Re: [PATCH v21 4/4] soc: mediatek: Add Mediatek CMDQ helper

[CK Hu]

Hi, Houlong:

I've some inline comment.

On Wed, 2018-01-31 at 15:28 +0800, houlong.wei@xxxxxxxxxxxx wrote:
> From: "hs.liao@xxxxxxxxxxxx" <hs.liao@xxxxxxxxxxxx>
> 
> Add Mediatek CMDQ helper to create CMDQ packet and assemble GCE op code.
> 
> Signed-off-by: Houlong Wei <houlong.wei@xxxxxxxxxxxx>
> Signed-off-by: HS Liao <hs.liao@xxxxxxxxxxxx>
> ---
>  drivers/soc/mediatek/Kconfig           |   12 ++
>  drivers/soc/mediatek/Makefile          |    1 +
>  drivers/soc/mediatek/mtk-cmdq-helper.c |  322 ++++++++++++++++++++++++++++++++
>  include/linux/soc/mediatek/mtk-cmdq.h  |  174 +++++++++++++++++
>  4 files changed, 509 insertions(+)
>  create mode 100644 drivers/soc/mediatek/mtk-cmdq-helper.c
>  create mode 100644 include/linux/soc/mediatek/mtk-cmdq.h
> 
> diff --git a/drivers/soc/mediatek/Kconfig b/drivers/soc/mediatek/Kconfig
> index a7d0667..e66582e 100644
> --- a/drivers/soc/mediatek/Kconfig
> +++ b/drivers/soc/mediatek/Kconfig
> @@ -4,6 +4,18 @@
>  menu "MediaTek SoC drivers"
>  	depends on ARCH_MEDIATEK || COMPILE_TEST
>  
> +config MTK_CMDQ
> +	bool "MediaTek CMDQ Support"
> +	depends on ARM64 && ( ARCH_MEDIATEK || COMPILE_TEST )
> +	select MAILBOX
> +	select MTK_CMDQ_MBOX
> +	select MTK_INFRACFG
> +	help
> +	  Say yes here to add support for the MediaTek Command Queue (CMDQ)
> +	  driver. The CMDQ is used to help read/write registers with critical
> +	  time limitation, such as updating display configuration during the
> +	  vblank.
> +
>  config MTK_INFRACFG
>  	bool "MediaTek INFRACFG Support"
>  	select REGMAP
> diff --git a/drivers/soc/mediatek/Makefile b/drivers/soc/mediatek/Makefile
> index 12998b0..64ce5ee 100644
> --- a/drivers/soc/mediatek/Makefile
> +++ b/drivers/soc/mediatek/Makefile
> @@ -1,3 +1,4 @@
> +obj-$(CONFIG_MTK_CMDQ) += mtk-cmdq-helper.o
>  obj-$(CONFIG_MTK_INFRACFG) += mtk-infracfg.o
>  obj-$(CONFIG_MTK_PMIC_WRAP) += mtk-pmic-wrap.o
>  obj-$(CONFIG_MTK_SCPSYS) += mtk-scpsys.o
> diff --git a/drivers/soc/mediatek/mtk-cmdq-helper.c b/drivers/soc/mediatek/mtk-cmdq-helper.c
> new file mode 100644
> index 0000000..80d0558
> --- /dev/null
> +++ b/drivers/soc/mediatek/mtk-cmdq-helper.c
> @@ -0,0 +1,322 @@
> +/*
> + * Copyright (c) 2015 MediaTek Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#include <linux/completion.h>
> +#include <linux/errno.h>
> +#include <linux/of_address.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/mailbox_controller.h>
> +#include <linux/soc/mediatek/mtk-cmdq.h>
> +
> +#define CMDQ_ARG_A_WRITE_MASK	0xffff
> +#define CMDQ_WRITE_ENABLE_MASK	BIT(0)
> +#define CMDQ_EOC_IRQ_EN		BIT(0)
> +#define CMDQ_EOC_CMD		((u64)((CMDQ_CODE_EOC << CMDQ_OP_CODE_SHIFT)) \
> +				<< 32 | CMDQ_EOC_IRQ_EN)
> +
> +struct cmdq_subsys {
> +	u32	base;
> +	int	id;
> +};
> +
> +static const struct cmdq_subsys gce_subsys[] = {
> +	{0x1400, 1},
> +	{0x1401, 2},
> +	{0x1402, 3},
> +};

I think subsys definition varies by different SoC, so it's better to
pass these definition from device tree to driver (client driver), and
client driver pass this subsys in the related interface. For example,

in include/dt-bindings/gce/mt8173-gce.h, you define

#define GCE_SUBSYS_1400XXXX		1
#define GCE_SUBSYS_1401XXXX		2
#define GCE_SUBSYS_1402XXXX		3

in device tree, place the subsys definition in client device node,

#include "dt-bindings/gce/mt8173-gce.h"

	ovl0: ovl@1400c000 {
		compatible = "mediatek,mt8173-disp-ovl";
		gce-subsys = <GCE_SUBSYS_1400XXXX>;
		...
	};

And client driver pass subsys in the related interface,

int cmdq_pkt_write(struct cmdq_pkt *pkt, u8 subsys, u16 offset, u32
value);

So, for another SoC, you just need to modify device tree and you do not
need to modify driver.

> +
> +static int cmdq_subsys_base_to_id(u32 base)
> +{
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(gce_subsys); i++)
> +		if (gce_subsys[i].base == base)
> +			return gce_subsys[i].id;
> +	return -EFAULT;
> +}
> +
> +static int cmdq_pkt_realloc_cmd_buffer(struct cmdq_pkt *pkt, size_t size)
> +{
> +	void *new_buf;
> +
> +	new_buf = krealloc(pkt->va_base, size, GFP_KERNEL | __GFP_ZERO);
> +	if (!new_buf)
> +		return -ENOMEM;
> +	pkt->va_base = new_buf;
> +	pkt->buf_size = size;
> +	return 0;
> +}
> +
> +struct cmdq_base *cmdq_register_device(struct device *dev)
> +{
> +	struct cmdq_base *cmdq_base;
> +	struct resource res;
> +	int subsys;
> +	u32 base;
> +
> +	if (of_address_to_resource(dev->of_node, 0, &res))
> +		return NULL;
> +	base = (u32)res.start;
> +
> +	subsys = cmdq_subsys_base_to_id(base >> 16);
> +	if (subsys < 0)
> +		return NULL;
> +
> +	cmdq_base = devm_kmalloc(dev, sizeof(*cmdq_base), GFP_KERNEL);
> +	if (!cmdq_base)
> +		return NULL;
> +	cmdq_base->subsys = subsys;
> +	cmdq_base->base = base;
> +
> +	return cmdq_base;
> +}
> +EXPORT_SYMBOL(cmdq_register_device);
> +
> +struct cmdq_client *cmdq_mbox_create(struct device *dev, int index)
> +{
> +	struct cmdq_client *client;
> +
> +	client = kzalloc(sizeof(*client), GFP_KERNEL);
> +	client->client.dev = dev;
> +	client->client.tx_block = false;
> +	client->chan = mbox_request_channel(&client->client, index);
> +	return client;
> +}
> +EXPORT_SYMBOL(cmdq_mbox_create);
> +
> +void cmdq_mbox_destroy(struct cmdq_client *client)
> +{
> +	mbox_free_channel(client->chan);
> +	kfree(client);
> +}
> +EXPORT_SYMBOL(cmdq_mbox_destroy);
> +
> +int cmdq_pkt_create(struct cmdq_pkt **pkt_ptr)
> +{
> +	struct cmdq_pkt *pkt;
> +	int err;
> +
> +	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
> +	if (!pkt)
> +		return -ENOMEM;
> +	err = cmdq_pkt_realloc_cmd_buffer(pkt, PAGE_SIZE);
> +	if (err < 0) {
> +		kfree(pkt);
> +		return err;
> +	}
> +	*pkt_ptr = pkt;
> +	return 0;
> +}
> +EXPORT_SYMBOL(cmdq_pkt_create);
> +
> +void cmdq_pkt_destroy(struct cmdq_pkt *pkt)
> +{
> +	kfree(pkt->va_base);
> +	kfree(pkt);
> +}
> +EXPORT_SYMBOL(cmdq_pkt_destroy);
> +
> +static bool cmdq_pkt_is_finalized(struct cmdq_pkt *pkt)
> +{
> +	u64 *expect_eoc;
> +
> +	if (pkt->cmd_buf_size < CMDQ_INST_SIZE << 1)
> +		return false;
> +
> +	expect_eoc = pkt->va_base + pkt->cmd_buf_size - (CMDQ_INST_SIZE << 1);
> +	if (*expect_eoc == CMDQ_EOC_CMD)
> +		return true;
> +
> +	return false;
> +}
> +
> +static int cmdq_pkt_append_command(struct cmdq_pkt *pkt, enum cmdq_code code,
> +				   u32 arg_a, u32 arg_b)
> +{
> +	u64 *cmd_ptr;
> +	int err;
> +
> +	if (WARN_ON(cmdq_pkt_is_finalized(pkt)))
> +		return -EBUSY;
> +	if (unlikely(pkt->cmd_buf_size + CMDQ_INST_SIZE > pkt->buf_size)) {
> +		err = cmdq_pkt_realloc_cmd_buffer(pkt, pkt->buf_size << 1);
> +		if (err < 0)
> +			return err;
> +	}
> +	cmd_ptr = pkt->va_base + pkt->cmd_buf_size;
> +	(*cmd_ptr) = (u64)((code << CMDQ_OP_CODE_SHIFT) | arg_a) << 32 | arg_b;
> +	pkt->cmd_buf_size += CMDQ_INST_SIZE;
> +	return 0;
> +}
> +
> +int cmdq_pkt_write(struct cmdq_pkt *pkt, u32 value, struct cmdq_base *base,
> +		   u32 offset)
> +{
> +	u32 arg_a = ((base->base + offset) & CMDQ_ARG_A_WRITE_MASK) |
> +		    (base->subsys << CMDQ_SUBSYS_SHIFT);
> +	return cmdq_pkt_append_command(pkt, CMDQ_CODE_WRITE, arg_a, value);
> +}
> +EXPORT_SYMBOL(cmdq_pkt_write);
> +
> +int cmdq_pkt_write_mask(struct cmdq_pkt *pkt, u32 value,
> +			struct cmdq_base *base, u32 offset, u32 mask)
> +{
> +	u32 offset_mask = offset;
> +	int err;
> +
> +	if (mask != 0xffffffff) {
> +		err = cmdq_pkt_append_command(pkt, CMDQ_CODE_MASK, 0, ~mask);
> +		if (err < 0)
> +			return err;
> +		offset_mask |= CMDQ_WRITE_ENABLE_MASK;
> +	}
> +	return cmdq_pkt_write(pkt, value, base, offset_mask);
> +}
> +EXPORT_SYMBOL(cmdq_pkt_write_mask);
> +
> +static const u32 cmdq_event_value[CMDQ_MAX_EVENT] = {
> +	/* Display start of frame(SOF) events */
> +	[CMDQ_EVENT_DISP_OVL0_SOF] = 11,
> +	[CMDQ_EVENT_DISP_OVL1_SOF] = 12,
> +	[CMDQ_EVENT_DISP_RDMA0_SOF] = 13,
> +	[CMDQ_EVENT_DISP_RDMA1_SOF] = 14,
> +	[CMDQ_EVENT_DISP_RDMA2_SOF] = 15,
> +	[CMDQ_EVENT_DISP_WDMA0_SOF] = 16,
> +	[CMDQ_EVENT_DISP_WDMA1_SOF] = 17,
> +	/* Display end of frame(EOF) events */
> +	[CMDQ_EVENT_DISP_OVL0_EOF] = 39,
> +	[CMDQ_EVENT_DISP_OVL1_EOF] = 40,
> +	[CMDQ_EVENT_DISP_RDMA0_EOF] = 41,
> +	[CMDQ_EVENT_DISP_RDMA1_EOF] = 42,
> +	[CMDQ_EVENT_DISP_RDMA2_EOF] = 43,
> +	[CMDQ_EVENT_DISP_WDMA0_EOF] = 44,
> +	[CMDQ_EVENT_DISP_WDMA1_EOF] = 45,
> +	/* Mutex end of frame(EOF) events */
> +	[CMDQ_EVENT_MUTEX0_STREAM_EOF] = 53,
> +	[CMDQ_EVENT_MUTEX1_STREAM_EOF] = 54,
> +	[CMDQ_EVENT_MUTEX2_STREAM_EOF] = 55,
> +	[CMDQ_EVENT_MUTEX3_STREAM_EOF] = 56,
> +	[CMDQ_EVENT_MUTEX4_STREAM_EOF] = 57,
> +	/* Display underrun events */
> +	[CMDQ_EVENT_DISP_RDMA0_UNDERRUN] = 63,
> +	[CMDQ_EVENT_DISP_RDMA1_UNDERRUN] = 64,
> +	[CMDQ_EVENT_DISP_RDMA2_UNDERRUN] = 65,
> +};

The event is like subsys that it varies by different SoC, so it's better
to pass this information from device tree to client driver. And the wait
for event interface would become

int cmdq_pkt_wfe(struct cmdq_pkt *pkt, u16 event)

And cmdq driver need not to translate the event value.

Regards,
CK

> +
> +int cmdq_pkt_wfe(struct cmdq_pkt *pkt, enum cmdq_event event)
> +{
> +	u32 arg_b;
> +
> +	if (event >= CMDQ_MAX_EVENT || event < 0)
> +		return -EINVAL;
> +
> +	/*
> +	 * WFE arg_b
> +	 * bit 0-11: wait value
> +	 * bit 15: 1 - wait, 0 - no wait
> +	 * bit 16-27: update value
> +	 * bit 31: 1 - update, 0 - no update
> +	 */
> +	arg_b = CMDQ_WFE_UPDATE | CMDQ_WFE_WAIT | CMDQ_WFE_WAIT_VALUE;
> +	return cmdq_pkt_append_command(pkt, CMDQ_CODE_WFE,
> +			cmdq_event_value[event], arg_b);
> +}
> +EXPORT_SYMBOL(cmdq_pkt_wfe);
> +
> +int cmdq_pkt_clear_event(struct cmdq_pkt *pkt, enum cmdq_event event)
> +{
> +	if (event >= CMDQ_MAX_EVENT || event < 0)
> +		return -EINVAL;
> +
> +	return cmdq_pkt_append_command(pkt, CMDQ_CODE_WFE,
> +			cmdq_event_value[event], CMDQ_WFE_UPDATE);
> +}
> +EXPORT_SYMBOL(cmdq_pkt_clear_event);
> +
> +static int cmdq_pkt_finalize(struct cmdq_pkt *pkt)
> +{
> +	int err;
> +
> +	if (cmdq_pkt_is_finalized(pkt))
> +		return 0;
> +
> +	/* insert EOC and generate IRQ for each command iteration */
> +	err = cmdq_pkt_append_command(pkt, CMDQ_CODE_EOC, 0, CMDQ_EOC_IRQ_EN);
> +	if (err < 0)
> +		return err;
> +
> +	/* JUMP to end */
> +	err = cmdq_pkt_append_command(pkt, CMDQ_CODE_JUMP, 0, CMDQ_JUMP_PASS);
> +	if (err < 0)
> +		return err;
> +
> +	return 0;
> +}
> +
> +int cmdq_pkt_flush_async(struct cmdq_client *client, struct cmdq_pkt *pkt,
> +			 cmdq_async_flush_cb cb, void *data)
> +{
> +	int err;
> +	struct device *dev;
> +	dma_addr_t dma_addr;
> +
> +	err = cmdq_pkt_finalize(pkt);
> +	if (err < 0)
> +		return err;
> +
> +	dev = client->chan->mbox->dev;
> +	dma_addr = dma_map_single(dev, pkt->va_base, pkt->cmd_buf_size,
> +		DMA_TO_DEVICE);
> +	if (dma_mapping_error(dev, dma_addr)) {
> +		dev_err(client->chan->mbox->dev, "dma map failed\n");
> +		return -ENOMEM;
> +	}
> +
> +	pkt->pa_base = dma_addr;
> +	pkt->cb.cb = cb;
> +	pkt->cb.data = data;
> +
> +	mbox_send_message(client->chan, pkt);
> +	/* We can send next packet immediately, so just call txdone. */
> +	mbox_client_txdone(client->chan, 0);
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(cmdq_pkt_flush_async);
> +
> +struct cmdq_flush_completion {
> +	struct completion cmplt;
> +	bool err;
> +};
> +
> +static void cmdq_pkt_flush_cb(struct cmdq_cb_data data)
> +{
> +	struct cmdq_flush_completion *cmplt = data.data;
> +
> +	cmplt->err = data.err;
> +	complete(&cmplt->cmplt);
> +}
> +
> +int cmdq_pkt_flush(struct cmdq_client *client, struct cmdq_pkt *pkt)
> +{
> +	struct cmdq_flush_completion cmplt;
> +	int err;
> +
> +	init_completion(&cmplt.cmplt);
> +	err = cmdq_pkt_flush_async(client, pkt, cmdq_pkt_flush_cb, &cmplt);
> +	if (err < 0)
> +		return err;
> +	wait_for_completion(&cmplt.cmplt);
> +	return cmplt.err ? -EFAULT : 0;
> +}
> +EXPORT_SYMBOL(cmdq_pkt_flush);
> diff --git a/include/linux/soc/mediatek/mtk-cmdq.h b/include/linux/soc/mediatek/mtk-cmdq.h
> new file mode 100644
> index 0000000..5b35d73
> --- /dev/null
> +++ b/include/linux/soc/mediatek/mtk-cmdq.h
> @@ -0,0 +1,174 @@
> +/*
> + * Copyright (c) 2015 MediaTek Inc.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + */
> +
> +#ifndef __MTK_CMDQ_H__
> +#define __MTK_CMDQ_H__
> +
> +#include <linux/mailbox_client.h>
> +#include <linux/mailbox/mtk-cmdq-mailbox.h>
> +
> +/* display events in command queue(CMDQ) */
> +enum cmdq_event {
> +	/* Display start of frame(SOF) events */
> +	CMDQ_EVENT_DISP_OVL0_SOF,
> +	CMDQ_EVENT_DISP_OVL1_SOF,
> +	CMDQ_EVENT_DISP_RDMA0_SOF,
> +	CMDQ_EVENT_DISP_RDMA1_SOF,
> +	CMDQ_EVENT_DISP_RDMA2_SOF,
> +	CMDQ_EVENT_DISP_WDMA0_SOF,
> +	CMDQ_EVENT_DISP_WDMA1_SOF,
> +	/* Display end of frame(EOF) events */
> +	CMDQ_EVENT_DISP_OVL0_EOF,
> +	CMDQ_EVENT_DISP_OVL1_EOF,
> +	CMDQ_EVENT_DISP_RDMA0_EOF,
> +	CMDQ_EVENT_DISP_RDMA1_EOF,
> +	CMDQ_EVENT_DISP_RDMA2_EOF,
> +	CMDQ_EVENT_DISP_WDMA0_EOF,
> +	CMDQ_EVENT_DISP_WDMA1_EOF,
> +	/* Mutex end of frame(EOF) events */
> +	CMDQ_EVENT_MUTEX0_STREAM_EOF,
> +	CMDQ_EVENT_MUTEX1_STREAM_EOF,
> +	CMDQ_EVENT_MUTEX2_STREAM_EOF,
> +	CMDQ_EVENT_MUTEX3_STREAM_EOF,
> +	CMDQ_EVENT_MUTEX4_STREAM_EOF,
> +	/* Display underrun events */
> +	CMDQ_EVENT_DISP_RDMA0_UNDERRUN,
> +	CMDQ_EVENT_DISP_RDMA1_UNDERRUN,
> +	CMDQ_EVENT_DISP_RDMA2_UNDERRUN,
> +	/* Keep this at the end */
> +	CMDQ_MAX_EVENT,
> +};
> +
> +struct cmdq_pkt;
> +
> +struct cmdq_base {
> +	int	subsys;
> +	u32	base;
> +};
> +
> +struct cmdq_client {
> +	struct mbox_client client;
> +	struct mbox_chan *chan;
> +};
> +
> +/**
> + * cmdq_register_device() - register device which needs CMDQ
> + * @dev:	device for CMDQ to access its registers
> + *
> + * Return: cmdq_base pointer or NULL for failed
> + */
> +struct cmdq_base *cmdq_register_device(struct device *dev);
> +
> +/**
> + * cmdq_mbox_create() - create CMDQ mailbox client and channel
> + * @dev:	device of CMDQ mailbox client
> + * @index:	index of CMDQ mailbox channel
> + *
> + * Return: CMDQ mailbox client pointer
> + */
> +struct cmdq_client *cmdq_mbox_create(struct device *dev, int index);
> +
> +/**
> + * cmdq_mbox_destroy() - destroy CMDQ mailbox client and channel
> + * @client:	the CMDQ mailbox client
> + */
> +void cmdq_mbox_destroy(struct cmdq_client *client);
> +
> +/**
> + * cmdq_pkt_create() - create a CMDQ packet
> + * @pkt_ptr:	CMDQ packet pointer to retrieve cmdq_pkt
> + *
> + * Return: 0 for success; else the error code is returned
> + */
> +int cmdq_pkt_create(struct cmdq_pkt **pkt_ptr);
> +
> +/**
> + * cmdq_pkt_destroy() - destroy the CMDQ packet
> + * @pkt:	the CMDQ packet
> + */
> +void cmdq_pkt_destroy(struct cmdq_pkt *pkt);
> +
> +/**
> + * cmdq_pkt_write() - append write command to the CMDQ packet
> + * @pkt:	the CMDQ packet
> + * @value:	the specified target register value
> + * @base:	the CMDQ base
> + * @offset:	register offset from module base
> + *
> + * Return: 0 for success; else the error code is returned
> + */
> +int cmdq_pkt_write(struct cmdq_pkt *pkt, u32 value,
> +		   struct cmdq_base *base, u32 offset);
> +
> +/**
> + * cmdq_pkt_write_mask() - append write command with mask to the CMDQ packet
> + * @pkt:	the CMDQ packet
> + * @value:	the specified target register value
> + * @base:	the CMDQ base
> + * @offset:	register offset from module base
> + * @mask:	the specified target register mask
> + *
> + * Return: 0 for success; else the error code is returned
> + */
> +int cmdq_pkt_write_mask(struct cmdq_pkt *pkt, u32 value,
> +			struct cmdq_base *base, u32 offset, u32 mask);
> +
> +/**
> + * cmdq_pkt_wfe() - append wait for event command to the CMDQ packet
> + * @pkt:	the CMDQ packet
> + * @event:	the desired event type to "wait and CLEAR"
> + *
> + * Return: 0 for success; else the error code is returned
> + */
> +int cmdq_pkt_wfe(struct cmdq_pkt *pkt, enum cmdq_event event);
> +
> +/**
> + * cmdq_pkt_clear_event() - append clear event command to the CMDQ packet
> + * @pkt:	the CMDQ packet
> + * @event:	the desired event to be cleared
> + *
> + * Return: 0 for success; else the error code is returned
> + */
> +int cmdq_pkt_clear_event(struct cmdq_pkt *pkt, enum cmdq_event event);
> +
> +/**
> + * cmdq_pkt_flush() - trigger CMDQ to execute the CMDQ packet
> + * @client:	the CMDQ mailbox client
> + * @pkt:	the CMDQ packet
> + *
> + * Return: 0 for success; else the error code is returned
> + *
> + * Trigger CMDQ to execute the CMDQ packet. Note that this is a
> + * synchronous flush function. When the function returned, the recorded
> + * commands have been done.
> + */
> +int cmdq_pkt_flush(struct cmdq_client *client, struct cmdq_pkt *pkt);
> +
> +/**
> + * cmdq_pkt_flush_async() - trigger CMDQ to asynchronously execute the CMDQ
> + *                          packet and call back at the end of done packet
> + * @client:	the CMDQ mailbox client
> + * @pkt:	the CMDQ packet
> + * @cb:		called at the end of done packet
> + * @data:	this data will pass back to cb
> + *
> + * Return: 0 for success; else the error code is returned
> + *
> + * Trigger CMDQ to asynchronously execute the CMDQ packet and call back
> + * at the end of done packet. Note that this is an ASYNC function. When the
> + * function returned, it may or may not be finished.
> + */
> +int cmdq_pkt_flush_async(struct cmdq_client *client, struct cmdq_pkt *pkt,
> +			 cmdq_async_flush_cb cb, void *data);
> +
> +#endif	/* __MTK_CMDQ_H__ */