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>
diff --git a/plat/arm/css/drivers/scpi/css_scpi.c b/plat/arm/css/drivers/scpi/css_scpi.c
new file mode 100644
index 0000000..f419abd
--- /dev/null
+++ b/plat/arm/css/drivers/scpi/css_scpi.c
@@ -0,0 +1,264 @@
+/*
+ * 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:
+ *
+ * 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_def.h>
+#include <debug.h>
+#include <platform.h>
+#include <string.h>
+#include "css_mhu.h"
+#include "css_scpi.h"
+
+#define SCPI_SHARED_MEM_SCP_TO_AP PLAT_CSS_SCP_COM_SHARED_MEM_BASE
+#define SCPI_SHARED_MEM_AP_TO_SCP (PLAT_CSS_SCP_COM_SHARED_MEM_BASE \
+ + 0x100)
+
+/* Header and payload addresses for commands from AP to SCP */
+#define SCPI_CMD_HEADER_AP_TO_SCP \
+ ((scpi_cmd_t *) SCPI_SHARED_MEM_AP_TO_SCP)
+#define SCPI_CMD_PAYLOAD_AP_TO_SCP \
+ ((void *) (SCPI_SHARED_MEM_AP_TO_SCP + sizeof(scpi_cmd_t)))
+
+/* Header and payload addresses for responses from SCP to AP */
+#define SCPI_RES_HEADER_SCP_TO_AP \
+ ((scpi_cmd_t *) SCPI_SHARED_MEM_SCP_TO_AP)
+#define SCPI_RES_PAYLOAD_SCP_TO_AP \
+ ((void *) (SCPI_SHARED_MEM_SCP_TO_AP + sizeof(scpi_cmd_t)))
+
+/* ID of the MHU slot used for the SCPI protocol */
+#define SCPI_MHU_SLOT_ID 0
+
+static void scpi_secure_message_start(void)
+{
+ mhu_secure_message_start(SCPI_MHU_SLOT_ID);
+}
+
+static void scpi_secure_message_send(size_t payload_size)
+{
+ /*
+ * 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
+ */
+ dmbst();
+
+ mhu_secure_message_send(SCPI_MHU_SLOT_ID);
+}
+
+static void scpi_secure_message_receive(scpi_cmd_t *cmd)
+{
+ uint32_t mhu_status;
+
+ assert(cmd != NULL);
+
+ mhu_status = mhu_secure_message_wait();
+
+ /* Expect an SCPI message, reject any other protocol */
+ if (mhu_status != (1 << SCPI_MHU_SLOT_ID)) {
+ ERROR("MHU: Unexpected protocol (MHU status: 0x%x)\n",
+ mhu_status);
+ panic();
+ }
+
+ /*
+ * 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
+ */
+ dmbld();
+
+ memcpy(cmd, (void *) SCPI_SHARED_MEM_SCP_TO_AP, sizeof(*cmd));
+}
+
+static void scpi_secure_message_end(void)
+{
+ mhu_secure_message_end(SCPI_MHU_SLOT_ID);
+}
+
+int scpi_wait_ready(void)
+{
+ scpi_cmd_t scpi_cmd;
+
+ VERBOSE("Waiting for SCP_READY command...\n");
+
+ /* Get a message from the SCP */
+ scpi_secure_message_start();
+ scpi_secure_message_receive(&scpi_cmd);
+ scpi_secure_message_end();
+
+ /* We are expecting 'SCP Ready', produce correct error if it's not */
+ scpi_status_t status = SCP_OK;
+ if (scpi_cmd.id != SCPI_CMD_SCP_READY) {
+ ERROR("Unexpected SCP command: expected command #%u, got command #%u\n",
+ SCPI_CMD_SCP_READY, scpi_cmd.id);
+ status = SCP_E_SUPPORT;
+ } else if (scpi_cmd.size != 0) {
+ ERROR("SCP_READY command has incorrect size: expected 0, got %u\n",
+ scpi_cmd.size);
+ status = SCP_E_SIZE;
+ }
+
+ VERBOSE("Sending response for SCP_READY command\n");
+
+ /*
+ * Send our response back to SCP.
+ * We are using the same SCPI header, just update the status field.
+ */
+ scpi_cmd.status = status;
+ scpi_secure_message_start();
+ memcpy((void *) SCPI_SHARED_MEM_AP_TO_SCP, &scpi_cmd, sizeof(scpi_cmd));
+ scpi_secure_message_send(0);
+ scpi_secure_message_end();
+
+ return status == SCP_OK ? 0 : -1;
+}
+
+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;
+ uint32_t *payload_addr;
+
+ state |= mpidr & 0x0f; /* CPU ID */
+ state |= (mpidr & 0xf00) >> 4; /* Cluster ID */
+ state |= cpu_state << 8;
+ state |= cluster_state << 12;
+ state |= css_state << 16;
+
+ scpi_secure_message_start();
+
+ /* Populate the command header */
+ cmd = SCPI_CMD_HEADER_AP_TO_SCP;
+ cmd->id = SCPI_CMD_SET_CSS_POWER_STATE;
+ cmd->set = SCPI_SET_NORMAL;
+ cmd->sender = 0;
+ cmd->size = sizeof(state);
+ /* Populate the command payload */
+ payload_addr = SCPI_CMD_PAYLOAD_AP_TO_SCP;
+ *payload_addr = state;
+ scpi_secure_message_send(sizeof(state));
+ /*
+ * SCP does not reply to this command in order to avoid MHU interrupts
+ * from the sender, which could interfere with its power state request.
+ */
+
+ scpi_secure_message_end();
+}
+
+/*
+ * Query and obtain CSS power state from SCP.
+ *
+ * In response to the query, SCP returns power states of all CPUs in all
+ * clusters of the system. The returned response is then filtered based on the
+ * supplied MPIDR. Power states of requested cluster and CPUs within are updated
+ * via. supplied non-NULL pointer arguments.
+ *
+ * Returns 0 on success, or -1 on errors.
+ */
+int scpi_get_css_power_state(unsigned int mpidr, unsigned int *cpu_state_p,
+ unsigned int *cluster_state_p)
+{
+ scpi_cmd_t *cmd;
+ scpi_cmd_t response;
+ int power_state, cpu, cluster, rc = -1;
+
+ /*
+ * Extract CPU and cluster membership of the given MPIDR. SCPI caters
+ * for only up to 0xf clusters, and 8 CPUs per cluster
+ */
+ cpu = mpidr & MPIDR_AFFLVL_MASK;
+ cluster = (mpidr >> MPIDR_AFF1_SHIFT) & MPIDR_AFFLVL_MASK;
+ if (cpu >= 8 || cluster >= 0xf)
+ return -1;
+
+ scpi_secure_message_start();
+
+ /* Populate request headers */
+ cmd = memset(SCPI_CMD_HEADER_AP_TO_SCP, 0, sizeof(*cmd));
+ cmd->id = SCPI_CMD_GET_CSS_POWER_STATE;
+
+ /*
+ * Send message and wait for SCP's response
+ */
+ scpi_secure_message_send(0);
+ scpi_secure_message_receive(&response);
+
+ if (response.status != SCP_OK)
+ goto exit;
+
+ /* Validate SCP response */
+ if (!CHECK_RESPONSE(response, cluster))
+ goto exit;
+
+ /* Extract power states for required cluster */
+ power_state = *(((uint16_t *) SCPI_RES_PAYLOAD_SCP_TO_AP) + cluster);
+ if (CLUSTER_ID(power_state) != cluster)
+ goto exit;
+
+ /* Update power state via. pointers */
+ if (cluster_state_p)
+ *cluster_state_p = CLUSTER_POWER_STATE(power_state);
+ if (cpu_state_p)
+ *cpu_state_p = CPU_POWER_STATE(power_state);
+ rc = 0;
+
+exit:
+ scpi_secure_message_end();
+ return rc;
+}
+
+uint32_t scpi_sys_power_state(scpi_system_state_t system_state)
+{
+ scpi_cmd_t *cmd;
+ uint8_t *payload_addr;
+ scpi_cmd_t response;
+
+ scpi_secure_message_start();
+
+ /* Populate the command header */
+ cmd = SCPI_CMD_HEADER_AP_TO_SCP;
+ cmd->id = SCPI_CMD_SYS_POWER_STATE;
+ cmd->set = 0;
+ cmd->sender = 0;
+ cmd->size = sizeof(*payload_addr);
+ /* Populate the command payload */
+ payload_addr = SCPI_CMD_PAYLOAD_AP_TO_SCP;
+ *payload_addr = system_state & 0xff;
+ scpi_secure_message_send(sizeof(*payload_addr));
+
+ scpi_secure_message_receive(&response);
+
+ scpi_secure_message_end();
+
+ return response.status;
+}