_css_power_state(read_mpidr_el1(),
+				 scpi_power_off,
+				 cluster_state,
+				 system_state);
+}
+
+/*
+ * Helper function to turn off a CPU power domain and its parent power domains
+ * if applicable. Since SCPI doesn't differentiate between OFF and suspend, we
+ * call the suspend helper here.
+ */
+void css_scp_off(const psci_power_state_t *target_state)
+{
+	css_scp_suspend(target_state);
+}
+
+/*
+ * Helper function to turn ON a CPU power domain and its parent power domains
+ * if applicable.
+ */
+void css_scp_on(u_register_t mpidr)
+{
+	/*
+	 * SCP takes care of powering up parent power domains so we
+	 * only need to care about level 0
+	 */
+	scpi_set_css_power_state(mpidr, scpi_power_on, scpi_power_on,
+				 scpi_power_on);
+}
+
+/*
+ * Helper function to get the power state of a power domain node as reported
+ * by the SCP.
+ */
+int css_scp_get_power_state(u_register_t mpidr, unsigned int power_level)
+{
+	int rc, element;
+	unsigned int cpu_state, cluster_state;
+
+	/*
+	 * The format of 'power_level' is implementation-defined, but 0 must
+	 * mean a CPU. We also allow 1 to denote the cluster
+	 */
+	if (power_level != ARM_PWR_LVL0 && power_level != ARM_PWR_LVL1)
+		return PSCI_E_INVALID_PARAMS;
+
+	/* Query SCP */
+	rc = scpi_get_css_power_state(mpidr, &cpu_state, &cluster_state);
+	if (rc != 0)
+		return PSCI_E_INVALID_PARAMS;
+
+	/* Map power states of CPU and cluster to expected PSCI return codes */
+	if (power_level == ARM_PWR_LVL0) {
+		/*
+		 * The CPU state returned by SCP is an 8-bit bit mask
+		 * corresponding to each CPU in the cluster
+		 */
+		element = mpidr & MPIDR_AFFLVL_MASK;
+		return CSS_CPU_PWR_STATE(cpu_state, element) ==
+			CSS_CPU_PWR_STATE_ON ? HW_ON : HW_OFF;
+	} else {
+		assert(cluster_state == CSS_CLUSTER_PWR_STATE_ON ||
+				cluster_state == CSS_CLUSTER_PWR_STATE_OFF);
+		return cluster_state == CSS_CLUSTER_PWR_STATE_ON ? HW_ON :
+			HW_OFF;
+	}
+}
+
+/*
+ * Helper function to shutdown the system via SCPI.
+ */
+void __dead2 css_scp_sys_shutdown(void)
+{
+	uint32_t response;
+
+	/* Send the power down request to the SCP */
+	response = scpi_sys_power_state(scpi_system_shutdown);
+
+	if (response != SCP_OK) {
+		ERROR("CSS System Off: SCP error %u.\n", response);
+		panic();
+	}
+	wfi();
+	ERROR("CSS System Off: operation not handled.\n");
+	panic();
+}
+
+/*
+ * Helper function to reset the system via SCPI.
+ */
+void __dead2 css_scp_sys_reboot(void)
+{
+	uint32_t response;
+
+	/* Send the system reset request to the SCP */
+	response = scpi_sys_power_state(scpi_system_reboot);
+
+	if (response != SCP_OK) {
+		ERROR("CSS System Reset: SCP error %u.\n", response);
+		panic();
+	}
+	wfi();
+	ERROR("CSS System Reset: operation not handled.\n");
+	panic();
+}
diff --git a/plat/arm/css/drivers/scp/css_scp.h b/plat/arm/css/drivers/scp/css_scp.h
new file mode 100644
index 00000000..a12798b6
--- /dev/null
+++ b/plat/arm/css/drivers/scp/css_scp.h
@@ -0,0 +1,43 @@
+/*
+ * Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * Redistributions of source code must retain the above copyright notice, this
+ * list of conditions and the following disclaimer.
+ *
+ * Redistributions in binary form must reproduce the above copyright notice,
+ * this list of conditions and the following disclaimer in the documentation
+ * and/or other materials provided with the distribution.
+ *
+ * Neither the name of ARM nor the names of its contributors may be used
+ * to endorse or promote products derived from this software without specific
+ * prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#ifndef __CSS_SCP_H__
+#define __CSS_SCP_H__
+
+#include <psci.h>
+
+void css_scp_suspend(const psci_power_state_t *target_state);
+void css_scp_off(const psci_power_state_t *target_state);
+void css_scp_on(u_register_t mpidr);
+int css_scp_get_power_state(u_register_t mpidr, unsigned int power_level);
+void __dead2 css_scp_sys_shutdown(void);
+void __dead2 css_scp_sys_reboot(void);
+
+#endif	/* __CSS_SCP_H__ */
diff --git a/plat/arm/css/common/css_mhu.c b/plat/arm/css/drivers/scpi/css_mhu.c
index 265d6c25..302286fc 100644
--- a/plat/arm/css/common/css_mhu.c
+++ b/plat/arm/css/drivers/scpi/css_mhu.c
@@ -33,8 +33,8 @@
 #include <bakery_lock.h>
 #include <css_def.h>
 #include <mmio.h>
-#include <platform_def.h>
 #include <plat_arm.h>
+#include <platform_def.h>
 #include "css_mhu.h"
 
 /* SCP MHU secure channel registers */
diff --git a/plat/arm/css/common/css_mhu.h b/plat/arm/css/drivers/scpi/css_mhu.h
index 2175cdf9..6973a140 100644
--- a/plat/arm/css/common/css_mhu.h
+++ b/plat/arm/css/drivers/scpi/css_mhu.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2014-2015, ARM Limited and Contributors. All rights reserved.
+ * Copyright (c) 2014-2016, ARM Limited and Contributors. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
diff --git a/plat/arm/css/common/css_scpi.c b/plat/arm/css/drivers/scpi/css_scpi.c
index 90a8939d..f419abd0 100644
--- a/plat/arm/css/common/css_scpi.c
+++ b/plat/arm/css/drivers/scpi/css_scpi.c
@@ -63,9 +63,11 @@ static void scpi_secure_message_start(void)
 
 static void scpi_secure_message_send(size_t payload_size)
 {
-	/* Ensure that any write to the SCPI payload area is seen by SCP before
+	/*
+	 * Ensure that any write to the SCPI payload area is seen by SCP before
 	 * we write to the MHU register. If these 2 writes were reordered by
-	 * the CPU then SCP would read stale payload data */
+	 * the CPU then SCP would read stale payload data
+	 */
 	dmbst();
 
 	mhu_secure_message_send(SCPI_MHU_SLOT_ID);
@@ -86,9 +88,11 @@ static void scpi_secure_message_receive(scpi_cmd_t *cmd)
 		panic();
 	}
 
-	/* Ensure that any read to the SCPI payload area is done after reading
+	/*
+	 * Ensure that any read to the SCPI payload area is done after reading
 	 * the MHU register. If these 2 reads were reordered then the CPU would
-	 * read invalid payload data */
+	 * read invalid payload data
+	 */
 	dmbld();
 
 	memcpy(cmd, (void *) SCPI_SHARED_MEM_SCP_TO_AP, sizeof(*cmd));
@@ -137,8 +141,9 @@ int scpi_wait_ready(void)
 	return status == SCP_OK ? 0 : -1;
 }
 
-void scpi_set_css_power_state(unsigned mpidr, scpi_power_state_t cpu_state,
-		scpi_power_state_t cluster_state, scpi_power_state_t css_state)
+void scpi_set_css_power_state(unsigned int mpidr,
+		scpi_power_state_t cpu_state, scpi_power_state_t cluster_state,
+		scpi_power_state_t css_state)
 {
 	scpi_cmd_t *cmd;
 	uint32_t state = 0;
diff --git a/plat/arm/css/common/css_scpi.h b/plat/arm/css/drivers/scpi/css_scpi.h
index 1fb55e4d..d1e7cba4 100644
--- a/plat/arm/css/common/css_scpi.h
+++ b/plat/arm/css/drivers/scpi/css_scpi.h
@@ -122,7 +122,7 @@ typedef enum {
 } scpi_system_state_t;
 
 extern int scpi_wait_ready(void);
-extern void scpi_set_css_power_state(unsigned mpidr,
+extern void scpi_set_css_power_state(unsigned int mpidr,
 					scpi_power_state_t cpu_state,
 					scpi_power_state_t cluster_state,
 					scpi_power_state_t css_state);