drm/rockchip: add an common abstracted PSR driver

The PSR driver have exported four symbols for specific device driver, and
it's safe to call them in interrupt context:
- rockchip_drm_psr_register()
- rockchip_drm_psr_unregister()
- rockchip_drm_psr_enable()
- rockchip_drm_psr_disable()
- rockchip_drm_psr_flush()

Encoder driver should call the register/unregister interfaces to hook
itself into common PSR driver, encoder have implement the 'psr_set'
callback which use the set PSR state in hardware side.

Crtc driver would call the enable/disable interfaces when vblank is
enable/disable, after that the common PSR driver would call the encoder
registered callback to set the PSR state.

Fb driver would call the flush interface in 'fb->dirty' callback, this
helper function would force all PSR enabled encoders to exit from PSR
for 3 seconds.

Signed-off-by: Yakir Yang <ykk@rock-chips.com>
[seanpaul removed leftover psr_enabled/psr_work kruft from drm_vop.c]
Signed-off-by: Sean Paul <seanpaul@chromium.org>

1 files changed, 249 insertions, 0 deletions

diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_psr.c b/drivers/gpu/drm/rockchip/rockchip_drm_psr.c
new file mode 100644
index 000000000000..a6d3bd25b905
--- /dev/null
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_psr.c
@@ -0,0 +1,249 @@
+/*
+ * Copyright (C) Fuzhou Rockchip Electronics Co.Ltd
+ * Author: Yakir Yang <ykk@rock-chips.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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 <drm/drmP.h>
+#include <drm/drm_crtc_helper.h>
+
+#include "rockchip_drm_drv.h"
+#include "rockchip_drm_psr.h"
+
+#define PSR_FLUSH_TIMEOUT	msecs_to_jiffies(3000) /* 3 seconds */
+#define PSR_SET_DELAY_TIME	msecs_to_jiffies(10)
+
+enum psr_state {
+	PSR_FLUSH,
+	PSR_ENABLE,
+	PSR_DISABLE,
+};
+
+struct psr_drv {
+	struct list_head	list;
+	struct drm_encoder	*encoder;
+
+	enum psr_state		request_state;
+	enum psr_state		state;
+
+	struct delayed_work	state_work;
+
+	struct timer_list	flush_timer;
+
+	void (*set)(struct drm_encoder *encoder, bool enable);
+};
+
+static struct psr_drv *find_psr_by_crtc(struct drm_crtc *crtc)
+{
+	struct rockchip_drm_private *drm_drv = crtc->dev->dev_private;
+	struct psr_drv *psr;
+
+	list_for_each_entry(psr, &drm_drv->psr_list, list)
+		if (psr->encoder->crtc == crtc)
+			return psr;
+
+	return ERR_PTR(-ENODEV);
+}
+
+static void psr_state_work(struct work_struct *work)
+{
+	struct psr_drv *psr = container_of(work, typeof(*psr), state_work.work);
+	enum psr_state request_state = psr->request_state;
+
+	/*
+	 * Allowed finite state machine:
+	 *
+	 *   PSR_ENABLE  < = = = = = >  PSR_FLUSH
+	  *      | ^                        |
+	  *      | |                        |
+	  *      v |                        |
+	 *   PSR_DISABLE < - - - - - - - - -
+	 */
+
+	/* Forbid no state change */
+	if (request_state == psr->state)
+		return;
+
+	/* Forbid DISABLE change to FLUSH */
+	if (request_state == PSR_FLUSH && psr->state == PSR_DISABLE)
+		return;
+
+	/* Allow but no need hardware change, just need assign the state */
+	if (request_state == PSR_DISABLE && psr->state == PSR_FLUSH) {
+		psr->state = request_state;
+		return;
+	}
+
+	/* Only wrote in this work, no need lock protection */
+	psr->state = request_state;
+
+	/* Refact to hardware state change */
+	switch (request_state) {
+	case PSR_ENABLE:
+		psr->set(psr->encoder, true);
+		break;
+
+	case PSR_DISABLE:
+	case PSR_FLUSH:
+		psr->set(psr->encoder, false);
+		break;
+	}
+}
+
+static void psr_set_state(struct psr_drv *psr, enum psr_state state)
+{
+	psr->request_state = state;
+
+	schedule_delayed_work(&psr->state_work, PSR_SET_DELAY_TIME);
+}
+
+static void psr_flush_handler(unsigned long data)
+{
+	struct psr_drv *psr = (struct psr_drv *)data;
+
+	if (!psr)
+		return;
+
+	/* State changed between flush time, then keep it */
+	if (psr->request_state != PSR_FLUSH)
+		return;
+
+	psr_set_state(psr, PSR_ENABLE);
+}
+
+/**
+ * rockchip_drm_psr_enable - enable the encoder PSR which bind to given CRTC
+ * @crtc: CRTC to obtain the PSR encoder
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int rockchip_drm_psr_enable(struct drm_crtc *crtc)
+{
+	struct psr_drv *psr = find_psr_by_crtc(crtc);
+
+	if (IS_ERR(psr))
+		return PTR_ERR(psr);
+
+	psr_set_state(psr, PSR_ENABLE);
+	return 0;
+}
+EXPORT_SYMBOL(rockchip_drm_psr_enable);
+
+/**
+ * rockchip_drm_psr_disable - disable the encoder PSR which bind to given CRTC
+ * @crtc: CRTC to obtain the PSR encoder
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int rockchip_drm_psr_disable(struct drm_crtc *crtc)
+{
+	struct psr_drv *psr = find_psr_by_crtc(crtc);
+
+	if (IS_ERR(psr))
+		return PTR_ERR(psr);
+
+	psr_set_state(psr, PSR_DISABLE);
+	return 0;
+}
+EXPORT_SYMBOL(rockchip_drm_psr_disable);
+
+/**
+ * rockchip_drm_psr_flush - force to flush all registered PSR encoders
+ * @dev: drm device
+ *
+ * Disable the PSR function for all registered encoders, and then enable the
+ * PSR function back after PSR_FLUSH_TIMEOUT. If encoder PSR state have been
+ * changed during flush time, then keep the state no change after flush
+ * timeout.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+void rockchip_drm_psr_flush(struct drm_device *dev)
+{
+	struct rockchip_drm_private *drm_drv = dev->dev_private;
+	struct psr_drv *psr;
+
+	list_for_each_entry(psr, &drm_drv->psr_list, list) {
+		if (psr->request_state == PSR_DISABLE)
+			continue;
+
+		mod_timer(&psr->flush_timer,
+			  round_jiffies_up(jiffies + PSR_FLUSH_TIMEOUT));
+
+		psr_set_state(psr, PSR_FLUSH);
+	}
+}
+EXPORT_SYMBOL(rockchip_drm_psr_flush);
+
+/**
+ * rockchip_drm_psr_register - register encoder to psr driver
+ * @encoder: encoder that obtain the PSR function
+ * @psr_set: call back to set PSR state
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int rockchip_drm_psr_register(struct drm_encoder *encoder,
+			void (*psr_set)(struct drm_encoder *, bool enable))
+{
+	struct rockchip_drm_private *drm_drv = encoder->dev->dev_private;
+	struct psr_drv *psr;
+
+	if (!encoder || !psr_set)
+		return -EINVAL;
+
+	psr = kzalloc(sizeof(struct psr_drv), GFP_KERNEL);
+	if (!psr)
+		return -ENOMEM;
+
+	setup_timer(&psr->flush_timer, psr_flush_handler, (unsigned long)psr);
+
+	INIT_DELAYED_WORK(&psr->state_work, psr_state_work);
+
+	psr->state = PSR_DISABLE;
+	psr->encoder = encoder;
+	psr->set = psr_set;
+
+	mutex_lock(&drm_drv->psr_list_mutex);
+	list_add_tail(&psr->list, &drm_drv->psr_list);
+	mutex_unlock(&drm_drv->psr_list_mutex);
+
+	return 0;
+}
+EXPORT_SYMBOL(rockchip_drm_psr_register);
+
+/**
+ * rockchip_drm_psr_unregister - unregister encoder to psr driver
+ * @encoder: encoder that obtain the PSR function
+ * @psr_set: call back to set PSR state
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+void rockchip_drm_psr_unregister(struct drm_encoder *encoder)
+{
+	struct rockchip_drm_private *drm_drv = encoder->dev->dev_private;
+	struct psr_drv *psr, *n;
+
+	mutex_lock(&drm_drv->psr_list_mutex);
+	list_for_each_entry_safe(psr, n, &drm_drv->psr_list, list) {
+		if (psr->encoder == encoder) {
+			del_timer(&psr->flush_timer);
+			list_del(&psr->list);
+			kfree(psr);
+		}
+	}
+	mutex_unlock(&drm_drv->psr_list_mutex);
+}
+EXPORT_SYMBOL(rockchip_drm_psr_unregister);