add helper functions to create and send commands to

the global command engine (GCE) device using the
 command queue driver (cmdq).
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Merge tag 'v4.20-next-soc' of https://git.kernel.org/pub/scm/linux/kernel/git/matthias.bgg/linux into next/drivers

add helper functions to create and send commands to
the global command engine (GCE) device using the
command queue driver (cmdq).

* tag 'v4.20-next-soc' of https://git.kernel.org/pub/scm/linux/kernel/git/matthias.bgg/linux:
  soc: mediatek: Add Mediatek CMDQ helper

Signed-off-by: Olof Johansson <olof@lixom.net>

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

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

drivers/soc/mediatek/mtk-cmdq-helper.c

@@ -0,0 +1,300 @@
+// 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/module.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;
+
+		dev_err(dev, "failed to request channel\n");
+		err = PTR_ERR(client->chan);
+		kfree(client);
+
+		return ERR_PTR(err);
+	}
+
+	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);
+
+struct cmdq_pkt *cmdq_pkt_create(struct cmdq_client *client, size_t size)
+{
+	struct cmdq_pkt *pkt;
+	struct device *dev;
+	dma_addr_t dma_addr;
+
+	pkt = kzalloc(sizeof(*pkt), GFP_KERNEL);
+	if (!pkt)
+		return ERR_PTR(-ENOMEM);
+	pkt->va_base = kzalloc(size, GFP_KERNEL);
+	if (!pkt->va_base) {
+		kfree(pkt);
+		return ERR_PTR(-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 ERR_PTR(-ENOMEM);
+	}
+
+	pkt->pa_base = dma_addr;
+
+	return pkt;
+}
+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)) {
+		/*
+		 * In the case of allocated buffer size (pkt->buf_size) is used
+		 * up, the real required size (pkt->cmdq_buf_size) is still
+		 * increased, so that the user knows how much memory should be
+		 * ultimately allocated after appending all commands and
+		 * flushing the command packet. Therefor, the user can call
+		 * cmdq_pkt_create() again with the real required buffer size.
+		 */
+		pkt->cmd_buf_size += CMDQ_INST_SIZE;
+		WARN_ONCE(1, "%s: buffer size %u is too small !\n",
+			__func__, (u32)pkt->buf_size);
+		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 = 0;
+
+	if (mask != 0xffffffff) {
+		err = cmdq_pkt_append_command(pkt, CMDQ_CODE_MASK, 0, ~mask);
+		offset_mask |= CMDQ_WRITE_ENABLE_MASK;
+	}
+	err |= cmdq_pkt_write(pkt, value, subsys, offset_mask);
+
+	return err;
+}
+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);
+
+	/* JUMP to end */
+	err |= cmdq_pkt_append_command(pkt, CMDQ_CODE_JUMP, 0, CMDQ_JUMP_PASS);
+
+	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);
+
+MODULE_LICENSE("GPL v2");

include/linux/soc/mediatek/mtk-cmdq.h

@@ -0,0 +1,133 @@
+/* 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
+ * @size:	required CMDQ buffer size
+ *
+ * Return: CMDQ packet pointer
+ */
+struct cmdq_pkt *cmdq_pkt_create(struct cmdq_client *client, 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_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);
+
+/**
+ * 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);
+
+#endif	/* __MTK_CMDQ_H__ */