Corstone700: add support for mhuv2 in arm TF-A
Note: This patch implements in-band messaging protocol only.
ARM has launched a next version of MHU i.e. MHUv2 with its latest
subsystems. The main change is that the MHUv2 is now a distributed IP
with different peripheral views (registers) for the sender and receiver.
Another main difference is that MHUv1 duplex channels are now split into
simplex/half duplex in MHUv2. MHUv2 has a configurable number of
communication channels. There is a capability register (MSG_NO_CAP) to
find out how many channels are available in a system.
The register offsets have also changed for STAT, SET & CLEAR registers
from 0x0, 0x8 & 0x10 in MHUv1 to 0x0, 0xC & 0x8 in MHUv2 respectively.
0x0 0x4 0x8 0xC 0x1F
------------------------....-----
| STAT | | | SET | | |
------------------------....-----
Transmit Channel
0x0 0x4 0x8 0xC 0x1F
------------------------....-----
| STAT | | CLR | | | |
------------------------....-----
Receive Channel
The MHU controller can request the receiver to wake-up and once the
request is removed, the receiver may go back to sleep, but the MHU
itself does not actively put a receiver to sleep.
So, in order to wake-up the receiver when the sender wants to send data,
the sender has to set ACCESS_REQUEST register first in order to wake-up
receiver, state of which can be detected using ACCESS_READY register.
ACCESS_REQUEST has an offset of 0xF88 & ACCESS_READY has an offset
of 0xF8C and are accessible only on any sender channel.
This patch adds necessary changes in a new file required to support the
latest MHUv2 controller. This patch also needs an update in DT binding
for ARM MHUv2 as we need a second register base (tx base) which would
be used as the send channel base.
Change-Id: I1455e08b3d88671a191c558790c503eabe07a8e6
Signed-off-by: Tushar Khandelwal <tushar.khandelwal@arm.com>
diff --git a/plat/arm/board/corstone700/drivers/mhu/mhu.c b/plat/arm/board/corstone700/drivers/mhu/mhu.c
new file mode 100644
index 0000000..2231d11
--- /dev/null
+++ b/plat/arm/board/corstone700/drivers/mhu/mhu.c
@@ -0,0 +1,117 @@
+/*
+ * Copyright (c) 2019-2020, 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 "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);
+}
diff --git a/plat/arm/board/corstone700/drivers/mhu/mhu.h b/plat/arm/board/corstone700/drivers/mhu/mhu.h
new file mode 100644
index 0000000..3808746
--- /dev/null
+++ b/plat/arm/board/corstone700/drivers/mhu/mhu.h
@@ -0,0 +1,37 @@
+/*
+ * Copyright (c) 2019-2020, ARM Limited. All rights reserved.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#ifndef MHU_H
+#define MHU_H
+
+#define MHU_POLL_INTR_STAT_TIMEOUT 50000 /*timeout value in us*/
+
+/* CPU MHU secure channel registers */
+#define CPU_INTR_S_STAT 0x00
+#define CPU_INTR_S_SET 0x0C
+
+/* MHUv2 Control Registers Offsets */
+#define MHU_V2_MSG_CFG_OFFSET 0xF80
+#define MHU_V2_ACCESS_REQ_OFFSET 0xF88
+#define MHU_V2_ACCESS_READY_OFFSET 0xF8C
+
+#define MHU_V2_ACCESS_REQUEST(addr) \
+ mmio_write_32((addr) + MHU_V2_ACCESS_REQ_OFFSET, 0x1)
+
+#define MHU_V2_CLEAR_REQUEST(addr) \
+ mmio_write_32((addr) + MHU_V2_ACCESS_REQ_OFFSET, 0x0)
+
+#define MHU_V2_IS_ACCESS_READY(addr) \
+ (mmio_read_32((addr) + MHU_V2_ACCESS_READY_OFFSET) & 0x1)
+
+void mhu_secure_message_start(uintptr_t address, unsigned int slot_id);
+void mhu_secure_message_send(uintptr_t address,
+ unsigned int slot_id,
+ unsigned int message);
+void mhu_secure_message_end(uintptr_t address, unsigned int slot_id);
+void mhu_secure_init(void);
+
+#endif /* MHU_H */