1 files changed, 117 insertions, 0 deletions
diff --git a/plat/arm/board/corstone700/common/drivers/mhu/corstone700_mhu.c b/plat/arm/board/corstone700/common/drivers/mhu/corstone700_mhu.c
new file mode 100644
index 0000000..832cfb7
--- /dev/null
+++ b/plat/arm/board/corstone700/common/drivers/mhu/corstone700_mhu.c
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2019-2022, Arm Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <arch_helpers.h>
+#include <common/debug.h>
+#include <drivers/delay_timer.h>
+#include <lib/bakery_lock.h>
+#include <lib/mmio.h>
+
+#include "corstone700_mhu.h"
+#include <plat_arm.h>
+#include <platform_def.h>
+
+ARM_INSTANTIATE_LOCK;
+
+#pragma weak plat_arm_pwrc_setup
+
+/*
+ * Slot 31 is reserved because the MHU hardware uses this register bit to
+ * indicate a non-secure access attempt. The total number of available slots is
+ * therefore 31 [30:0].
+ */
+#define MHU_MAX_SLOT_ID		30
+
+void mhu_secure_message_start(uintptr_t address, unsigned int slot_id)
+{
+	unsigned int intr_stat_check;
+	uint64_t timeout_cnt;
+	volatile uint8_t expiration;
+
+	assert(slot_id <= MHU_MAX_SLOT_ID);
+	arm_lock_get();
+
+	/*
+	 * Make sure any previous command has finished
+	 * and polling timeout not expired
+	 */
+
+	timeout_cnt = timeout_init_us(MHU_POLL_INTR_STAT_TIMEOUT);
+
+	do {
+		intr_stat_check = (mmio_read_32(address + CPU_INTR_S_STAT) &
+						(1 << slot_id));
+
+		expiration = timeout_elapsed(timeout_cnt);
+
+	} while ((intr_stat_check != 0U) && (expiration == 0U));
+
+	/*
+	 * Note: No risk of timer overflows while waiting
+	 * for the timeout expiration.
+	 * According to Armv8 TRM: System counter roll-over
+	 * time of not less than 40 years
+	 */
+}
+
+void mhu_secure_message_send(uintptr_t address,
+				unsigned int slot_id,
+				unsigned int message)
+{
+	unsigned char access_ready;
+	uint64_t timeout_cnt;
+	volatile uint8_t expiration;
+
+	assert(slot_id <= MHU_MAX_SLOT_ID);
+	assert((mmio_read_32(address + CPU_INTR_S_STAT) &
+						(1 << slot_id)) == 0U);
+
+	MHU_V2_ACCESS_REQUEST(address);
+
+	timeout_cnt = timeout_init_us(MHU_POLL_INTR_STAT_TIMEOUT);
+
+	do {
+		access_ready = MHU_V2_IS_ACCESS_READY(address);
+		expiration = timeout_elapsed(timeout_cnt);
+
+	} while ((access_ready == 0U) && (expiration == 0U));
+
+	/*
+	 * Note: No risk of timer overflows while waiting
+	 * for the timeout expiration.
+	 * According to Armv8 TRM: System counter roll-over
+	 * time of not less than 40 years
+	 */
+
+	mmio_write_32(address + CPU_INTR_S_SET, message);
+}
+
+void mhu_secure_message_end(uintptr_t address, unsigned int slot_id)
+{
+	assert(slot_id <= MHU_MAX_SLOT_ID);
+	/*
+	 * Clear any response we got by writing one in the relevant slot bit to
+	 * the CLEAR register
+	 */
+	MHU_V2_CLEAR_REQUEST(address);
+
+	arm_lock_release();
+}
+
+void __init mhu_secure_init(void)
+{
+	arm_lock_init();
+
+	/*
+	 * The STAT register resets to zero. Ensure it is in the expected state,
+	 * as a stale or garbage value would make us think it's a message we've
+	 * already sent.
+	 */
+
+	assert(mmio_read_32(PLAT_SDK700_MHU0_SEND + CPU_INTR_S_STAT) == 0);
+}