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0537710040
Add Message Handling Unit (MHU) driver used to communicate among Application Processors (AP) and System Control Processor (SCP). Signed-off-by: Sumit Garg <sumit.garg@linaro.org>
95 lines
2.1 KiB
C
95 lines
2.1 KiB
C
/*
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* Copyright (c) 2018, ARM Limited and Contributors. All rights reserved.
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*
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* SPDX-License-Identifier: BSD-3-Clause
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*/
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#include <arch_helpers.h>
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#include <assert.h>
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#include <bakery_lock.h>
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#include <mmio.h>
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#include <platform_def.h>
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#include <sq_common.h>
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#include "sq_mhu.h"
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/* SCP MHU secure channel registers */
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#define SCP_INTR_S_STAT 0x200
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#define SCP_INTR_S_SET 0x208
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#define SCP_INTR_S_CLEAR 0x210
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/* CPU MHU secure channel registers */
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#define CPU_INTR_S_STAT 0x300
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#define CPU_INTR_S_SET 0x308
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#define CPU_INTR_S_CLEAR 0x310
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DEFINE_BAKERY_LOCK(sq_lock);
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/*
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* Slot 31 is reserved because the MHU hardware uses this register bit to
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* indicate a non-secure access attempt. The total number of available slots is
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* therefore 31 [30:0].
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*/
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#define MHU_MAX_SLOT_ID 30
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void mhu_secure_message_start(unsigned int slot_id)
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{
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assert(slot_id <= MHU_MAX_SLOT_ID);
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bakery_lock_get(&sq_lock);
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/* Make sure any previous command has finished */
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while (mmio_read_32(PLAT_SQ_MHU_BASE + CPU_INTR_S_STAT) &
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(1 << slot_id))
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;
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}
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void mhu_secure_message_send(unsigned int slot_id)
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{
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assert(slot_id <= MHU_MAX_SLOT_ID);
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assert(!(mmio_read_32(PLAT_SQ_MHU_BASE + CPU_INTR_S_STAT) &
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(1 << slot_id)));
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/* Send command to SCP */
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mmio_write_32(PLAT_SQ_MHU_BASE + CPU_INTR_S_SET, 1 << slot_id);
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}
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uint32_t mhu_secure_message_wait(void)
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{
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uint32_t response;
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/* Wait for response from SCP */
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while (!(response = mmio_read_32(PLAT_SQ_MHU_BASE + SCP_INTR_S_STAT)))
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;
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return response;
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}
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void mhu_secure_message_end(unsigned int slot_id)
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{
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assert(slot_id <= MHU_MAX_SLOT_ID);
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/*
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* Clear any response we got by writing one in the relevant slot bit to
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* the CLEAR register
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*/
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mmio_write_32(PLAT_SQ_MHU_BASE + SCP_INTR_S_CLEAR, 1 << slot_id);
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bakery_lock_release(&sq_lock);
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}
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void mhu_secure_init(void)
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{
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bakery_lock_init(&sq_lock);
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/*
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* The STAT register resets to zero. Ensure it is in the expected state,
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* as a stale or garbage value would make us think it's a message we've
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* already sent.
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*/
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assert(mmio_read_32(PLAT_SQ_MHU_BASE + CPU_INTR_S_STAT) == 0);
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}
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void plat_sq_pwrc_setup(void)
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{
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mhu_secure_init();
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}
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