Re: [PATCH v23 4/4] soc: mediatek: Add Mediatek CMDQ helper

From: Matthias Brugger
Date: Wed Sep 26 2018 - 11:53:49 EST




On 25/07/2018 03:26, Houlong Wei wrote:
> 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 | 291 ++++++++++++++++++++++++++++++++
> include/linux/soc/mediatek/mtk-cmdq.h | 135 +++++++++++++++
> 4 files changed, 439 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..17bd759 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
> + tristate "MediaTek CMDQ Support"
> + depends on 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..e4dbb7e
> --- /dev/null
> +++ b/drivers/soc/mediatek/mtk-cmdq-helper.c
> @@ -0,0 +1,291 @@
> +// SPDX-License-Identifier: GPL-2.0
> +//
> +// Copyright (c) 2018 MediaTek Inc.
> +
> +#include <linux/completion.h>
> +#include <linux/errno.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)
> +
> +static void cmdq_client_timeout(struct timer_list *t)
> +{
> + struct cmdq_client *client = from_timer(client, t, timer);
> +
> + dev_err(client->client.dev, "cmdq timeout!\n");
> +}
> +
> +struct cmdq_client *cmdq_mbox_create(struct device *dev, int index, u32 timeout)
> +{
> + struct cmdq_client *client;
> +
> + client = kzalloc(sizeof(*client), GFP_KERNEL);
> + if (!client)
> + return (struct cmdq_client *)-ENOMEM;
> +
> + client->timeout_ms = timeout;
> + if (timeout != CMDQ_NO_TIMEOUT) {
> + spin_lock_init(&client->lock);
> + timer_setup(&client->timer, cmdq_client_timeout, 0);
> + }
> + client->pkt_cnt = 0;
> + client->client.dev = dev;
> + client->client.tx_block = false;
> + client->chan = mbox_request_channel(&client->client, index);
> +
> + if (IS_ERR(client->chan)) {
> + long err = 0;
> +
> + dev_err(dev, "failed to request channel\n");
> + err = PTR_ERR(client->chan);
> + kfree(client);
> +
> + return (struct cmdq_client *)err;

Can't we use
return ERR_PTR(err);
here?

> + }
> +
> + return client;
> +}
> +EXPORT_SYMBOL(cmdq_mbox_create);
> +
> +void cmdq_mbox_destroy(struct cmdq_client *client)
> +{
> + if (client->timeout_ms != CMDQ_NO_TIMEOUT) {
> + spin_lock(&client->lock);
> + del_timer_sync(&client->timer);
> + spin_unlock(&client->lock);
> + }
> + mbox_free_channel(client->chan);
> + kfree(client);
> +}
> +EXPORT_SYMBOL(cmdq_mbox_destroy);
> +
> +int cmdq_pkt_create(struct cmdq_client *client, struct cmdq_pkt **pkt_ptr,
> + size_t size)

I suppose you are not returning the allocated cmdq_pkt to avoid checks for
IS_ERR() logic in the consumer of this API. Am I correct?
Do we really need a pointer to a pointer here? Can't we just use a struct
cmdq_pkt *pkt as argument? That would make things easier.

> +{
> + struct cmdq_pkt *pkt;
> + struct device *dev;
> + dma_addr_t dma_addr;
> +
> + pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
> + if (!pkt)
> + return -ENOMEM;
> + pkt->va_base = kzalloc(size, GFP_KERNEL);
> + if (!pkt->va_base) {
> + kfree(pkt);
> + return -ENOMEM;
> + }
> + pkt->buf_size = size;
> + pkt->cl = (void *)client;
> +
> + dev = client->chan->mbox->dev;
> + dma_addr = dma_map_single(dev, pkt->va_base, pkt->buf_size,
> + DMA_TO_DEVICE);
> + if (dma_mapping_error(dev, dma_addr)) {
> + dev_err(dev, "dma map failed, size=%u\n", (u32)(u64)size);
> + kfree(pkt->va_base);
> + kfree(pkt);
> + return -ENOMEM;
> + }
> +
> + pkt->pa_base = dma_addr;
> + *pkt_ptr = pkt;
> +
> + return 0;
> +}
> +EXPORT_SYMBOL(cmdq_pkt_create);
> +
> +void cmdq_pkt_destroy(struct cmdq_pkt *pkt)
> +{
> + struct cmdq_client *client = (struct cmdq_client *)pkt->cl;
> +
> + dma_unmap_single(client->chan->mbox->dev, pkt->pa_base, pkt->buf_size,
> + DMA_TO_DEVICE);
> + kfree(pkt->va_base);
> + kfree(pkt);
> +}
> +EXPORT_SYMBOL(cmdq_pkt_destroy);
> +
> +static int cmdq_pkt_append_command(struct cmdq_pkt *pkt, enum cmdq_code code,
> + u32 arg_a, u32 arg_b)
> +{
> + u64 *cmd_ptr;
> +
> + if (unlikely(pkt->cmd_buf_size + CMDQ_INST_SIZE > pkt->buf_size)) {
> + pkt->cmd_buf_size += CMDQ_INST_SIZE;

Why do we update the cmd_buf_size here?

> + return -ENOMEM;
> + }
> + 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, u32 subsys, u32 offset)
> +{
> + u32 arg_a = (offset & CMDQ_ARG_A_WRITE_MASK) |
> + (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,
> + u32 subsys, u32 offset, u32 mask)
> +{
> + u32 offset_mask = offset;
> + int err;
> +
> + if (mask != 0xffffffff) {
> + err = cmdq_pkt_append_command(pkt, CMDQ_CODE_MASK, 0, ~mask);
> + WARN_ON(err < 0);
> + offset_mask |= CMDQ_WRITE_ENABLE_MASK;
> + }
> +
> + return cmdq_pkt_write(pkt, value, subsys, offset_mask);
> +}
> +EXPORT_SYMBOL(cmdq_pkt_write_mask);
> +
> +int cmdq_pkt_wfe(struct cmdq_pkt *pkt, u32 event)
> +{
> + u32 arg_b;
> +
> + if (event >= CMDQ_MAX_EVENT)
> + 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, event, arg_b);
> +}
> +EXPORT_SYMBOL(cmdq_pkt_wfe);
> +
> +int cmdq_pkt_clear_event(struct cmdq_pkt *pkt, u32 event)
> +{
> + if (event >= CMDQ_MAX_EVENT)
> + return -EINVAL;
> +
> + return cmdq_pkt_append_command(pkt, CMDQ_CODE_WFE, event,
> + CMDQ_WFE_UPDATE);
> +}
> +EXPORT_SYMBOL(cmdq_pkt_clear_event);
> +
> +static int cmdq_pkt_finalize(struct cmdq_pkt *pkt)
> +{
> + int err;
> +
> + /* insert EOC and generate IRQ for each command iteration */
> + err = cmdq_pkt_append_command(pkt, CMDQ_CODE_EOC, 0, CMDQ_EOC_IRQ_EN);
> + WARN_ON(err < 0);
> +
> + /* JUMP to end */
> + err = cmdq_pkt_append_command(pkt, CMDQ_CODE_JUMP, 0, CMDQ_JUMP_PASS);
> + WARN_ON(err < 0);
> +
> + return err;
> +}
> +
> +static void cmdq_pkt_flush_async_cb(struct cmdq_cb_data data)
> +{
> + struct cmdq_pkt *pkt = (struct cmdq_pkt *)data.data;
> + struct cmdq_task_cb *cb = &pkt->cb;
> + struct cmdq_client *client = (struct cmdq_client *)pkt->cl;
> +
> + if (client->timeout_ms != CMDQ_NO_TIMEOUT) {
> + unsigned long flags = 0;
> +
> + spin_lock_irqsave(&client->lock, flags);
> + if (--client->pkt_cnt == 0)
> + del_timer(&client->timer);
> + else
> + mod_timer(&client->timer, jiffies +
> + msecs_to_jiffies(client->timeout_ms));
> + spin_unlock_irqrestore(&client->lock, flags);
> + }> +
> + dma_sync_single_for_cpu(client->chan->mbox->dev, pkt->pa_base,
> + pkt->cmd_buf_size, DMA_TO_DEVICE);
> + if (cb->cb) {
> + data.data = cb->data;
> + cb->cb(data);
> + }
> +}
> +
> +int cmdq_pkt_flush_async(struct cmdq_pkt *pkt, cmdq_async_flush_cb cb,
> + void *data)
> +{
> + int err;
> + unsigned long flags = 0;
> + struct cmdq_client *client = (struct cmdq_client *)pkt->cl;
> +
> + err = cmdq_pkt_finalize(pkt);
> + if (err < 0)
> + return err;
> +
> + pkt->cb.cb = cb;
> + pkt->cb.data = data;
> + pkt->async_cb.cb = cmdq_pkt_flush_async_cb;
> + pkt->async_cb.data = pkt;
> +
> + dma_sync_single_for_device(client->chan->mbox->dev, pkt->pa_base,
> + pkt->cmd_buf_size, DMA_TO_DEVICE);
> +
> + if (client->timeout_ms != CMDQ_NO_TIMEOUT) {
> + spin_lock_irqsave(&client->lock, flags);
> + if (client->pkt_cnt++ == 0)
> + mod_timer(&client->timer, jiffies +
> + msecs_to_jiffies(client->timeout_ms));
> + spin_unlock_irqrestore(&client->lock, flags);
> + }
> +
> + 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;
> +
> + cmplt = (struct cmdq_flush_completion *)data.data;
> + if (data.sta != CMDQ_CB_NORMAL)
> + cmplt->err = true;
> + else
> + cmplt->err = false;
> + complete(&cmplt->cmplt);
> +}
> +
> +int cmdq_pkt_flush(struct cmdq_pkt *pkt)
> +{
> + struct cmdq_flush_completion cmplt;
> + int err;
> +
> + init_completion(&cmplt.cmplt);
> + err = cmdq_pkt_flush_async(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..fc84fe4
> --- /dev/null
> +++ b/include/linux/soc/mediatek/mtk-cmdq.h
> @@ -0,0 +1,135 @@
> +/* SPDX-License-Identifier: GPL-2.0 */
> +/*
> + * Copyright (c) 2018 MediaTek Inc.
> + *
> + */
> +
> +#ifndef __MTK_CMDQ_H__
> +#define __MTK_CMDQ_H__
> +
> +#include <linux/mailbox_client.h>
> +#include <linux/mailbox/mtk-cmdq-mailbox.h>
> +#include <linux/timer.h>
> +
> +#define CMDQ_NO_TIMEOUT 0xffffffffu
> +
> +/** cmdq event maximum */
> +#define CMDQ_MAX_EVENT 0x3ff
> +
> +struct cmdq_pkt;
> +
> +struct cmdq_client {
> + spinlock_t lock;
> + u32 pkt_cnt;
> + struct mbox_client client;
> + struct mbox_chan *chan;
> + struct timer_list timer;
> + u32 timeout_ms; /* in unit of microsecond */
> +};
> +
> +/**
> + * cmdq_mbox_create() - create CMDQ mailbox client and channel
> + * @dev: device of CMDQ mailbox client
> + * @index: index of CMDQ mailbox channel
> + * @timeout: timeout of a pkt execution by GCE, in unit of microsecond, set
> + * CMDQ_NO_TIMEOUT if a timer is not used.
> + *
> + * Return: CMDQ mailbox client pointer
> + */
> +struct cmdq_client *cmdq_mbox_create(struct device *dev, int index,
> + u32 timeout);
> +
> +/**
> + * 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
> + * @client: the CMDQ mailbox client
> + * @pkt_ptr: CMDQ packet pointer to retrieve cmdq_pkt
> + * @size: CMDQ buffer size
> + *
> + * Return: 0 for success; else the error code is returned
> + */
> +int cmdq_pkt_create(struct cmdq_client *client, struct cmdq_pkt **pkt_ptr,
> + size_t size);
> +
> +/**
> + * 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
> + * @subsys: the CMDQ sub system code
> + * @offset: register offset from CMDQ sub system
> + *
> + * Return: 0 for success; else the error code is returned
> + */
> +int cmdq_pkt_write(struct cmdq_pkt *pkt, u32 value, u32 subsys, 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
> + * @subsys: the CMDQ sub system code
> + * @offset: register offset from CMDQ sub system
> + * @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,
> + u32 subsys, 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, u32 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, u32 event);
> +
> +/**
> + * cmdq_pkt_flush() - trigger CMDQ to execute the CMDQ packet
> + * @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_pkt *pkt);
> +
> +/**
> + * cmdq_pkt_flush_async() - trigger CMDQ to asynchronously execute the CMDQ
> + * packet and call back at the end of done packet
> + * @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_pkt *pkt, cmdq_async_flush_cb cb,
> + void *data);
> +

bikeshadding alarm:
can we order the functions in the include file the same way we do in the c file?

Apart from the few comments, the driver looks fine to me.

Regards,
Matthias