CSS: Add SCMI driver for SCP
This patch adds the SCMI driver for communicating with SCP. The power
domain management and system power management protocol of the SCMI
specification[1] is implemented in the driver. The SCP power management
abstraction layer for SCMI for CSS power management is also added.
A new buid option `CSS_USE_SCMI_DRIVER` is introduced to select SCMI
driver over SCPI.
[1] ARM System Control and Management Interface v1.0 (SCMI)
Document number: ARM DEN 0056A
Change-Id: I67265615a17e679a2afe810b9b0043711ba09dbb
Signed-off-by: Soby Mathew <soby.mathew@arm.com>
diff --git a/plat/arm/css/drivers/scmi/scmi_common.c b/plat/arm/css/drivers/scmi/scmi_common.c
new file mode 100644
index 0000000..d0051c7
--- /dev/null
+++ b/plat/arm/css/drivers/scmi/scmi_common.c
@@ -0,0 +1,196 @@
+/*
+ * Copyright (c) 2017, ARM Limited and Contributors. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <arch_helpers.h>
+#include <assert.h>
+#include <debug.h>
+#include "scmi.h"
+#include "scmi_private.h"
+
+/*
+ * Private helper function to get exclusive access to SCMI channel.
+ */
+void scmi_get_channel(scmi_channel_t *ch)
+{
+ assert(ch->lock);
+ bakery_lock_get(ch->lock);
+
+ /* Make sure any previous command has finished */
+ assert(SCMI_IS_CHANNEL_FREE(
+ ((mailbox_mem_t *)(ch->info->scmi_mbx_mem))->status));
+}
+
+/*
+ * Private helper function to transfer ownership of channel from AP to SCP.
+ */
+void scmi_send_sync_command(scmi_channel_t *ch)
+{
+ mailbox_mem_t *mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
+
+ SCMI_MARK_CHANNEL_BUSY(mbx_mem->status);
+
+ /*
+ * Ensure that any write to the SCMI payload area is seen by SCP before
+ * we write to the doorbell register. If these 2 writes were reordered
+ * by the CPU then SCP would read stale payload data
+ */
+ dmbst();
+
+ SCMI_RING_DOORBELL(ch->info->db_reg_addr, ch->info->db_modify_mask,
+ ch->info->db_preserve_mask);
+
+ /*
+ * Ensure that the write to the doorbell register is ordered prior to
+ * checking whether the channel is free.
+ */
+ dmbsy();
+
+ /* Wait for channel to be free */
+ while (!SCMI_IS_CHANNEL_FREE(mbx_mem->status))
+ ;
+
+ /*
+ * Ensure that any read to the SCMI payload area is done after reading
+ * mailbox status. If these 2 reads were reordered then the CPU would
+ * read invalid payload data
+ */
+ dmbld();
+}
+
+/*
+ * Private helper function to release exclusive access to SCMI channel.
+ */
+void scmi_put_channel(scmi_channel_t *ch)
+{
+ /* Make sure any previous command has finished */
+ assert(SCMI_IS_CHANNEL_FREE(
+ ((mailbox_mem_t *)(ch->info->scmi_mbx_mem))->status));
+
+ assert(ch->lock);
+ bakery_lock_release(ch->lock);
+}
+
+/*
+ * API to query the SCMI protocol version.
+ */
+int scmi_proto_version(void *p, uint32_t proto_id, uint32_t *version)
+{
+ mailbox_mem_t *mbx_mem;
+ int token = 0, ret;
+ scmi_channel_t *ch = (scmi_channel_t *)p;
+
+ validate_scmi_channel(ch);
+
+ scmi_get_channel(ch);
+
+ mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
+ mbx_mem->msg_header = SCMI_MSG_CREATE(proto_id, SCMI_PROTO_VERSION_MSG,
+ token);
+ mbx_mem->len = SCMI_PROTO_VERSION_MSG_LEN;
+ mbx_mem->flags = SCMI_FLAG_RESP_POLL;
+
+ scmi_send_sync_command(ch);
+
+ /* Get the return values */
+ SCMI_PAYLOAD_RET_VAL2(mbx_mem->payload, ret, *version);
+ assert(mbx_mem->len == SCMI_PROTO_VERSION_RESP_LEN);
+ assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
+
+ scmi_put_channel(ch);
+
+ return ret;
+}
+
+/*
+ * API to query the protocol message attributes for a SCMI protocol.
+ */
+int scmi_proto_msg_attr(void *p, uint32_t proto_id,
+ uint32_t command_id, uint32_t *attr)
+{
+ mailbox_mem_t *mbx_mem;
+ int token = 0, ret;
+ scmi_channel_t *ch = (scmi_channel_t *)p;
+
+ validate_scmi_channel(ch);
+
+ scmi_get_channel(ch);
+
+ mbx_mem = (mailbox_mem_t *)(ch->info->scmi_mbx_mem);
+ mbx_mem->msg_header = SCMI_MSG_CREATE(proto_id,
+ SCMI_PROTO_MSG_ATTR_MSG, token);
+ mbx_mem->len = SCMI_PROTO_MSG_ATTR_MSG_LEN;
+ mbx_mem->flags = SCMI_FLAG_RESP_POLL;
+ SCMI_PAYLOAD_ARG1(mbx_mem->payload, command_id);
+
+ scmi_send_sync_command(ch);
+
+ /* Get the return values */
+ SCMI_PAYLOAD_RET_VAL2(mbx_mem->payload, ret, *attr);
+ assert(mbx_mem->len == SCMI_PROTO_MSG_ATTR_RESP_LEN);
+ assert(token == SCMI_MSG_GET_TOKEN(mbx_mem->msg_header));
+
+ scmi_put_channel(ch);
+
+ return ret;
+}
+
+/*
+ * SCMI Driver initialization API. Returns initialized channel on success
+ * or NULL on error. The return type is an opaque void pointer.
+ */
+void *scmi_init(scmi_channel_t *ch)
+{
+ uint32_t version;
+ int ret;
+
+ assert(ch && ch->info);
+ assert(ch->info->db_reg_addr);
+ assert(ch->info->db_modify_mask);
+ assert(ch->info->db_preserve_mask);
+
+ assert(ch->lock);
+
+ bakery_lock_init(ch->lock);
+
+ ch->is_initialized = 1;
+
+ ret = scmi_proto_version(ch, SCMI_PWR_DMN_PROTO_ID, &version);
+ if (ret != SCMI_E_SUCCESS) {
+ WARN("SCMI power domain protocol version message failed");
+ goto error;
+ }
+
+ if (!is_scmi_version_compatible(SCMI_PWR_DMN_PROTO_VER, version)) {
+ WARN("SCMI power domain protocol version 0x%x incompatible with driver version 0x%x",
+ version, SCMI_PWR_DMN_PROTO_VER);
+ goto error;
+ }
+
+ VERBOSE("SCMI power domain protocol version 0x%x detected\n", version);
+
+ ret = scmi_proto_version(ch, SCMI_SYS_PWR_PROTO_ID, &version);
+ if ((ret != SCMI_E_SUCCESS)) {
+ WARN("SCMI system power protocol version message failed");
+ goto error;
+ }
+
+ if (!is_scmi_version_compatible(SCMI_SYS_PWR_PROTO_VER, version)) {
+ WARN("SCMI system power management protocol version 0x%x incompatible with driver version 0x%x",
+ version, SCMI_SYS_PWR_PROTO_VER);
+ goto error;
+ }
+
+ VERBOSE("SCMI system power management protocol version 0x%x detected\n",
+ version);
+
+ INFO("SCMI driver initialized\n");
+
+ return (void *)ch;
+
+error:
+ ch->is_initialized = 0;
+ return NULL;
+}