gxp-mailbox-driver.c - kernel/google-modules/gxp/zuma - Git at Google

 // SPDX-License-Identifier: GPL-2.0-only
 /*
  * GXP hardware-based mailbox driver implementation.
  *
  * Copyright (C) 2021 Google LLC
  */

 #include <asm/barrier.h>
 #include <linux/bitops.h>
 #include <linux/interrupt.h>
 #include <linux/kthread.h>
 #include <linux/of_irq.h>
 #include <linux/spinlock.h>

 #include "gxp-config.h" /* GXP_USE_LEGACY_MAILBOX */
 #include "gxp-mailbox-driver.h"
 #include "gxp-mailbox-regs.h"
 #include "gxp-mailbox.h"
 #include "gxp-pm.h"

 static u32 data_read(struct gxp_mailbox *mailbox, uint reg_offset)
 {
 	return readl(mailbox->data_reg_base + reg_offset);
 }

 static void data_write(struct gxp_mailbox *mailbox, uint reg_offset, u32 value)
 {
 	writel(value, mailbox->data_reg_base + reg_offset);
 }

 /* IRQ Handling */
 static irqreturn_t mailbox_irq_handler(int irq, void *arg)
 {
 	struct gxp_mailbox *mailbox = (struct gxp_mailbox *)arg;

 	gxp_mailbox_chip_irq_handler(mailbox);
 	return IRQ_HANDLED;
 }

 static void register_irq(struct gxp_mailbox *mailbox)
 {
 	int err;
 	unsigned int virq;

 	virq = irq_of_parse_and_map(mailbox->gxp->dev->of_node,
 				    mailbox->core_id);
 	if (!virq) {
 		pr_err("Unable to parse interrupt for core %d from the DT\n",
 		       mailbox->core_id);
 		return;
 	}

 	err = request_irq(virq, mailbox_irq_handler, /*flags=*/0,
 			  "aurora_mbx_irq", (void *)mailbox);
 	if (err) {
 		pr_err("Unable to register IRQ num=%d; error=%d\n", virq, err);
 		return;
 	}

 	mailbox->interrupt_virq = virq;
 	pr_debug("Core %d's mailbox interrupt registered as IRQ %u.\n",
 		 mailbox->core_id, virq);
 }

 static void unregister_irq(struct gxp_mailbox *mailbox)
 {
 	if (mailbox->interrupt_virq) {
 		pr_debug("Freeing IRQ %d\n", mailbox->interrupt_virq);
 		free_irq(mailbox->interrupt_virq, mailbox);
 		mailbox->interrupt_virq = 0;
 	}
 }

 /* gxp-mailbox-driver.h interface */

 u32 gxp_circ_queue_cnt(u32 head, u32 tail, u32 queue_size, u32 wrap_bit)
 {
 	if (CIRCULAR_QUEUE_WRAPPED(tail, wrap_bit) !=
 	    CIRCULAR_QUEUE_WRAPPED(head, wrap_bit))
 		return queue_size - CIRCULAR_QUEUE_REAL_INDEX(head, wrap_bit) +
 		       CIRCULAR_QUEUE_REAL_INDEX(tail, wrap_bit);
 	else
 		return tail - head;
 }

 u32 gxp_circ_queue_inc(u32 index, u32 inc, u32 queue_size, u32 wrap_bit)
 {
 	u32 new_index = CIRCULAR_QUEUE_REAL_INDEX(index, wrap_bit) + inc;

 	if (new_index >= queue_size)
 		return (index + inc - queue_size) ^ wrap_bit;
 	else
 		return index + inc;
 }

 void gxp_mailbox_driver_init(struct gxp_mailbox *mailbox)
 {
 	spin_lock_init(&mailbox->cmd_tail_resp_head_lock);
 	spin_lock_init(&mailbox->cmd_head_resp_tail_lock);
 }

 void gxp_mailbox_driver_exit(struct gxp_mailbox *mailbox)
 {
 	/* Nothing to cleanup */
 }

 void gxp_mailbox_driver_enable_interrupts(struct gxp_mailbox *mailbox)
 {
 	register_irq(mailbox);
 	gxp_mailbox_enable_interrupt(mailbox);
 }

 void gxp_mailbox_driver_disable_interrupts(struct gxp_mailbox *mailbox)
 {
 	unregister_irq(mailbox);
 }

 void __iomem *gxp_mailbox_get_csr_base(struct gxp_dev *gxp, uint index)
 {
 	return gxp->mbx[index].vaddr;
 }

 void __iomem *gxp_mailbox_get_data_base(struct gxp_dev *gxp, uint index)
 {
 	return gxp->mbx[index].vaddr + MBOX_DATA_REG_BASE;
 }

 /* gxp-mailbox-driver.h: Data register-based calls */

 void gxp_mailbox_write_status(struct gxp_mailbox *mailbox, u32 status)
 {
 	data_write(mailbox, MBOX_DATA_STATUS_OFFSET, status);
 }

 void gxp_mailbox_write_descriptor(struct gxp_mailbox *mailbox,
 				  dma_addr_t descriptor_addr)
 {
 	data_write(mailbox, MBOX_DATA_DESCRIPTOR_ADDR_OFFSET, (u32)descriptor_addr);
 }

 void gxp_mailbox_write_cmd_queue_tail(struct gxp_mailbox *mailbox, u16 val)
 {
 	u32 current_resp_head;
 	u32 new_cmd_tail;
 	unsigned long flags;

 	spin_lock_irqsave(&mailbox->cmd_tail_resp_head_lock, flags);

 	current_resp_head = data_read(mailbox, MBOX_DATA_CMD_TAIL_RESP_HEAD_OFFSET) &
 			    RESP_HEAD_MASK;
 	new_cmd_tail = (u32)val << CMD_TAIL_SHIFT;
 	data_write(mailbox, MBOX_DATA_CMD_TAIL_RESP_HEAD_OFFSET,
 		   new_cmd_tail | current_resp_head);

 	spin_unlock_irqrestore(&mailbox->cmd_tail_resp_head_lock, flags);
 }

 void gxp_mailbox_write_resp_queue_head(struct gxp_mailbox *mailbox, u16 val)
 {
 	u32 current_cmd_tail;
 	u32 new_resp_head;
 	unsigned long flags;

 	spin_lock_irqsave(&mailbox->cmd_tail_resp_head_lock, flags);

 	current_cmd_tail = data_read(mailbox, MBOX_DATA_CMD_TAIL_RESP_HEAD_OFFSET) &
 			   CMD_TAIL_MASK;
 	new_resp_head = (u32)val << RESP_HEAD_SHIFT;
 	data_write(mailbox, MBOX_DATA_CMD_TAIL_RESP_HEAD_OFFSET,
 		   current_cmd_tail | new_resp_head);

 	spin_unlock_irqrestore(&mailbox->cmd_tail_resp_head_lock, flags);
 }

 u16 gxp_mailbox_read_cmd_queue_head(struct gxp_mailbox *mailbox)
 {
 	u32 reg_val;
 	unsigned long flags;

 	spin_lock_irqsave(&mailbox->cmd_head_resp_tail_lock, flags);

 	reg_val = data_read(mailbox, MBOX_DATA_CMD_HEAD_RESP_TAIL_OFFSET);

 	spin_unlock_irqrestore(&mailbox->cmd_head_resp_tail_lock, flags);

 	return (u16)((reg_val & CMD_HEAD_MASK) >> CMD_HEAD_SHIFT);
 }

 u16 gxp_mailbox_read_resp_queue_tail(struct gxp_mailbox *mailbox)
 {
 	u32 reg_val;
 	unsigned long flags;

 	spin_lock_irqsave(&mailbox->cmd_head_resp_tail_lock, flags);

 	reg_val = data_read(mailbox, MBOX_DATA_CMD_HEAD_RESP_TAIL_OFFSET);

 	spin_unlock_irqrestore(&mailbox->cmd_head_resp_tail_lock, flags);

 	return (u16)((reg_val & RESP_TAIL_MASK) >> RESP_TAIL_SHIFT);
 }

 void gxp_mailbox_write_cmd_queue_head(struct gxp_mailbox *mailbox, u16 val)
 {
 	u32 current_resp_tail;
 	u32 new_cmd_head;
 	unsigned long flags;

 	spin_lock_irqsave(&mailbox->cmd_head_resp_tail_lock, flags);

 	current_resp_tail = data_read(mailbox, MBOX_DATA_CMD_HEAD_RESP_TAIL_OFFSET) &
 			    RESP_TAIL_MASK;
 	new_cmd_head = (u32)val << CMD_HEAD_SHIFT;
 	data_write(mailbox, MBOX_DATA_CMD_HEAD_RESP_TAIL_OFFSET,
 		   new_cmd_head | current_resp_tail);

 	spin_unlock_irqrestore(&mailbox->cmd_head_resp_tail_lock, flags);
 }

 void gxp_mailbox_write_resp_queue_tail(struct gxp_mailbox *mailbox, u16 val)
 {
 	u32 current_cmd_head;
 	u32 new_resp_tail;
 	unsigned long flags;

 	spin_lock_irqsave(&mailbox->cmd_head_resp_tail_lock, flags);

 	current_cmd_head = data_read(mailbox, MBOX_DATA_CMD_HEAD_RESP_TAIL_OFFSET) &
 			   CMD_HEAD_MASK;
 	new_resp_tail = (u32)val << RESP_TAIL_SHIFT;
 	data_write(mailbox, MBOX_DATA_CMD_HEAD_RESP_TAIL_OFFSET,
 		   current_cmd_head | new_resp_tail);

 	spin_unlock_irqrestore(&mailbox->cmd_head_resp_tail_lock, flags);
 }

 u16 gxp_mailbox_read_cmd_queue_tail(struct gxp_mailbox *mailbox)
 {
 	u32 reg_val;
 	unsigned long flags;

 	spin_lock_irqsave(&mailbox->cmd_tail_resp_head_lock, flags);

 	reg_val = data_read(mailbox, MBOX_DATA_CMD_TAIL_RESP_HEAD_OFFSET);

 	spin_unlock_irqrestore(&mailbox->cmd_tail_resp_head_lock, flags);

 	return (u16)((reg_val & CMD_TAIL_MASK) >> CMD_TAIL_SHIFT);
 }

 u16 gxp_mailbox_read_resp_queue_head(struct gxp_mailbox *mailbox)
 {
 	u32 reg_val;
 	unsigned long flags;

 	spin_lock_irqsave(&mailbox->cmd_tail_resp_head_lock, flags);

 	reg_val = data_read(mailbox, MBOX_DATA_CMD_TAIL_RESP_HEAD_OFFSET);

 	spin_unlock_irqrestore(&mailbox->cmd_tail_resp_head_lock, flags);

 	return (u16)((reg_val & RESP_HEAD_MASK) >> RESP_HEAD_SHIFT);
 }

 void gxp_mailbox_set_cmd_queue_tail(struct gxp_mailbox *mailbox, u32 value)
 {
 	mailbox->cmd_queue_tail = value;
 	gxp_mailbox_write_cmd_queue_tail(mailbox, value);
 }

 void gxp_mailbox_set_resp_queue_head(struct gxp_mailbox *mailbox, u32 value)
 {
 	mailbox->resp_queue_head = value;
 	gxp_mailbox_write_resp_queue_head(mailbox, value);
 }

 void gxp_mailbox_set_control(struct gxp_mailbox *mailbox, u32 val)
 {
 	data_write(mailbox, MBOX_DATA_CONTROL_OFFSET, val);
 }

 int gxp_mailbox_inc_cmd_queue_tail_nolock(struct gxp_mailbox *mailbox, u32 inc,
 					  u32 wrap_bit)
 {
 	u32 head;
 	u32 remain_size;
 	u32 new_tail;

 	if (inc > mailbox->cmd_queue_size)
 		return -EINVAL;

 	head = gxp_mailbox_read_cmd_queue_head(mailbox);
 	remain_size = mailbox->cmd_queue_size -
 		      gxp_circ_queue_cnt(head, mailbox->cmd_queue_tail,
 					 mailbox->cmd_queue_size, wrap_bit);
 	/* no enough space left */
 	if (inc > remain_size)
 		return -EBUSY;

 	new_tail = gxp_circ_queue_inc(mailbox->cmd_queue_tail, inc,
 				      mailbox->cmd_queue_size, wrap_bit);
 	gxp_mailbox_set_cmd_queue_tail(mailbox, new_tail);
 	return 0;
 }

 int gxp_mailbox_inc_cmd_queue_tail_locked(struct gxp_mailbox *mailbox, u32 inc,
 					  u32 wrap_bit)
 {
 	lockdep_assert_held(&mailbox->cmd_queue_lock);
 	return gxp_mailbox_inc_cmd_queue_tail_nolock(mailbox, inc, wrap_bit);
 }

 int gxp_mailbox_inc_resp_queue_head_nolock(struct gxp_mailbox *mailbox, u32 inc,
 					   u32 wrap_bit)
 {
 	u32 tail;
 	u32 size;
 	u32 new_head;

 	if (inc > mailbox->resp_queue_size)
 		return -EINVAL;

 	tail = gxp_mailbox_read_resp_queue_tail(mailbox);
 	size = gxp_circ_queue_cnt(mailbox->resp_queue_head, tail,
 				  mailbox->resp_queue_size, wrap_bit);
 	if (inc > size)
 		return -EINVAL;
 	new_head = gxp_circ_queue_inc(mailbox->resp_queue_head, inc,
 				      mailbox->resp_queue_size, wrap_bit);
 	gxp_mailbox_set_resp_queue_head(mailbox, new_head);

 	return 0;
 }

 int gxp_mailbox_inc_resp_queue_head_locked(struct gxp_mailbox *mailbox, u32 inc,
 					   u32 wrap_bit)
 {
 	lockdep_assert_held(&mailbox->resp_queue_lock);
 	return gxp_mailbox_inc_resp_queue_head_nolock(mailbox, inc, wrap_bit);
 }

 #if !GXP_USE_LEGACY_MAILBOX
 u32 gxp_mailbox_gcip_ops_get_cmd_queue_head(struct gcip_mailbox *mailbox)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	return gxp_mailbox_read_cmd_queue_head(gxp_mbx);
 }

 u32 gxp_mailbox_gcip_ops_get_cmd_queue_tail(struct gcip_mailbox *mailbox)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	return gxp_mbx->cmd_queue_tail;
 }

 void gxp_mailbox_gcip_ops_inc_cmd_queue_tail(struct gcip_mailbox *mailbox,
 					     u32 inc)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	lockdep_assert_held(&gxp_mbx->cmd_queue_lock);
 	gxp_mailbox_inc_cmd_queue_tail_nolock(gxp_mbx, inc,
 					      mailbox->queue_wrap_bit);
 }

 int gxp_mailbox_gcip_ops_acquire_cmd_queue_lock(struct gcip_mailbox *mailbox,
 						bool try, bool *atomic)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	mutex_lock(&gxp_mbx->cmd_queue_lock);
 	return 1;
 }

 void gxp_mailbox_gcip_ops_release_cmd_queue_lock(struct gcip_mailbox *mailbox)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	mutex_unlock(&gxp_mbx->cmd_queue_lock);
 }

 u32 gxp_mailbox_gcip_ops_get_resp_queue_size(struct gcip_mailbox *mailbox)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	return gxp_mbx->resp_queue_size;
 }

 u32 gxp_mailbox_gcip_ops_get_resp_queue_head(struct gcip_mailbox *mailbox)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	return gxp_mbx->resp_queue_head;
 }

 u32 gxp_mailbox_gcip_ops_get_resp_queue_tail(struct gcip_mailbox *mailbox)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	return gxp_mailbox_read_resp_queue_tail(gxp_mbx);
 }

 void gxp_mailbox_gcip_ops_inc_resp_queue_head(struct gcip_mailbox *mailbox,
 					       u32 inc)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	lockdep_assert_held(&gxp_mbx->resp_queue_lock);
 	gxp_mailbox_inc_resp_queue_head_nolock(gxp_mbx, inc,
 					       mailbox->queue_wrap_bit);
 }

 int gxp_mailbox_gcip_ops_acquire_resp_queue_lock(struct gcip_mailbox *mailbox,
 						 bool try, bool *atomic)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	*atomic = true;

 	if (try)
 		return spin_trylock_irqsave(&gxp_mbx->resp_queue_lock,
 					    gxp_mbx->resp_queue_lock_flags);

 	spin_lock_irqsave(&gxp_mbx->resp_queue_lock, gxp_mbx->resp_queue_lock_flags);
 	return 1;
 }

 void gxp_mailbox_gcip_ops_release_resp_queue_lock(struct gcip_mailbox *mailbox)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	spin_unlock_irqrestore(&gxp_mbx->resp_queue_lock, gxp_mbx->resp_queue_lock_flags);
 }

 void gxp_mailbox_gcip_ops_acquire_wait_list_lock(struct gcip_mailbox *mailbox,
 						 bool irqsave,
 						 unsigned long *flags)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	spin_lock_irqsave(&gxp_mbx->wait_list_lock, *flags);
 }

 void gxp_mailbox_gcip_ops_release_wait_list_lock(struct gcip_mailbox *mailbox,
 						 bool irqrestore,
 						 unsigned long flags)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	spin_unlock_irqrestore(&gxp_mbx->wait_list_lock, flags);
 }

 int gxp_mailbox_gcip_ops_wait_for_cmd_queue_not_full(
 	struct gcip_mailbox *mailbox)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;
 	u32 tail = gxp_mbx->cmd_queue_tail;

 	/*
 	 * If the cmd queue is full, it's up to the caller to retry.
 	 */
 	if (gxp_mailbox_read_cmd_queue_head(gxp_mbx) ==
 	    (tail ^ mailbox->queue_wrap_bit)) {
 		return -EAGAIN;
 	}

 	return 0;
 }

 int gxp_mailbox_gcip_ops_after_enqueue_cmd(struct gcip_mailbox *mailbox,
 					   void *cmd)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	/* triggers doorbell */
 	gxp_mailbox_generate_device_interrupt(gxp_mbx, BIT(0));

 	return 0;
 }

 void gxp_mailbox_gcip_ops_after_fetch_resps(struct gcip_mailbox *mailbox,
 					    u32 num_resps)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;
 	u32 size = gxp_mbx->resp_queue_size;

 	/*
 	 * Now that the response queue has been drained, send an interrupt
 	 * to the device in case firmware was waiting for us to consume
 	 * responses.
 	 */
 	if (num_resps == size)
 		gxp_mailbox_generate_device_interrupt(gxp_mbx, BIT(0));
 }

 bool gxp_mailbox_gcip_ops_is_block_off(struct gcip_mailbox *mailbox)
 {
 	struct gxp_mailbox *gxp_mbx = mailbox->data;

 	return gxp_pm_is_blk_down(gxp_mbx->gxp);
 }
 #endif /* !GXP_USE_LEGACY_MAILBOX */
	// SPDX-License-Identifier: GPL-2.0-only
	/*
	* GXP hardware-based mailbox driver implementation.
	*
	* Copyright (C) 2021 Google LLC
	*/

	#include <asm/barrier.h>
	#include <linux/bitops.h>
	#include <linux/interrupt.h>
	#include <linux/kthread.h>
	#include <linux/of_irq.h>
	#include <linux/spinlock.h>

	#include "gxp-config.h" /* GXP_USE_LEGACY_MAILBOX */
	#include "gxp-mailbox-driver.h"
	#include "gxp-mailbox-regs.h"
	#include "gxp-mailbox.h"
	#include "gxp-pm.h"

	static u32 data_read(struct gxp_mailbox *mailbox, uint reg_offset)
	{
	return readl(mailbox->data_reg_base + reg_offset);
	}

	static void data_write(struct gxp_mailbox *mailbox, uint reg_offset, u32 value)
	{
	writel(value, mailbox->data_reg_base + reg_offset);
	}

	/* IRQ Handling */
	static irqreturn_t mailbox_irq_handler(int irq, void *arg)
	{
	struct gxp_mailbox mailbox = (struct gxp_mailbox )arg;

	gxp_mailbox_chip_irq_handler(mailbox);
	return IRQ_HANDLED;
	}

	static void register_irq(struct gxp_mailbox *mailbox)
	{
	int err;
	unsigned int virq;

	virq = irq_of_parse_and_map(mailbox->gxp->dev->of_node,
	mailbox->core_id);
	if (!virq) {
	pr_err("Unable to parse interrupt for core %d from the DT\n",
	mailbox->core_id);
	return;
	}

	err = request_irq(virq, mailbox_irq_handler, /flags=/0,
	"aurora_mbx_irq", (void *)mailbox);
	if (err) {
	pr_err("Unable to register IRQ num=%d; error=%d\n", virq, err);
	return;
	}

	mailbox->interrupt_virq = virq;
	pr_debug("Core %d's mailbox interrupt registered as IRQ %u.\n",
	mailbox->core_id, virq);
	}

	static void unregister_irq(struct gxp_mailbox *mailbox)
	{
	if (mailbox->interrupt_virq) {
	pr_debug("Freeing IRQ %d\n", mailbox->interrupt_virq);
	free_irq(mailbox->interrupt_virq, mailbox);
	mailbox->interrupt_virq = 0;
	}
	}

	/* gxp-mailbox-driver.h interface */

	u32 gxp_circ_queue_cnt(u32 head, u32 tail, u32 queue_size, u32 wrap_bit)
	{
	if (CIRCULAR_QUEUE_WRAPPED(tail, wrap_bit) !=
	CIRCULAR_QUEUE_WRAPPED(head, wrap_bit))
	return queue_size - CIRCULAR_QUEUE_REAL_INDEX(head, wrap_bit) +
	CIRCULAR_QUEUE_REAL_INDEX(tail, wrap_bit);
	else
	return tail - head;
	}

	u32 gxp_circ_queue_inc(u32 index, u32 inc, u32 queue_size, u32 wrap_bit)
	{
	u32 new_index = CIRCULAR_QUEUE_REAL_INDEX(index, wrap_bit) + inc;

	if (new_index >= queue_size)
	return (index + inc - queue_size) ^ wrap_bit;
	else
	return index + inc;
	}

	void gxp_mailbox_driver_init(struct gxp_mailbox *mailbox)
	{
	spin_lock_init(&mailbox->cmd_tail_resp_head_lock);
	spin_lock_init(&mailbox->cmd_head_resp_tail_lock);
	}

	void gxp_mailbox_driver_exit(struct gxp_mailbox *mailbox)
	{
	/* Nothing to cleanup */
	}

	void gxp_mailbox_driver_enable_interrupts(struct gxp_mailbox *mailbox)
	{
	register_irq(mailbox);
	gxp_mailbox_enable_interrupt(mailbox);
	}

	void gxp_mailbox_driver_disable_interrupts(struct gxp_mailbox *mailbox)
	{
	unregister_irq(mailbox);
	}

	void __iomem gxp_mailbox_get_csr_base(struct gxp_dev gxp, uint index)
	{
	return gxp->mbx[index].vaddr;
	}

	void __iomem gxp_mailbox_get_data_base(struct gxp_dev gxp, uint index)
	{
	return gxp->mbx[index].vaddr + MBOX_DATA_REG_BASE;
	}

	/* gxp-mailbox-driver.h: Data register-based calls */

	void gxp_mailbox_write_status(struct gxp_mailbox *mailbox, u32 status)
	{
	data_write(mailbox, MBOX_DATA_STATUS_OFFSET, status);
	}

	void gxp_mailbox_write_descriptor(struct gxp_mailbox *mailbox,
	dma_addr_t descriptor_addr)
	{
	data_write(mailbox, MBOX_DATA_DESCRIPTOR_ADDR_OFFSET, (u32)descriptor_addr);
	}

	void gxp_mailbox_write_cmd_queue_tail(struct gxp_mailbox *mailbox, u16 val)
	{
	u32 current_resp_head;
	u32 new_cmd_tail;
	unsigned long flags;

	spin_lock_irqsave(&mailbox->cmd_tail_resp_head_lock, flags);

	current_resp_head = data_read(mailbox, MBOX_DATA_CMD_TAIL_RESP_HEAD_OFFSET) &
	RESP_HEAD_MASK;
	new_cmd_tail = (u32)val << CMD_TAIL_SHIFT;
	data_write(mailbox, MBOX_DATA_CMD_TAIL_RESP_HEAD_OFFSET,
	new_cmd_tail \| current_resp_head);

	spin_unlock_irqrestore(&mailbox->cmd_tail_resp_head_lock, flags);
	}

	void gxp_mailbox_write_resp_queue_head(struct gxp_mailbox *mailbox, u16 val)
	{
	u32 current_cmd_tail;
	u32 new_resp_head;
	unsigned long flags;

	spin_lock_irqsave(&mailbox->cmd_tail_resp_head_lock, flags);

	current_cmd_tail = data_read(mailbox, MBOX_DATA_CMD_TAIL_RESP_HEAD_OFFSET) &
	CMD_TAIL_MASK;
	new_resp_head = (u32)val << RESP_HEAD_SHIFT;
	data_write(mailbox, MBOX_DATA_CMD_TAIL_RESP_HEAD_OFFSET,
	current_cmd_tail \| new_resp_head);

	spin_unlock_irqrestore(&mailbox->cmd_tail_resp_head_lock, flags);
	}

	u16 gxp_mailbox_read_cmd_queue_head(struct gxp_mailbox *mailbox)
	{
	u32 reg_val;
	unsigned long flags;

	spin_lock_irqsave(&mailbox->cmd_head_resp_tail_lock, flags);

	reg_val = data_read(mailbox, MBOX_DATA_CMD_HEAD_RESP_TAIL_OFFSET);

	spin_unlock_irqrestore(&mailbox->cmd_head_resp_tail_lock, flags);

	return (u16)((reg_val & CMD_HEAD_MASK) >> CMD_HEAD_SHIFT);
	}

	u16 gxp_mailbox_read_resp_queue_tail(struct gxp_mailbox *mailbox)
	{
	u32 reg_val;
	unsigned long flags;

	spin_lock_irqsave(&mailbox->cmd_head_resp_tail_lock, flags);

	reg_val = data_read(mailbox, MBOX_DATA_CMD_HEAD_RESP_TAIL_OFFSET);

	spin_unlock_irqrestore(&mailbox->cmd_head_resp_tail_lock, flags);

	return (u16)((reg_val & RESP_TAIL_MASK) >> RESP_TAIL_SHIFT);
	}

	void gxp_mailbox_write_cmd_queue_head(struct gxp_mailbox *mailbox, u16 val)
	{
	u32 current_resp_tail;
	u32 new_cmd_head;
	unsigned long flags;

	spin_lock_irqsave(&mailbox->cmd_head_resp_tail_lock, flags);

	current_resp_tail = data_read(mailbox, MBOX_DATA_CMD_HEAD_RESP_TAIL_OFFSET) &
	RESP_TAIL_MASK;
	new_cmd_head = (u32)val << CMD_HEAD_SHIFT;
	data_write(mailbox, MBOX_DATA_CMD_HEAD_RESP_TAIL_OFFSET,
	new_cmd_head \| current_resp_tail);

	spin_unlock_irqrestore(&mailbox->cmd_head_resp_tail_lock, flags);
	}

	void gxp_mailbox_write_resp_queue_tail(struct gxp_mailbox *mailbox, u16 val)
	{
	u32 current_cmd_head;
	u32 new_resp_tail;
	unsigned long flags;

	spin_lock_irqsave(&mailbox->cmd_head_resp_tail_lock, flags);

	current_cmd_head = data_read(mailbox, MBOX_DATA_CMD_HEAD_RESP_TAIL_OFFSET) &
	CMD_HEAD_MASK;
	new_resp_tail = (u32)val << RESP_TAIL_SHIFT;
	data_write(mailbox, MBOX_DATA_CMD_HEAD_RESP_TAIL_OFFSET,
	current_cmd_head \| new_resp_tail);

	spin_unlock_irqrestore(&mailbox->cmd_head_resp_tail_lock, flags);
	}

	u16 gxp_mailbox_read_cmd_queue_tail(struct gxp_mailbox *mailbox)
	{
	u32 reg_val;
	unsigned long flags;

	spin_lock_irqsave(&mailbox->cmd_tail_resp_head_lock, flags);

	reg_val = data_read(mailbox, MBOX_DATA_CMD_TAIL_RESP_HEAD_OFFSET);

	spin_unlock_irqrestore(&mailbox->cmd_tail_resp_head_lock, flags);

	return (u16)((reg_val & CMD_TAIL_MASK) >> CMD_TAIL_SHIFT);
	}

	u16 gxp_mailbox_read_resp_queue_head(struct gxp_mailbox *mailbox)
	{
	u32 reg_val;
	unsigned long flags;

	spin_lock_irqsave(&mailbox->cmd_tail_resp_head_lock, flags);

	reg_val = data_read(mailbox, MBOX_DATA_CMD_TAIL_RESP_HEAD_OFFSET);

	spin_unlock_irqrestore(&mailbox->cmd_tail_resp_head_lock, flags);

	return (u16)((reg_val & RESP_HEAD_MASK) >> RESP_HEAD_SHIFT);
	}

	void gxp_mailbox_set_cmd_queue_tail(struct gxp_mailbox *mailbox, u32 value)
	{
	mailbox->cmd_queue_tail = value;
	gxp_mailbox_write_cmd_queue_tail(mailbox, value);
	}

	void gxp_mailbox_set_resp_queue_head(struct gxp_mailbox *mailbox, u32 value)
	{
	mailbox->resp_queue_head = value;
	gxp_mailbox_write_resp_queue_head(mailbox, value);
	}

	void gxp_mailbox_set_control(struct gxp_mailbox *mailbox, u32 val)
	{
	data_write(mailbox, MBOX_DATA_CONTROL_OFFSET, val);
	}

	int gxp_mailbox_inc_cmd_queue_tail_nolock(struct gxp_mailbox *mailbox, u32 inc,
	u32 wrap_bit)
	{
	u32 head;
	u32 remain_size;
	u32 new_tail;

	if (inc > mailbox->cmd_queue_size)
	return -EINVAL;

	head = gxp_mailbox_read_cmd_queue_head(mailbox);
	remain_size = mailbox->cmd_queue_size -
	gxp_circ_queue_cnt(head, mailbox->cmd_queue_tail,
	mailbox->cmd_queue_size, wrap_bit);
	/* no enough space left */
	if (inc > remain_size)
	return -EBUSY;

	new_tail = gxp_circ_queue_inc(mailbox->cmd_queue_tail, inc,
	mailbox->cmd_queue_size, wrap_bit);
	gxp_mailbox_set_cmd_queue_tail(mailbox, new_tail);
	return 0;
	}

	int gxp_mailbox_inc_cmd_queue_tail_locked(struct gxp_mailbox *mailbox, u32 inc,
	u32 wrap_bit)
	{
	lockdep_assert_held(&mailbox->cmd_queue_lock);
	return gxp_mailbox_inc_cmd_queue_tail_nolock(mailbox, inc, wrap_bit);
	}

	int gxp_mailbox_inc_resp_queue_head_nolock(struct gxp_mailbox *mailbox, u32 inc,
	u32 wrap_bit)
	{
	u32 tail;
	u32 size;
	u32 new_head;

	if (inc > mailbox->resp_queue_size)
	return -EINVAL;

	tail = gxp_mailbox_read_resp_queue_tail(mailbox);
	size = gxp_circ_queue_cnt(mailbox->resp_queue_head, tail,
	mailbox->resp_queue_size, wrap_bit);
	if (inc > size)
	return -EINVAL;
	new_head = gxp_circ_queue_inc(mailbox->resp_queue_head, inc,
	mailbox->resp_queue_size, wrap_bit);
	gxp_mailbox_set_resp_queue_head(mailbox, new_head);

	return 0;
	}

	int gxp_mailbox_inc_resp_queue_head_locked(struct gxp_mailbox *mailbox, u32 inc,
	u32 wrap_bit)
	{
	lockdep_assert_held(&mailbox->resp_queue_lock);
	return gxp_mailbox_inc_resp_queue_head_nolock(mailbox, inc, wrap_bit);
	}

	#if !GXP_USE_LEGACY_MAILBOX
	u32 gxp_mailbox_gcip_ops_get_cmd_queue_head(struct gcip_mailbox *mailbox)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	return gxp_mailbox_read_cmd_queue_head(gxp_mbx);
	}

	u32 gxp_mailbox_gcip_ops_get_cmd_queue_tail(struct gcip_mailbox *mailbox)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	return gxp_mbx->cmd_queue_tail;
	}

	void gxp_mailbox_gcip_ops_inc_cmd_queue_tail(struct gcip_mailbox *mailbox,
	u32 inc)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	lockdep_assert_held(&gxp_mbx->cmd_queue_lock);
	gxp_mailbox_inc_cmd_queue_tail_nolock(gxp_mbx, inc,
	mailbox->queue_wrap_bit);
	}

	int gxp_mailbox_gcip_ops_acquire_cmd_queue_lock(struct gcip_mailbox *mailbox,
	bool try, bool *atomic)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	mutex_lock(&gxp_mbx->cmd_queue_lock);
	return 1;
	}

	void gxp_mailbox_gcip_ops_release_cmd_queue_lock(struct gcip_mailbox *mailbox)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	mutex_unlock(&gxp_mbx->cmd_queue_lock);
	}

	u32 gxp_mailbox_gcip_ops_get_resp_queue_size(struct gcip_mailbox *mailbox)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	return gxp_mbx->resp_queue_size;
	}

	u32 gxp_mailbox_gcip_ops_get_resp_queue_head(struct gcip_mailbox *mailbox)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	return gxp_mbx->resp_queue_head;
	}

	u32 gxp_mailbox_gcip_ops_get_resp_queue_tail(struct gcip_mailbox *mailbox)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	return gxp_mailbox_read_resp_queue_tail(gxp_mbx);
	}

	void gxp_mailbox_gcip_ops_inc_resp_queue_head(struct gcip_mailbox *mailbox,
	u32 inc)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	lockdep_assert_held(&gxp_mbx->resp_queue_lock);
	gxp_mailbox_inc_resp_queue_head_nolock(gxp_mbx, inc,
	mailbox->queue_wrap_bit);
	}

	int gxp_mailbox_gcip_ops_acquire_resp_queue_lock(struct gcip_mailbox *mailbox,
	bool try, bool *atomic)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	*atomic = true;

	if (try)
	return spin_trylock_irqsave(&gxp_mbx->resp_queue_lock,
	gxp_mbx->resp_queue_lock_flags);

	spin_lock_irqsave(&gxp_mbx->resp_queue_lock, gxp_mbx->resp_queue_lock_flags);
	return 1;
	}

	void gxp_mailbox_gcip_ops_release_resp_queue_lock(struct gcip_mailbox *mailbox)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	spin_unlock_irqrestore(&gxp_mbx->resp_queue_lock, gxp_mbx->resp_queue_lock_flags);
	}

	void gxp_mailbox_gcip_ops_acquire_wait_list_lock(struct gcip_mailbox *mailbox,
	bool irqsave,
	unsigned long *flags)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	spin_lock_irqsave(&gxp_mbx->wait_list_lock, *flags);
	}

	void gxp_mailbox_gcip_ops_release_wait_list_lock(struct gcip_mailbox *mailbox,
	bool irqrestore,
	unsigned long flags)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	spin_unlock_irqrestore(&gxp_mbx->wait_list_lock, flags);
	}

	int gxp_mailbox_gcip_ops_wait_for_cmd_queue_not_full(
	struct gcip_mailbox *mailbox)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;
	u32 tail = gxp_mbx->cmd_queue_tail;

	/*
	* If the cmd queue is full, it's up to the caller to retry.
	*/
	if (gxp_mailbox_read_cmd_queue_head(gxp_mbx) ==
	(tail ^ mailbox->queue_wrap_bit)) {
	return -EAGAIN;
	}

	return 0;
	}

	int gxp_mailbox_gcip_ops_after_enqueue_cmd(struct gcip_mailbox *mailbox,
	void *cmd)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	/* triggers doorbell */
	gxp_mailbox_generate_device_interrupt(gxp_mbx, BIT(0));

	return 0;
	}

	void gxp_mailbox_gcip_ops_after_fetch_resps(struct gcip_mailbox *mailbox,
	u32 num_resps)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;
	u32 size = gxp_mbx->resp_queue_size;

	/*
	* Now that the response queue has been drained, send an interrupt
	* to the device in case firmware was waiting for us to consume
	* responses.
	*/
	if (num_resps == size)
	gxp_mailbox_generate_device_interrupt(gxp_mbx, BIT(0));
	}

	bool gxp_mailbox_gcip_ops_is_block_off(struct gcip_mailbox *mailbox)
	{
	struct gxp_mailbox *gxp_mbx = mailbox->data;

	return gxp_pm_is_blk_down(gxp_mbx->gxp);
	}
	#endif /* !GXP_USE_LEGACY_MAILBOX */