Re: [PATCH v8 2/3] CMDQ: Mediatek CMDQ driver

CK Hu
2016-05-30T06:49:02Z

Hi, HS:

Some comments inline.

On Mon, 2016-05-30 at 11:19 +0800, HS Liao wrote:
> This patch is first version of 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. It controls
> Global Command Engine (GCE) hardware to achieve this requirement.
> Currently, CMDQ only supports display related hardwares, but we expect
> it can be extended to other hardwares for future requirements.
>
> Signed-off-by: HS Liao <hs.liao@mediatek.com>
> Signed-off-by: CK Hu <ck.hu@mediatek.com>
> ---
> drivers/soc/mediatek/Kconfig | 10 +
> drivers/soc/mediatek/Makefile | 1 +
> drivers/soc/mediatek/mtk-cmdq.c | 943 ++++++++++++++++++++++++++++++++++++++++
> include/soc/mediatek/cmdq.h | 197 +++++++++
> 4 files changed, 1151 insertions(+)
> create mode 100644 drivers/soc/mediatek/mtk-cmdq.c
> create mode 100644 include/soc/mediatek/cmdq.h
>
> diff --git a/drivers/soc/mediatek/Kconfig b/drivers/soc/mediatek/Kconfig
> index 0a4ea80..c4ad75c 100644
> --- a/drivers/soc/mediatek/Kconfig
> +++ b/drivers/soc/mediatek/Kconfig
> @@ -1,6 +1,16 @@
> #
> # MediaTek SoC drivers
> #
> +config MTK_CMDQ
> + bool "MediaTek CMDQ Support"
> + depends on ARCH_MEDIATEK || COMPILE_TEST
> + 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"
> depends on ARCH_MEDIATEK || COMPILE_TEST
> diff --git a/drivers/soc/mediatek/Makefile b/drivers/soc/mediatek/Makefile
> index 12998b0..f7397ef 100644
> --- a/drivers/soc/mediatek/Makefile
> +++ b/drivers/soc/mediatek/Makefile
> @@ -1,3 +1,4 @@
> +obj-$(CONFIG_MTK_CMDQ) += mtk-cmdq.o
> obj-$(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.c b/drivers/soc/mediatek/mtk-cmdq.c
> new file mode 100644
> index 0000000..e9d6e1c
> --- /dev/null
> +++ b/drivers/soc/mediatek/mtk-cmdq.c
> @@ -0,0 +1,943 @@
> +/*
> + * 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/clk.h>
> +#include <linux/clk-provider.h>
> +#include <linux/completion.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/errno.h>
> +#include <linux/interrupt.h>
> +#include <linux/iopoll.h>
> +#include <linux/kernel.h>
> +#include <linux/kthread.h>
> +#include <linux/module.h>
> +#include <linux/mutex.h>
> +#include <linux/of_address.h>
> +#include <linux/of_irq.h>
> +#include <linux/platform_device.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +#include <linux/suspend.h>
> +#include <linux/workqueue.h>
> +#include <soc/mediatek/cmdq.h>
> +
> +#define CMDQ_INITIAL_CMD_BLOCK_SIZE PAGE_SIZE
> +#define CMDQ_INST_SIZE 8 /* instruction is 64-bit */
> +#define CMDQ_TIMEOUT_MS 1000
> +#define CMDQ_IRQ_MASK 0xffff
> +#define CMDQ_DRIVER_DEVICE_NAME "mtk_cmdq"
> +#define CMDQ_CLK_NAME "gce"
> +
> +#define CMDQ_CURR_IRQ_STATUS 0x010
> +#define CMDQ_CURR_LOADED_THR 0x018
> +#define CMDQ_THR_SLOT_CYCLES 0x030
> +
> +#define CMDQ_THR_BASE 0x100
> +#define CMDQ_THR_SHIFT 0x080
> +#define CMDQ_THR_WARM_RESET 0x00
> +#define CMDQ_THR_ENABLE_TASK 0x04
> +#define CMDQ_THR_SUSPEND_TASK 0x08
> +#define CMDQ_THR_CURR_STATUS 0x0c
> +#define CMDQ_THR_IRQ_STATUS 0x10
> +#define CMDQ_THR_IRQ_ENABLE 0x14
> +#define CMDQ_THR_CURR_ADDR 0x20
> +#define CMDQ_THR_END_ADDR 0x24
> +#define CMDQ_THR_CFG 0x40
> +
> +#define CMDQ_THR_ENABLED 0x1
> +#define CMDQ_THR_DISABLED 0x0
> +#define CMDQ_THR_SUSPEND 0x1
> +#define CMDQ_THR_RESUME 0x0
> +#define CMDQ_THR_STATUS_SUSPENDED BIT(1)
> +#define CMDQ_THR_DO_WARM_RESET BIT(0)
> +#define CMDQ_THR_ACTIVE_SLOT_CYCLES 0x3200
> +#define CMDQ_THR_PRIORITY 3
> +#define CMDQ_THR_IRQ_DONE 0x1
> +#define CMDQ_THR_IRQ_ERROR 0x12
> +#define CMDQ_THR_IRQ_EN 0x13 /* done + error */
> +#define CMDQ_THR_IRQ_MASK 0x13
> +#define CMDQ_THR_EXECUTING BIT(31)
> +
> +#define CMDQ_ARG_A_WRITE_MASK 0xffff
> +#define CMDQ_SUBSYS_MASK 0x1f
> +#define CMDQ_OP_CODE_MASK 0xff000000
> +
> +#define CMDQ_OP_CODE_SHIFT 24
> +#define CMDQ_SUBSYS_SHIFT 16
> +
> +#define CMDQ_WRITE_ENABLE_MASK BIT(0)
> +#define CMDQ_JUMP_BY_OFFSET 0x10000000
> +#define CMDQ_JUMP_BY_PA 0x10000001
> +#define CMDQ_JUMP_PASS CMDQ_INST_SIZE
> +#define CMDQ_WFE_UPDATE BIT(31)
> +#define CMDQ_WFE_WAIT BIT(15)
> +#define CMDQ_WFE_WAIT_VALUE 0x1
> +#define CMDQ_EOC_IRQ_EN BIT(0)
> +
> +enum cmdq_thread_index {
> + CMDQ_THR_DISP_MAIN_IDX, /* main */
> + CMDQ_THR_DISP_SUB_IDX, /* sub */
> + CMDQ_THR_DISP_MISC_IDX, /* misc */
> + CMDQ_THR_MAX_COUNT, /* max */
> +};
> +
> +/*
> + * CMDQ_CODE_MOVE:
> + * move value into internal register as mask
> + * format: op mask
> + * CMDQ_CODE_WRITE:
> + * write value into target register
> + * format: op subsys address value
> + * CMDQ_CODE_JUMP:
> + * jump by offset
> + * format: op offset
> + * CMDQ_CODE_WFE:
> + * wait for event and clear
> + * it is just clear if no wait
> + * format: [wait] op event update:1 to_wait:1 wait:1
> + * [clear] op event update:1 to_wait:0 wait:0
> + * CMDQ_CODE_EOC:
> + * end of command
> + * format: op irq_flag
> + */
> +enum cmdq_code {
> + CMDQ_CODE_MOVE = 0x02,
> + CMDQ_CODE_WRITE = 0x04,
> + CMDQ_CODE_JUMP = 0x10,
> + CMDQ_CODE_WFE = 0x20,
> + CMDQ_CODE_EOC = 0x40,
> +};
> +
> +enum cmdq_task_state {
> + TASK_STATE_BUSY, /* running on a GCE thread */
> + TASK_STATE_ERROR,
> + TASK_STATE_DONE,
> +};
> +
> +struct cmdq_task_cb {
> + cmdq_async_flush_cb cb;
> + void *data;
> +};
> +
> +struct cmdq_thread {
> + void __iomem *base;
> + struct list_head task_busy_list;
> + wait_queue_head_t wait_task_done;
> +};
> +
> +struct cmdq_task {
> + struct cmdq *cmdq;
> + struct list_head list_entry;
> + enum cmdq_task_state task_state;
> + void *va_base;
> + dma_addr_t pa_base;
> + u64 engine_flag;
> + size_t command_size;
> + u32 num_cmd;
> + struct cmdq_thread *thread;
> + struct cmdq_task_cb cb;
> + struct work_struct release_work;
> +};
> +
> +struct cmdq {
> + struct device *dev;
> + void __iomem *base;
> + u32 irq;
> + struct workqueue_struct *task_release_wq;
> + struct cmdq_thread thread[CMDQ_THR_MAX_COUNT];
> + struct mutex task_mutex; /* for task */
> + spinlock_t exec_lock; /* for exec */
> + struct clk *clock;
> + bool suspended;
> +};
> +
> +struct cmdq_subsys {
> + u32 base;
> + int id;
> +};
> +
> +static const struct cmdq_subsys gce_subsys[] = {
> + {0x1400, 1},
> + {0x1401, 2},
> + {0x1402, 3},
> +};
> +
> +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_eng_get_thread(u64 flag)
> +{
> + if (flag & BIT_ULL(CMDQ_ENG_DISP_DSI0))
> + return CMDQ_THR_DISP_MAIN_IDX;
> + else if (flag & BIT_ULL(CMDQ_ENG_DISP_DPI0))
> + return CMDQ_THR_DISP_SUB_IDX;
> + else
> + return CMDQ_THR_DISP_MISC_IDX;
> +}
> +
> +static void cmdq_task_release(struct cmdq_task *task)
> +{
> + struct cmdq *cmdq = task->cmdq;
> +
> + dma_free_coherent(cmdq->dev, task->command_size, task->va_base,
> + task->pa_base);
> + kfree(task);
> +}
> +
> +static struct cmdq_task *cmdq_task_acquire(struct cmdq_rec *rec,
> + struct cmdq_task_cb cb)
> +{
> + struct cmdq *cmdq = rec->cmdq;
> + struct device *dev = cmdq->dev;
> + struct cmdq_task *task;
> +
> + task = kzalloc(sizeof(*task), GFP_KERNEL);
> + INIT_LIST_HEAD(&task->list_entry);
> + task->va_base = dma_alloc_coherent(dev, rec->command_size,
> + &task->pa_base, GFP_KERNEL);
> + if (!task->va_base) {
> + dev_err(dev, "allocate command buffer failed\n");
> + kfree(task);
> + return NULL;
> + }
> +
> + task->cmdq = cmdq;
> + task->command_size = rec->command_size;
> + task->engine_flag = rec->engine_flag;
> + task->task_state = TASK_STATE_BUSY;
> + task->cb = cb;
> + memcpy(task->va_base, rec->buf, rec->command_size);
> + task->num_cmd = task->command_size / CMDQ_INST_SIZE;
> + return task;
> +}
> +
> +static void cmdq_thread_writel(struct cmdq_thread *thread, u32 value,
> + u32 offset)
> +{
> + writel(value, thread->base + offset);
> +}
> +
> +static u32 cmdq_thread_readl(struct cmdq_thread *thread, u32 offset)
> +{
> + return readl(thread->base + offset);
> +}
> +
> +static int cmdq_thread_suspend(struct cmdq *cmdq, struct cmdq_thread *thread)
> +{
> + u32 status;
> +
> + cmdq_thread_writel(thread, CMDQ_THR_SUSPEND, CMDQ_THR_SUSPEND_TASK);
> +
> + /* If already disabled, treat as suspended successful. */
> + if (!(cmdq_thread_readl(thread, CMDQ_THR_ENABLE_TASK) &
> + CMDQ_THR_ENABLED))
> + return 0;
> +
> + if (readl_poll_timeout_atomic(thread->base + CMDQ_THR_CURR_STATUS,
> + status, status & CMDQ_THR_STATUS_SUSPENDED, 0, 10)) {
> + dev_err(cmdq->dev, "suspend GCE thread 0x%x failed\n",
> + (u32)(thread->base - cmdq->base));
> + return -EFAULT;
> + }
> +
> + return 0;
> +}
> +
> +static void cmdq_thread_resume(struct cmdq_thread *thread)
> +{
> + cmdq_thread_writel(thread, CMDQ_THR_RESUME, CMDQ_THR_SUSPEND_TASK);
> +}
> +
> +static int cmdq_thread_reset(struct cmdq *cmdq, struct cmdq_thread *thread)
> +{
> + u32 warm_reset;
> +
> + cmdq_thread_writel(thread, CMDQ_THR_DO_WARM_RESET, CMDQ_THR_WARM_RESET);
> + if (readl_poll_timeout_atomic(thread->base + CMDQ_THR_WARM_RESET,
> + warm_reset, !(warm_reset & CMDQ_THR_DO_WARM_RESET),
> + 0, 10)) {
> + dev_err(cmdq->dev, "reset GCE thread 0x%x failed\n",
> + (u32)(thread->base - cmdq->base));
> + return -EFAULT;
> + }
> + writel(CMDQ_THR_ACTIVE_SLOT_CYCLES, cmdq->base + CMDQ_THR_SLOT_CYCLES);
> + return 0;
> +}
> +
> +static void cmdq_thread_disable(struct cmdq *cmdq, struct cmdq_thread *thread)
> +{
> + cmdq_thread_reset(cmdq, thread);
> + cmdq_thread_writel(thread, CMDQ_THR_DISABLED, CMDQ_THR_ENABLE_TASK);
> +}
> +
> +/* notify GCE to re-fetch commands by setting GCE thread PC */
> +static void cmdq_thread_invalidate_fetched_data(struct cmdq_thread *thread)
> +{
> + cmdq_thread_writel(thread,
> + cmdq_thread_readl(thread, CMDQ_THR_CURR_ADDR),
> + CMDQ_THR_CURR_ADDR);
> +}
> +
> +static void cmdq_task_insert_into_thread(struct cmdq_task *task)
> +{
> + struct cmdq_thread *thread = task->thread;
> + struct cmdq_task *prev_task = list_last_entry(
> + &thread->task_busy_list, typeof(*task), list_entry);
> + u64 *prev_task_base = prev_task->va_base;
> +
> + /* let previous task jump to this task */
> + prev_task_base[prev_task->num_cmd - 1] = (u64)CMDQ_JUMP_BY_PA << 32 |
> + task->pa_base;
> +
> + cmdq_thread_invalidate_fetched_data(thread);
> +}
> +
> +/* we assume tasks in the same display GCE thread are waiting the same event. */
> +static void cmdq_task_remove_wfe(struct cmdq_task *task)
> +{
> + u32 wfe_option = CMDQ_WFE_UPDATE | CMDQ_WFE_WAIT | CMDQ_WFE_WAIT_VALUE;
> + u32 wfe_op = CMDQ_CODE_WFE << CMDQ_OP_CODE_SHIFT;
> + u32 *base = task->va_base;
> + u32 num_cmd = task->num_cmd << 1;
> + int i;
> +
> + for (i = 0; i < num_cmd; i += 2)
> + if (base[i] == wfe_option &&
> + (base[i + 1] & CMDQ_OP_CODE_MASK) == wfe_op) {
> + base[i] = CMDQ_JUMP_PASS;
> + base[i + 1] = CMDQ_JUMP_BY_OFFSET;
> + }
> +}
> +
> +static void cmdq_task_exec(struct cmdq_task *task, struct cmdq_thread *thread)
> +{
> + struct cmdq *cmdq = task->cmdq;
> + unsigned long flags;
> + unsigned long curr_pa, end_pa;
> +
> + WARN_ON(clk_prepare_enable(cmdq->clock) < 0);
> + spin_lock_irqsave(&cmdq->exec_lock, flags);
> + task->thread = thread;
> + task->task_state = TASK_STATE_BUSY;
> + if (list_empty(&thread->task_busy_list)) {
> + WARN_ON(cmdq_thread_reset(cmdq, thread) < 0);
> +
> + cmdq_thread_writel(thread, task->pa_base, CMDQ_THR_CURR_ADDR);
> + cmdq_thread_writel(thread, task->pa_base + task->command_size,
> + CMDQ_THR_END_ADDR);
> + cmdq_thread_writel(thread, CMDQ_THR_PRIORITY, CMDQ_THR_CFG);
> + cmdq_thread_writel(thread, CMDQ_THR_IRQ_EN,
> + CMDQ_THR_IRQ_ENABLE);
> +
> + cmdq_thread_writel(thread, CMDQ_THR_ENABLED,
> + CMDQ_THR_ENABLE_TASK);
> + } else {
> + WARN_ON(cmdq_thread_suspend(cmdq, thread) < 0);
> +
> + /*
> + * check boundary condition
> + * PC = END - 8, EOC is executed
> + * PC = END, all CMDs are executed
> + */
> + curr_pa = cmdq_thread_readl(thread, CMDQ_THR_CURR_ADDR);
> + end_pa = cmdq_thread_readl(thread, CMDQ_THR_END_ADDR);
> + if (curr_pa == end_pa - 8 || curr_pa == end_pa) {
> + /* set to this task directly */
> + cmdq_thread_writel(thread, task->pa_base,
> + CMDQ_THR_CURR_ADDR);
> + } else {
> + cmdq_task_insert_into_thread(task);
> +
> + if (thread == &cmdq->thread[CMDQ_THR_DISP_MAIN_IDX] ||
> + thread == &cmdq->thread[CMDQ_THR_DISP_SUB_IDX])
> + cmdq_task_remove_wfe(task);
> +
> + smp_mb(); /* modify jump before enable thread */
> + }
> +
> + cmdq_thread_writel(thread, task->pa_base + task->command_size,
> + CMDQ_THR_END_ADDR);
> + cmdq_thread_resume(thread);
> + }
> + list_move_tail(&task->list_entry, &thread->task_busy_list);
> + spin_unlock_irqrestore(&cmdq->exec_lock, flags);
> +}
> +
> +static void cmdq_handle_error_done(struct cmdq *cmdq,
> + struct cmdq_thread *thread, u32 irq_flag)
> +{
> + struct cmdq_task *task, *tmp, *curr_task = NULL;
> + u32 curr_pa;
> + struct cmdq_cb_data cmdq_cb_data;
> + bool err;
> +
> + if (irq_flag & CMDQ_THR_IRQ_ERROR)
> + err = true;
> + else if (irq_flag & CMDQ_THR_IRQ_DONE)
> + err = false;
> + else
> + return;
> +
> + curr_pa = cmdq_thread_readl(thread, CMDQ_THR_CURR_ADDR);
> +
> + list_for_each_entry_safe(task, tmp, &thread->task_busy_list,
> + list_entry) {
> + if (curr_pa >= task->pa_base &&
> + curr_pa < (task->pa_base + task->command_size))
> + curr_task = task;
> + if (task->cb.cb) {
> + cmdq_cb_data.err = curr_task ? err : false;
> + cmdq_cb_data.data = task->cb.data;
> + task->cb.cb(cmdq_cb_data);
> + }
> + task->task_state = (curr_task && err) ? TASK_STATE_ERROR :
> + TASK_STATE_DONE;
> + list_del(&task->list_entry);
> + if (curr_task)
> + break;
> + }
> +
> + wake_up(&thread->wait_task_done);
> +}
> +
> +static void cmdq_thread_irq_handler(struct cmdq *cmdq, int tid)
> +{
> + struct cmdq_thread *thread = &cmdq->thread[tid];
> + unsigned long flags = 0L;
> + u32 irq_flag;
> +
> + spin_lock_irqsave(&cmdq->exec_lock, flags);
> +
> + irq_flag = cmdq_thread_readl(thread, CMDQ_THR_IRQ_STATUS);
> + cmdq_thread_writel(thread, ~irq_flag, CMDQ_THR_IRQ_STATUS);
> +
> + /*
> + * Another CPU core could run "release task" right before we acquire
> + * the spin lock, and thus reset / disable this GCE thread, so we
> + * need to check the enable bit of this GCE thread.
> + */
> + if (!(cmdq_thread_readl(thread, CMDQ_THR_ENABLE_TASK) &
> + CMDQ_THR_ENABLED))
> + irq_flag = 0;

These three statement (clear irq flag and detect thread enable) can be
moved into cmdq_handle_error_done() and the duplicated part in
cmdq_task_handle_error_result() can be removed. Even though
cmdq_task_handle_error_result() need not check thread enable, it would
not influence the flow.

> +
> + cmdq_handle_error_done(cmdq, thread, irq_flag);
> + spin_unlock_irqrestore(&cmdq->exec_lock, flags);
> +}
> +
> +static irqreturn_t cmdq_irq_handler(int irq, void *dev)
> +{
> + struct cmdq *cmdq = dev;
> + u32 irq_status;
> + int i;
> +
> + irq_status = readl(cmdq->base + CMDQ_CURR_IRQ_STATUS);
> + irq_status &= CMDQ_IRQ_MASK;
> + irq_status ^= CMDQ_IRQ_MASK;
> +
> + if (!irq_status)
> + return IRQ_NONE;
> +
> + while (irq_status) {
> + i = ffs(irq_status) - 1;
> + irq_status &= ~BIT(i);
> + cmdq_thread_irq_handler(cmdq, i);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static int cmdq_task_handle_error_result(struct cmdq_task *task)
> +{
> + struct cmdq *cmdq = task->cmdq;
> + struct device *dev = cmdq->dev;
> + struct cmdq_thread *thread = task->thread;
> + struct cmdq_task *next_task, *prev_task;
> + u32 irq_flag;
> +
> + /* suspend GCE thread to ensure consistency */
> + WARN_ON(cmdq_thread_suspend(cmdq, thread) < 0);
> +
> + /* ISR has handled this error task */
> + if (task->task_state == TASK_STATE_ERROR) {
> + next_task = list_first_entry_or_null(&thread->task_busy_list,
> + struct cmdq_task, list_entry);
> + if (next_task) /* move to next task */
> + cmdq_thread_writel(thread, next_task->pa_base,
> + CMDQ_THR_CURR_ADDR);
> + cmdq_thread_resume(thread);
> + return -ECANCELED;
> + }
> +
> + /*
> + * Save next_task and prev_task in advance
> + * since cmdq_handle_error_done will remove list_entry.
> + */
> + next_task = prev_task = NULL;
> + if (task->list_entry.next != &thread->task_busy_list)
> + next_task = list_next_entry(task, list_entry);
> + if (task->list_entry.prev != &thread->task_busy_list)
> + prev_task = list_prev_entry(task, list_entry);

I think there is always no previous task because task order in
thread->task_busy_list is the same as in cmdq->task_release_wq. So each
task processed by release work should be the first item in
thread->task_busy_list or be removed from thread->task_busy_list.

> +
> + /*
> + * Although IRQ is disabled, GCE continues to execute.
> + * It may have pending IRQ before GCE thread is suspended,
> + * so check this condition again.
> + */
> + irq_flag = cmdq_thread_readl(thread, CMDQ_THR_IRQ_STATUS);
> + cmdq_handle_error_done(cmdq, thread, irq_flag);
> + cmdq_thread_writel(thread, ~irq_flag, CMDQ_THR_IRQ_STATUS);
> +
> + if (task->task_state == TASK_STATE_DONE) {
> + cmdq_thread_resume(thread);
> + return 0;
> + }
> +
> + if (task->task_state == TASK_STATE_ERROR) {
> + dev_err(dev, "task 0x%p error\n", task);
> + if (next_task) /* move to next task */
> + cmdq_thread_writel(thread, next_task->pa_base,
> + CMDQ_THR_CURR_ADDR);
> + cmdq_thread_resume(thread);
> + return -ECANCELED;
> + }
> +
> + /* Task is running, so we force to remove it. */
> + dev_err(dev, "task 0x%p timeout or killed\n", task);

No 'kill' state.

> + task->task_state = TASK_STATE_ERROR;
> +
> + if (prev_task) {
> + u64 *prev_va = prev_task->va_base;
> + u64 *curr_va = task->va_base;
> +
> + /* copy JUMP instruction */
> + prev_va[prev_task->num_cmd - 1] = curr_va[task->num_cmd - 1];
> +
> + cmdq_thread_invalidate_fetched_data(thread);
> + } else if (next_task) { /* move to next task */
> + cmdq_thread_writel(thread, next_task->pa_base,
> + CMDQ_THR_CURR_ADDR);
> + }

Just one statement in 'else if' part. So remove the parentheses.

> +
> + list_del(&task->list_entry);
> + cmdq_thread_resume(thread);
> +
> + /* call cb here to prevent lock */

I think these three statements should be place together and there should
be no this comment.

1. Change task state to DONE or ERROR.
2. Callback
3. Remove task from task_busy_list.

> + if (task->cb.cb) {
> + struct cmdq_cb_data cmdq_cb_data;
> +
> + cmdq_cb_data.err = true;
> + cmdq_cb_data.data = task->cb.data;
> + task->cb.cb(cmdq_cb_data);
> + }
> +
> + return -ECANCELED;
> +}
> +
> +static void cmdq_task_wait_release_work(struct work_struct *work_item)
> +{
> + struct cmdq_task *task = container_of(work_item, struct cmdq_task,
> + release_work);
> + struct cmdq *cmdq = task->cmdq;
> + struct cmdq_thread *thread = task->thread;
> + unsigned long flags;
> +
> + wait_event_timeout(thread->wait_task_done,
> + task->task_state != TASK_STATE_BUSY,
> + msecs_to_jiffies(CMDQ_TIMEOUT_MS));
> +
> + spin_lock_irqsave(&cmdq->exec_lock, flags);
> + if (task->task_state != TASK_STATE_DONE)
> + cmdq_task_handle_error_result(task);
> + if (list_empty(&thread->task_busy_list))
> + cmdq_thread_disable(cmdq, thread);
> + spin_unlock_irqrestore(&cmdq->exec_lock, flags);
> +
> + /* release regardless of success or not */
> + clk_disable_unprepare(cmdq->clock);
> + cmdq_task_release(task);
> +}
> +
> +static void cmdq_task_wait_release_schedule(struct cmdq_task *task)
> +{
> + struct cmdq *cmdq = task->cmdq;
> +
> + INIT_WORK(&task->release_work, cmdq_task_wait_release_work);
> + queue_work(cmdq->task_release_wq, &task->release_work);
> +}
> +
> +static int cmdq_rec_realloc_cmd_buffer(struct cmdq_rec *rec, size_t size)
> +{
> + void *new_buf;
> +
> + new_buf = krealloc(rec->buf, size, GFP_KERNEL | __GFP_ZERO);
> + if (!new_buf)
> + return -ENOMEM;
> + rec->buf = new_buf;
> + rec->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);
> +
> +int cmdq_rec_create(struct device *dev, u64 engine_flag,
> + struct cmdq_rec **rec_ptr)
> +{
> + struct cmdq_rec *rec;
> + int err;
> +
> + rec = kzalloc(sizeof(*rec), GFP_KERNEL);
> + if (!rec)
> + return -ENOMEM;
> + rec->cmdq = dev_get_drvdata(dev);
> + rec->engine_flag = engine_flag;
> + err = cmdq_rec_realloc_cmd_buffer(rec, CMDQ_INITIAL_CMD_BLOCK_SIZE);
> + if (err < 0) {
> + kfree(rec);
> + return err;
> + }
> + *rec_ptr = rec;
> + return 0;
> +}
> +EXPORT_SYMBOL(cmdq_rec_create);
> +
> +static int cmdq_rec_append_command(struct cmdq_rec *rec, enum cmdq_code code,
> + u32 arg_a, u32 arg_b)
> +{
> + u64 *cmd_ptr;
> + int err;
> +
> + if (WARN_ON(rec->finalized))
> + return -EBUSY;
> + if (code < CMDQ_CODE_MOVE || code > CMDQ_CODE_EOC)
> + return -EINVAL;
> + if (unlikely(rec->command_size + CMDQ_INST_SIZE > rec->buf_size)) {
> + err = cmdq_rec_realloc_cmd_buffer(rec, rec->buf_size * 2);
> + if (err < 0)
> + return err;
> + }
> + cmd_ptr = rec->buf + rec->command_size;
> + (*cmd_ptr) = (u64)((code << CMDQ_OP_CODE_SHIFT) | arg_a) << 32 | arg_b;
> + rec->command_size += CMDQ_INST_SIZE;
> + return 0;
> +}
> +
> +int cmdq_rec_write(struct cmdq_rec *rec, u32 value, struct cmdq_base *base,
> + u32 offset)
> +{
> + u32 arg_a = ((base->base + offset) & CMDQ_ARG_A_WRITE_MASK) |
> + ((base->subsys & CMDQ_SUBSYS_MASK) << CMDQ_SUBSYS_SHIFT);
> + return cmdq_rec_append_command(rec, CMDQ_CODE_WRITE, arg_a, value);
> +}
> +EXPORT_SYMBOL(cmdq_rec_write);
> +
> +int cmdq_rec_write_mask(struct cmdq_rec *rec, u32 value,
> + struct cmdq_base *base, u32 offset, u32 mask)
> +{
> + u32 offset_mask = offset;
> + int err;
> +
> + if (mask != 0xffffffff) {
> + err = cmdq_rec_append_command(rec, CMDQ_CODE_MOVE, 0, ~mask);
> + if (err < 0)
> + return err;
> + offset_mask |= CMDQ_WRITE_ENABLE_MASK;
> + }
> + return cmdq_rec_write(rec, value, base, offset_mask);
> +}
> +EXPORT_SYMBOL(cmdq_rec_write_mask);
> +
> +int cmdq_rec_wfe(struct cmdq_rec *rec, enum cmdq_event event)
> +{
> + u32 arg_b;
> +
> + if (event >= CMDQ_MAX_HW_EVENT_COUNT || event < 0)
> + return -EINVAL;
> +
> + /*
> + * 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_rec_append_command(rec, CMDQ_CODE_WFE, event, arg_b);
> +}
> +EXPORT_SYMBOL(cmdq_rec_wfe);
> +
> +int cmdq_rec_clear_event(struct cmdq_rec *rec, enum cmdq_event event)
> +{
> + if (event >= CMDQ_MAX_HW_EVENT_COUNT || event < 0)
> + return -EINVAL;
> +
> + return cmdq_rec_append_command(rec, CMDQ_CODE_WFE, event,
> + CMDQ_WFE_UPDATE);
> +}
> +EXPORT_SYMBOL(cmdq_rec_clear_event);
> +
> +static int cmdq_rec_finalize(struct cmdq_rec *rec)
> +{
> + int err;
> +
> + if (rec->finalized)
> + return 0;
> +
> + /* insert EOC and generate IRQ for each command iteration */
> + err = cmdq_rec_append_command(rec, CMDQ_CODE_EOC, 0, CMDQ_EOC_IRQ_EN);
> + if (err < 0)
> + return err;
> +
> + /* JUMP to end */
> + err = cmdq_rec_append_command(rec, CMDQ_CODE_JUMP, 0, CMDQ_JUMP_PASS);
> + if (err < 0)
> + return err;
> +
> + rec->finalized = true;
> + return 0;
> +}
> +
> +int cmdq_rec_flush_async(struct cmdq_rec *rec, cmdq_async_flush_cb cb,
> + void *data)
> +{
> + struct cmdq *cmdq = rec->cmdq;
> + struct cmdq_task *task;
> + struct cmdq_task_cb task_cb;
> + struct cmdq_thread *thread;
> + int err;
> +
> + mutex_lock(&cmdq->task_mutex);
> + if (cmdq->suspended) {
> + dev_err(cmdq->dev, "%s is called after suspended\n", __func__);
> + mutex_unlock(&cmdq->task_mutex);
> + return -EPERM;
> + }
> +
> + err = cmdq_rec_finalize(rec);
> + if (err < 0) {
> + mutex_unlock(&cmdq->task_mutex);
> + return err;
> + }
> +
> + task_cb.cb = cb;
> + task_cb.data = data;
> + task = cmdq_task_acquire(rec, task_cb);
> + if (!task) {
> + mutex_unlock(&cmdq->task_mutex);
> + return -EFAULT;
> + }
> +
> + thread = &cmdq->thread[cmdq_eng_get_thread(task->engine_flag)];
> + cmdq_task_exec(task, thread);
> + cmdq_task_wait_release_schedule(task);
> + mutex_unlock(&cmdq->task_mutex);
> + return 0;
> +}
> +EXPORT_SYMBOL(cmdq_rec_flush_async);
> +
> +struct cmdq_flush_completion {
> + struct completion cmplt;
> + bool err;
> +};
> +
> +static int cmdq_rec_flush_cb(struct cmdq_cb_data data)
> +{
> + struct cmdq_flush_completion *cmplt = data.data;
> +
> + cmplt->err = data.err;
> + complete(&cmplt->cmplt);
> + return 0;
> +}
> +
> +int cmdq_rec_flush(struct cmdq_rec *rec)
> +{
> + struct cmdq_flush_completion cmplt;
> + int err;
> +
> + init_completion(&cmplt.cmplt);
> + err = cmdq_rec_flush_async(rec, cmdq_rec_flush_cb, &cmplt);
> + if (err < 0)
> + return err;
> + wait_for_completion(&cmplt.cmplt);
> + return cmplt.err ? -EFAULT : 0;
> +}
> +EXPORT_SYMBOL(cmdq_rec_flush);
> +
> +void cmdq_rec_destroy(struct cmdq_rec *rec)
> +{
> + kfree(rec->buf);
> + kfree(rec);
> +}
> +EXPORT_SYMBOL(cmdq_rec_destroy);
> +
> +static bool cmdq_task_is_empty(struct cmdq *cmdq)
> +{
> + struct cmdq_thread *thread;
> + int i;
> +
> + for (i = 0; i < ARRAY_SIZE(cmdq->thread); i++) {
> + thread = &cmdq->thread[i];
> + if (!list_empty(&thread->task_busy_list))
> + return false;
> + }
> + return true;
> +}
> +
> +static int cmdq_suspend(struct device *dev)
> +{
> + struct cmdq *cmdq = dev_get_drvdata(dev);
> + u32 exec_threads;
> +
> + mutex_lock(&cmdq->task_mutex);
> + cmdq->suspended = true;
> + mutex_unlock(&cmdq->task_mutex);
> +
> + exec_threads = readl(cmdq->base + CMDQ_CURR_LOADED_THR);
> + if ((exec_threads & CMDQ_THR_EXECUTING) && !cmdq_task_is_empty(cmdq)) {
> + dev_err(dev, "wait active tasks timeout.\n");
> + flush_workqueue(cmdq->task_release_wq);
> + }

Maybe it need not to check exec_threads, it may be written as:

if (!cmdq_task_is_empty(cmdq))
dev_err(dev, "wait active tasks timeout.\n");

flush_workqueue(cmdq->task_release_wq);

Even though task_busy_list is empty, that does not mean every task in
cmdq->task_release_wq is finished. So always do flush
cmdq->task_release_wq.

> + return 0;
> +}
> +
> +static int cmdq_resume(struct device *dev)
> +{
> + struct cmdq *cmdq = dev_get_drvdata(dev);
> +
> + cmdq->suspended = false;
> + return 0;
> +}
> +
> +static int cmdq_remove(struct platform_device *pdev)
> +{
> + struct cmdq *cmdq = platform_get_drvdata(pdev);
> +
> + destroy_workqueue(cmdq->task_release_wq);
> + cmdq->task_release_wq = NULL;
> + return 0;
> +}
> +
> +static int cmdq_probe(struct platform_device *pdev)
> +{
> + struct device *dev = &pdev->dev;
> + struct device_node *node = dev->of_node;
> + struct resource *res;
> + struct cmdq *cmdq;
> + int err, i;
> +
> + cmdq = devm_kzalloc(dev, sizeof(*cmdq), GFP_KERNEL);
> + if (!cmdq)
> + return -ENOMEM;
> + cmdq->dev = dev;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + cmdq->base = devm_ioremap_resource(dev, res);
> + if (IS_ERR(cmdq->base)) {
> + dev_err(dev, "failed to ioremap gce\n");
> + return PTR_ERR(cmdq->base);
> + }
> +
> + cmdq->irq = irq_of_parse_and_map(node, 0);
> + if (!cmdq->irq) {
> + dev_err(dev, "failed to get irq\n");
> + return -EINVAL;
> + }
> +
> + dev_dbg(dev, "cmdq device: addr:0x%p, va:0x%p, irq:%d\n",
> + dev, cmdq->base, cmdq->irq);
> +
> + mutex_init(&cmdq->task_mutex);
> + spin_lock_init(&cmdq->exec_lock);
> + cmdq->task_release_wq = alloc_ordered_workqueue(
> + "%s", WQ_MEM_RECLAIM | WQ_HIGHPRI,
> + "cmdq_task_wait_release");
> +
> + for (i = 0; i < ARRAY_SIZE(cmdq->thread); i++) {
> + cmdq->thread[i].base = cmdq->base + CMDQ_THR_BASE +
> + CMDQ_THR_SHIFT * i;
> + init_waitqueue_head(&cmdq->thread[i].wait_task_done);
> + INIT_LIST_HEAD(&cmdq->thread[i].task_busy_list);
> + }
> +
> + platform_set_drvdata(pdev, cmdq);
> +
> + err = devm_request_irq(dev, cmdq->irq, cmdq_irq_handler, IRQF_SHARED,
> + CMDQ_DRIVER_DEVICE_NAME, cmdq);
> + if (err < 0) {
> + dev_err(dev, "failed to register ISR (%d)\n", err);
> + goto fail;
> + }
> +
> + cmdq->clock = devm_clk_get(dev, CMDQ_CLK_NAME);
> + if (IS_ERR(cmdq->clock)) {
> + dev_err(dev, "failed to get clk:%s\n", CMDQ_CLK_NAME);
> + err = PTR_ERR(cmdq->clock);
> + goto fail;
> + }
> + return 0;
> +
> +fail:
> + cmdq_remove(pdev);
> + return err;
> +}
> +
> +static const struct dev_pm_ops cmdq_pm_ops = {
> + .suspend = cmdq_suspend,
> + .resume = cmdq_resume,
> +};
> +
> +static const struct of_device_id cmdq_of_ids[] = {
> + {.compatible = "mediatek,mt8173-gce",},
> + {}
> +};
> +
> +static struct platform_driver cmdq_drv = {
> + .probe = cmdq_probe,
> + .remove = cmdq_remove,
> + .driver = {
> + .name = CMDQ_DRIVER_DEVICE_NAME,
> + .owner = THIS_MODULE,
> + .pm = &cmdq_pm_ops,
> + .of_match_table = cmdq_of_ids,
> + }
> +};
> +
> +builtin_platform_driver(cmdq_drv);
> diff --git a/include/soc/mediatek/cmdq.h b/include/soc/mediatek/cmdq.h
> new file mode 100644
> index 0000000..60eef3d
> --- /dev/null
> +++ b/include/soc/mediatek/cmdq.h
> @@ -0,0 +1,197 @@
> +/*
> + * 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/platform_device.h>
> +#include <linux/types.h>
> +
> +enum cmdq_eng {
> + CMDQ_ENG_DISP_AAL,
> + CMDQ_ENG_DISP_COLOR0,
> + CMDQ_ENG_DISP_COLOR1,
> + CMDQ_ENG_DISP_DPI0,
> + CMDQ_ENG_DISP_DSI0,
> + CMDQ_ENG_DISP_DSI1,
> + CMDQ_ENG_DISP_GAMMA,
> + CMDQ_ENG_DISP_OD,
> + CMDQ_ENG_DISP_OVL0,
> + CMDQ_ENG_DISP_OVL1,
> + CMDQ_ENG_DISP_PWM0,
> + CMDQ_ENG_DISP_PWM1,
> + CMDQ_ENG_DISP_RDMA0,
> + CMDQ_ENG_DISP_RDMA1,
> + CMDQ_ENG_DISP_RDMA2,
> + CMDQ_ENG_DISP_UFOE,
> + CMDQ_ENG_DISP_WDMA0,
> + CMDQ_ENG_DISP_WDMA1,
> + CMDQ_ENG_MAX,
> +};
> +
> +/* events for CMDQ and display */
> +enum cmdq_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,
> + /* Keep this at the end of HW events */
> + CMDQ_MAX_HW_EVENT_COUNT = 260,
> +};
> +
> +struct cmdq_cb_data {
> + bool err;
> + void *data;
> +};
> +
> +typedef int (*cmdq_async_flush_cb)(struct cmdq_cb_data data);
> +
> +struct cmdq_task;
> +struct cmdq;
> +
> +struct cmdq_rec {
> + struct cmdq *cmdq;
> + u64 engine_flag;
> + size_t command_size;
> + void *buf;
> + size_t buf_size;
> + bool finalized;
> +};
> +
> +struct cmdq_base {
> + int subsys;
> + u32 base;
> +};
> +
> +/**
> + * cmdq_register_device() - register device which needs CMDQ
> + * @dev: device
> + *
> + * Return: cmdq_base pointer or NULL for failed
> + */
> +struct cmdq_base *cmdq_register_device(struct device *dev);
> +
> +/**
> + * cmdq_rec_create() - create command queue record
> + * @dev: device
> + * @engine_flag: command queue engine flag
> + * @rec_ptr: command queue record pointer to retrieve cmdq_rec
> + *
> + * Return: 0 for success; else the error code is returned
> + */
> +int cmdq_rec_create(struct device *dev, u64 engine_flag,
> + struct cmdq_rec **rec_ptr);
> +
> +/**
> + * cmdq_rec_write() - append write command to the command queue record
> + * @rec: the command queue record
> + * @value: the specified target register value
> + * @base: the command queue base
> + * @offset: register offset from module base
> + *
> + * Return: 0 for success; else the error code is returned
> + */
> +int cmdq_rec_write(struct cmdq_rec *rec, u32 value,
> + struct cmdq_base *base, u32 offset);
> +
> +/**
> + * cmdq_rec_write_mask() - append write command with mask to the command
> + * queue record
> + * @rec: the command queue record
> + * @value: the specified target register value
> + * @base: the command queue 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_rec_write_mask(struct cmdq_rec *rec, u32 value,
> + struct cmdq_base *base, u32 offset, u32 mask);
> +
> +/**
> + * cmdq_rec_wfe() - append wait for event command to the command queue record
> + * @rec: the command queue record
> + * @event: the desired event type to "wait and CLEAR"
> + *
> + * Return: 0 for success; else the error code is returned
> + */
> +int cmdq_rec_wfe(struct cmdq_rec *rec, enum cmdq_event event);
> +
> +/**
> + * cmdq_rec_clear_event() - append clear event command to the command queue
> + * record
> + * @rec: the command queue record
> + * @event: the desired event to be cleared
> + *
> + * Return: 0 for success; else the error code is returned
> + */
> +int cmdq_rec_clear_event(struct cmdq_rec *rec, enum cmdq_event event);
> +
> +/**
> + * cmdq_rec_flush() - trigger CMDQ to execute the recorded commands
> + * @rec: the command queue record
> + *
> + * Return: 0 for success; else the error code is returned
> + *
> + * Trigger CMDQ to execute the recorded commands. Note that this is a
> + * synchronous flush function. When the function returned, the recorded
> + * commands have been done.
> + */
> +int cmdq_rec_flush(struct cmdq_rec *rec);
> +
> +/**
> + * cmdq_rec_flush_async() - trigger CMDQ to asynchronously execute the recorded
> + * commands and call back after ISR is finished
> + * @rec: the command queue record
> + * @cb: called in the end of CMDQ ISR
> + * @data: this data will pass back to cb
> + *
> + * Return: 0 for success; else the error code is returned
> + *
> + * Trigger CMDQ to asynchronously execute the recorded commands and call back
> + * after ISR is finished. Note that this is an ASYNC function. When the function
> + * returned, it may or may not be finished. The ISR callback function is called
> + * in the end of ISR.
> + */
> +int cmdq_rec_flush_async(struct cmdq_rec *rec, cmdq_async_flush_cb cb,
> + void *data);
> +
> +/**
> + * cmdq_rec_destroy() - destroy command queue record
> + * @rec: the command queue record
> + */
> +void cmdq_rec_destroy(struct cmdq_rec *rec);
> +
> +#endif /* __MTK_CMDQ_H__ */

Regards,
CK