Re: [PATCH v6 12/19] drm/imx: Add i.MX8qxp Display Controller KMS

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On Wed, Dec 11, 2024 at 03:43:20PM +0800, Liu Ying wrote:
> On 12/10/2024, Dmitry Baryshkov wrote:
> > On Mon, Dec 09, 2024 at 11:39:16AM +0800, Liu Ying wrote:
> >> i.MX8qxp Display Controller(DC) is comprised of three main components that
> >> include a blit engine for 2D graphics accelerations, display controller for
> >> display output processing, as well as a command sequencer.  Add kernel
> >> mode setting support for the display controller part with two CRTCs and
> >> two primary planes(backed by FetchLayer and FetchWarp respectively).  The
> >> registers of the display controller are accessed without command sequencer
> >> involved, instead just by using CPU.  The command sequencer is supposed to
> >> be used by the blit engine.
> >>
> >> Signed-off-by: Liu Ying <victor.liu@xxxxxxx>
> >> ---
> >> v6:
> >> * No change.
> >>
> >> v5:
> >> * Replace .remove_new with .remove in dc-drv.c. (Uwe)
> >>
> >> v4:
> >> * Move dc_fg_displaymode(), dc_fg_panic_displaymode() and dc_lb_blendcontrol()
> >>   function calls from KMS routine to initialization stage. (Dmitry)
> >> * Drop dc-crtc.h and dc-plane.h header files and move relevant defines to
> >>   appropriate .h header files or .c source files. (Dmitry)
> >> * Drop futile "else" clause from dc_crtc_common_irq_handler(). (Dmitry)
> >> * Drop dc_drm->pe_rpm_count. (Dmitry)
> >> * Drop DC_{CRTCS,ENCODERS,PRIMARYS} macros and only use DC_DISPLAYS. (Dmitry)
> >> * Drop drmm_kcalloc() function call to allocate an array for storing IRQs.
> >>   Instead, put it in struct dc_crtc.  (Dmitry)
> >> * Call devm_request_irq() to request IRQs, instead of using drmm action.
> >>   (Dmitry)
> >> * Call devm_drm_of_get_bridge() to find the next bridge. (Dmitry)
> >> * Select DRM_CLIENT_SELECTION due to rebase.
> >> * Select the missing DRM_DISPLAY_HELPER and DRM_BRIDGE_CONNECTOR.
> >> * Use DRM_FBDEV_DMA_DRIVER_OPS due to rebase.
> >> * Replace drm_fbdev_dma_setup() with drm_client_setup_with_fourcc() due to
> >>   rebase.
> >> * Replace drmm_add_action_or_reset() with devm_add_action_or_reset() to
> >>   register dc_drm_component_unbind_all() action.
> >> * Request interrupts in dc_crtc_post_init() after encoder initialization to
> >>   make sure next bridge is found first.
> >>
> >> v3:
> >> * No change.
> >>
> >> v2:
> >> * Find next bridge from TCon's port.
> >> * Drop drm/drm_module.h include from dc-drv.c.
> >>
> >>  drivers/gpu/drm/imx/dc/Kconfig    |   5 +
> >>  drivers/gpu/drm/imx/dc/Makefile   |   5 +-
> >>  drivers/gpu/drm/imx/dc/dc-crtc.c  | 558 ++++++++++++++++++++++++++++++
> >>  drivers/gpu/drm/imx/dc/dc-de.h    |   3 +
> >>  drivers/gpu/drm/imx/dc/dc-drv.c   | 244 +++++++++++++
> >>  drivers/gpu/drm/imx/dc/dc-drv.h   |  19 +
> >>  drivers/gpu/drm/imx/dc/dc-kms.c   | 143 ++++++++
> >>  drivers/gpu/drm/imx/dc/dc-kms.h   |  58 ++++
> >>  drivers/gpu/drm/imx/dc/dc-plane.c | 241 +++++++++++++
> >>  9 files changed, 1274 insertions(+), 2 deletions(-)
> >>  create mode 100644 drivers/gpu/drm/imx/dc/dc-crtc.c
> >>  create mode 100644 drivers/gpu/drm/imx/dc/dc-kms.c
> >>  create mode 100644 drivers/gpu/drm/imx/dc/dc-kms.h
> >>  create mode 100644 drivers/gpu/drm/imx/dc/dc-plane.c
> >>
> >> diff --git a/drivers/gpu/drm/imx/dc/Kconfig b/drivers/gpu/drm/imx/dc/Kconfig
> >> index 1fc84c7475de..415993207f2e 100644
> >> --- a/drivers/gpu/drm/imx/dc/Kconfig
> >> +++ b/drivers/gpu/drm/imx/dc/Kconfig
> >> @@ -1,6 +1,11 @@
> >>  config DRM_IMX8_DC
> >>  	tristate "Freescale i.MX8 Display Controller Graphics"
> >>  	depends on DRM && COMMON_CLK && OF && (ARCH_MXC || COMPILE_TEST)
> >> +	select DRM_CLIENT_SELECTION
> >> +	select DRM_GEM_DMA_HELPER
> >> +	select DRM_KMS_HELPER
> >> +	select DRM_DISPLAY_HELPER
> >> +	select DRM_BRIDGE_CONNECTOR
> >>  	select GENERIC_IRQ_CHIP
> >>  	select REGMAP
> >>  	select REGMAP_MMIO
> >> diff --git a/drivers/gpu/drm/imx/dc/Makefile b/drivers/gpu/drm/imx/dc/Makefile
> >> index 1ce3e8a8db22..b9d33c074984 100644
> >> --- a/drivers/gpu/drm/imx/dc/Makefile
> >> +++ b/drivers/gpu/drm/imx/dc/Makefile
> >> @@ -1,6 +1,7 @@
> >>  # SPDX-License-Identifier: GPL-2.0
> >>  
> >> -imx8-dc-drm-objs := dc-cf.o dc-de.o dc-drv.o dc-ed.o dc-fg.o dc-fl.o dc-fu.o \
> >> -		    dc-fw.o dc-ic.o dc-lb.o dc-pe.o dc-tc.o
> >> +imx8-dc-drm-objs := dc-cf.o dc-crtc.o dc-de.o dc-drv.o dc-ed.o dc-fg.o dc-fl.o \
> >> +		    dc-fu.o dc-fw.o dc-ic.o dc-kms.o dc-lb.o dc-pe.o \
> >> +		    dc-plane.o dc-tc.o
> >>  
> >>  obj-$(CONFIG_DRM_IMX8_DC) += imx8-dc-drm.o
> >> diff --git a/drivers/gpu/drm/imx/dc/dc-crtc.c b/drivers/gpu/drm/imx/dc/dc-crtc.c
> >> new file mode 100644
> >> index 000000000000..fd6daa1807d8
> >> --- /dev/null
> >> +++ b/drivers/gpu/drm/imx/dc/dc-crtc.c
> >> @@ -0,0 +1,558 @@
> >> +// SPDX-License-Identifier: GPL-2.0+
> >> +/*
> >> + * Copyright 2024 NXP
> >> + */
> >> +
> >> +#include <linux/completion.h>
> >> +#include <linux/container_of.h>
> >> +#include <linux/interrupt.h>
> >> +#include <linux/irqreturn.h>
> >> +#include <linux/pm_runtime.h>
> >> +#include <linux/spinlock.h>
> >> +
> >> +#include <drm/drm_atomic.h>
> >> +#include <drm/drm_atomic_helper.h>
> >> +#include <drm/drm_atomic_state_helper.h>
> >> +#include <drm/drm_crtc.h>
> >> +#include <drm/drm_device.h>
> >> +#include <drm/drm_drv.h>
> >> +#include <drm/drm_modes.h>
> >> +#include <drm/drm_modeset_helper_vtables.h>
> >> +#include <drm/drm_plane.h>
> >> +#include <drm/drm_print.h>
> >> +#include <drm/drm_vblank.h>
> >> +
> >> +#include "dc-de.h"
> >> +#include "dc-drv.h"
> >> +#include "dc-kms.h"
> >> +#include "dc-pe.h"
> >> +
> >> +#define dc_crtc_dbg(crtc, fmt, ...)					\
> >> +do {									\
> >> +	typeof(crtc) _crtc = (crtc);					\
> > 
> > Use exact type instead of typeof.
> 
> Will do.
> 
> > 
> >> +	drm_dbg_kms(_crtc->dev, "[CRTC:%d:%s] " fmt,			\
> >> +		    _crtc->base.id, _crtc->name, ##__VA_ARGS__);	\
> >> +} while (0)
> >> +
> >> +#define dc_crtc_err(crtc, fmt, ...)					\
> >> +do {									\
> >> +	typeof(crtc) _crtc = (crtc);					\
> >> +	drm_err(_crtc->dev, "[CRTC:%d:%s] " fmt,			\
> >> +		_crtc->base.id, _crtc->name, ##__VA_ARGS__);		\
> >> +} while (0)
> >> +
> >> +#define DC_CRTC_WAIT_FOR_COMPLETION_TIMEOUT(c)				\
> >> +do {									\
> >> +	unsigned long ret;						\
> >> +	ret = wait_for_completion_timeout(&dc_crtc->c, HZ);		\
> >> +	if (ret == 0)							\
> >> +		dc_crtc_err(crtc, "%s: wait for " #c " timeout\n",	\
> >> +							__func__);	\
> >> +} while (0)
> >> +
> >> +#define DC_CRTC_CHECK_FRAMEGEN_FIFO(fg)					\
> >> +do {									\
> >> +	typeof(fg) _fg = (fg);						\
> >> +	if (dc_fg_secondary_requests_to_read_empty_fifo(_fg)) {		\
> >> +		dc_fg_secondary_clear_channel_status(_fg);		\
> >> +		dc_crtc_err(crtc, "%s: FrameGen FIFO empty\n",		\
> >> +							__func__);	\
> >> +	}								\
> >> +} while (0)
> >> +
> >> +#define DC_CRTC_WAIT_FOR_FRAMEGEN_SECONDARY_SYNCUP(fg)			\
> >> +do {									\
> >> +	if (dc_fg_wait_for_secondary_syncup(fg))			\
> >> +		dc_crtc_err(crtc,					\
> >> +			"%s: FrameGen secondary channel isn't syncup\n",\
> >> +							__func__);	\
> >> +} while (0)
> >> +
> >> +static inline struct dc_crtc *to_dc_crtc(struct drm_crtc *crtc)
> >> +{
> >> +	return container_of(crtc, struct dc_crtc, base);
> >> +}
> >> +
> >> +static u32 dc_crtc_get_vblank_counter(struct drm_crtc *crtc)
> >> +{
> >> +	struct dc_crtc *dc_crtc = to_dc_crtc(crtc);
> >> +
> >> +	return dc_fg_get_frame_index(dc_crtc->fg);
> >> +}
> >> +
> >> +static int dc_crtc_enable_vblank(struct drm_crtc *crtc)
> >> +{
> >> +	struct dc_crtc *dc_crtc = to_dc_crtc(crtc);
> >> +
> >> +	enable_irq(dc_crtc->irq_dec_framecomplete);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static void dc_crtc_disable_vblank(struct drm_crtc *crtc)
> >> +{
> >> +	struct dc_crtc *dc_crtc = to_dc_crtc(crtc);
> >> +
> >> +	disable_irq_nosync(dc_crtc->irq_dec_framecomplete);
> > 
> > Why is it _nosync?
> 
> Because disable_irq() can only be called from preemptible code according to
> it's kerneldoc. If I use disable_irq() here, I get this with
> CONFIG_DEBUG_ATOMIC_SLEEP enabled:

Please add a one-line comment, like "nosync because of the atomic
context"

> 
> [   50.607503] BUG: sleeping function called from invalid context at kernel/irq/manage.c:738
> [   50.615691] in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 0, name: swapper/0
> [   50.623527] preempt_count: 10003, expected: 0
> [   50.627888] RCU nest depth: 0, expected: 0
> [   50.631993] CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.13.0-rc2-next-20241209-00026-g800cb5b7df74 #1407
> [   50.642092] Hardware name: Freescale i.MX8QXP MEK (DT)
> [   50.647237] Call trace:
> [   50.649687]  show_stack+0x18/0x24 (C)
> [   50.653369]  dump_stack_lvl+0x80/0xb4
> [   50.657043]  dump_stack+0x18/0x24
> [   50.660370]  __might_resched+0x114/0x170
> [   50.664306]  __might_sleep+0x48/0x98
> [   50.667894]  disable_irq+0x24/0x60
> [   50.671308]  dc_crtc_disable_vblank+0x14/0x20 [imx8_dc_drm]
> [   50.676912]  drm_vblank_disable_and_save+0xc0/0x108 [drm]
> [   50.682533]  vblank_disable_fn+0x78/0x9c [drm]
> [   50.687146]  drm_handle_vblank+0x238/0x2e8 [drm]
> [   50.691932]  drm_crtc_handle_vblank+0x1c/0x28 [drm]
> [   50.696980]  dc_crtc_irq_handler_dec_framecomplete+0x1c/0x6c [imx8_dc_drm]
> [   50.703886]  __handle_irq_event_percpu+0x60/0x14c
> [   50.708604]  handle_irq_event+0x4c/0xac
> [   50.712443]  handle_level_irq+0xc0/0x1b0
> [   50.716379]  generic_handle_irq+0x34/0x4c
> [   50.720392]  dc_ic_irq_handler+0x128/0x160 [imx8_dc_drm]
> [   50.725727]  generic_handle_domain_irq+0x2c/0x44
> [   50.730357]  imx_irqsteer_irq_handler+0xc0/0x1a0
> [   50.734987]  generic_handle_domain_irq+0x2c/0x44
> [   50.739609]  gic_handle_irq+0x4c/0x114
> [   50.743362]  call_on_irq_stack+0x24/0x4c
> [   50.747298]  do_interrupt_handler+0x80/0x84
> [   50.751494]  el1_interrupt+0x34/0x68
> [   50.755082]  el1h_64_irq_handler+0x18/0x24
> [   50.759191]  el1h_64_irq+0x6c/0x70
> [   50.762597]  default_idle_call+0x28/0x3c (P)
> [   50.766879]  default_idle_call+0x24/0x3c (L)
> [   50.771163]  do_idle+0x200/0x25c
> [   50.774403]  cpu_startup_entry+0x34/0x3c
> [   50.778338]  kernel_init+0x0/0x1d8
> [   50.781752]  start_kernel+0x5c4/0x70c
> [   50.785427]  __primary_switched+0x88/0x90
> 
> > 
> >> +}
> >> +
> >> +static irqreturn_t
> >> +dc_crtc_dec_framecomplete_irq_handler(int irq, void *dev_id)
> >> +{
> >> +	struct dc_crtc *dc_crtc = dev_id;
> >> +	struct drm_crtc *crtc = &dc_crtc->base;
> >> +	unsigned long flags;
> >> +
> >> +	drm_crtc_handle_vblank(crtc);
> >> +
> >> +	spin_lock_irqsave(&crtc->dev->event_lock, flags);
> >> +	if (dc_crtc->event) {
> >> +		drm_crtc_send_vblank_event(crtc, dc_crtc->event);
> >> +		dc_crtc->event = NULL;
> >> +		drm_crtc_vblank_put(crtc);
> >> +	}
> >> +	spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
> >> +
> >> +	return IRQ_HANDLED;
> >> +}
> >> +
> >> +static irqreturn_t dc_crtc_common_irq_handler(int irq, void *dev_id)
> >> +{
> >> +	struct dc_crtc *dc_crtc = dev_id;
> >> +
> >> +	if (irq == dc_crtc->irq_dec_seqcomplete)
> >> +		complete(&dc_crtc->dec_seqcomplete_done);
> >> +	else if (irq == dc_crtc->irq_dec_shdld)
> >> +		complete(&dc_crtc->dec_shdld_done);
> >> +	else if (irq == dc_crtc->irq_ed_cont_shdld)
> >> +		complete(&dc_crtc->ed_cont_shdld_done);
> >> +	else if (irq == dc_crtc->irq_ed_safe_shdld)
> >> +		complete(&dc_crtc->ed_safe_shdld_done);
> > 
> > Is there any reason to have a single multiplex handler instead of having
> > 4 separate handlers, each doing one simple thing?
> 
> Just thought that one irq handler is feasible to implement the common
> handling logic. It's also ok to use 4 separate handlers with a little
> performance improvement. I may change to use 4 separate handlers by
> introducing a DEFINE_DC_CRTC_IRQ_HANDLER() marco.

Just define them one by one, there is no need for a macro.

> 
> > 
> >> +
> >> +	return IRQ_HANDLED;
> >> +}
> >> +
> >> +static const struct drm_crtc_funcs dc_crtc_funcs = {
> >> +	.reset			= drm_atomic_helper_crtc_reset,
> >> +	.destroy		= drm_crtc_cleanup,
> >> +	.set_config		= drm_atomic_helper_set_config,
> >> +	.page_flip		= drm_atomic_helper_page_flip,
> >> +	.atomic_duplicate_state	= drm_atomic_helper_crtc_duplicate_state,
> >> +	.atomic_destroy_state	= drm_atomic_helper_crtc_destroy_state,
> >> +	.get_vblank_counter	= dc_crtc_get_vblank_counter,
> >> +	.enable_vblank		= dc_crtc_enable_vblank,
> >> +	.disable_vblank		= dc_crtc_disable_vblank,
> >> +	.get_vblank_timestamp	= drm_crtc_vblank_helper_get_vblank_timestamp,
> >> +};
> >> +
> >> +static void dc_crtc_queue_state_event(struct drm_crtc_state *crtc_state)
> >> +{
> >> +	struct drm_crtc *crtc = crtc_state->crtc;
> >> +	struct dc_crtc *dc_crtc = to_dc_crtc(crtc);
> >> +
> >> +	spin_lock_irq(&crtc->dev->event_lock);
> >> +	if (crtc_state->event) {
> >> +		WARN_ON(drm_crtc_vblank_get(crtc));
> >> +		WARN_ON(dc_crtc->event);
> >> +		dc_crtc->event = crtc_state->event;
> >> +		crtc_state->event = NULL;
> >> +	}
> >> +	spin_unlock_irq(&crtc->dev->event_lock);
> >> +}
> >> +
> >> +static enum drm_mode_status
> >> +dc_crtc_check_clock(struct dc_crtc *dc_crtc, int clk_khz)
> >> +{
> >> +	return dc_fg_check_clock(dc_crtc->fg, clk_khz);
> >> +}
> > 
> > inline
> 
> Will do.
> 
> > 
> >> +
> >> +static enum drm_mode_status
> >> +dc_crtc_mode_valid(struct drm_crtc *crtc, const struct drm_display_mode *mode)
> >> +{
> >> +	struct dc_crtc *dc_crtc = to_dc_crtc(crtc);
> >> +	enum drm_mode_status status;
> >> +
> >> +	status = dc_crtc_check_clock(dc_crtc, mode->clock);
> >> +	if (status != MODE_OK)
> >> +		return status;
> >> +
> >> +	if (mode->crtc_clock > DC_FRAMEGEN_MAX_CLOCK_KHZ)
> >> +		return MODE_CLOCK_HIGH;
> >> +
> >> +	return MODE_OK;
> >> +}
> >> +
> >> +static int
> >> +dc_crtc_atomic_check(struct drm_crtc *crtc, struct drm_atomic_state *state)
> >> +{
> >> +	struct drm_crtc_state *new_crtc_state =
> >> +				drm_atomic_get_new_crtc_state(state, crtc);
> >> +	struct drm_display_mode *adj = &new_crtc_state->adjusted_mode;
> >> +	struct dc_crtc *dc_crtc = to_dc_crtc(crtc);
> >> +	enum drm_mode_status status;
> >> +
> >> +	status = dc_crtc_check_clock(dc_crtc, adj->clock);
> >> +	if (status != MODE_OK)
> >> +		return -EINVAL;
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static void
> >> +dc_crtc_atomic_begin(struct drm_crtc *crtc, struct drm_atomic_state *state)
> >> +{
> >> +	struct drm_crtc_state *new_crtc_state =
> >> +				drm_atomic_get_new_crtc_state(state, crtc);
> >> +	struct dc_crtc *dc_crtc = to_dc_crtc(crtc);
> >> +	int idx, ret;
> >> +
> >> +	if (!drm_atomic_crtc_needs_modeset(new_crtc_state) ||
> >> +	    !new_crtc_state->active)
> >> +		return;
> >> +
> >> +	if (!drm_dev_enter(crtc->dev, &idx))
> >> +		return;
> >> +
> >> +	/* request pixel engine power-on when CRTC starts to be active */
> >> +	ret = pm_runtime_resume_and_get(dc_crtc->pe->dev);
> >> +	if (ret)
> >> +		dc_crtc_err(crtc, "failed to get DC pixel engine RPM: %d\n",
> >> +			    ret);
> >> +
> >> +	drm_dev_exit(idx);
> >> +}
> >> +
> >> +static void
> >> +dc_crtc_atomic_flush(struct drm_crtc *crtc, struct drm_atomic_state *state)
> >> +{
> >> +	struct drm_crtc_state *old_crtc_state =
> >> +				drm_atomic_get_old_crtc_state(state, crtc);
> >> +	struct drm_crtc_state *new_crtc_state =
> >> +				drm_atomic_get_new_crtc_state(state, crtc);
> >> +	struct dc_crtc *dc_crtc = to_dc_crtc(crtc);
> >> +	int idx;
> >> +
> >> +	if (drm_atomic_crtc_needs_modeset(new_crtc_state) ||
> >> +	    (!old_crtc_state->active && !new_crtc_state->active))
> >> +		return;
> >> +
> >> +	if (!drm_dev_enter(crtc->dev, &idx))
> >> +		goto out;
> >> +
> >> +	enable_irq(dc_crtc->irq_ed_cont_shdld);
> >> +
> >> +	/* flush plane update out to display */
> >> +	dc_ed_pec_sync_trigger(dc_crtc->ed_cont);
> >> +
> >> +	DC_CRTC_WAIT_FOR_COMPLETION_TIMEOUT(ed_cont_shdld_done);
> >> +
> >> +	disable_irq(dc_crtc->irq_ed_cont_shdld);
> >> +
> >> +	DC_CRTC_CHECK_FRAMEGEN_FIFO(dc_crtc->fg);
> >> +
> >> +	drm_dev_exit(idx);
> >> +
> >> +out:
> >> +	dc_crtc_queue_state_event(new_crtc_state);
> >> +}
> >> +
> >> +static void
> >> +dc_crtc_atomic_enable(struct drm_crtc *crtc, struct drm_atomic_state *state)
> >> +{
> >> +	struct drm_crtc_state *new_crtc_state =
> >> +				drm_atomic_get_new_crtc_state(state, crtc);
> >> +	struct drm_display_mode *adj = &new_crtc_state->adjusted_mode;
> >> +	struct dc_crtc *dc_crtc = to_dc_crtc(crtc);
> >> +	enum dc_link_id cf_link;
> >> +	int idx, ret;
> >> +
> >> +	dc_crtc_dbg(crtc, "mode " DRM_MODE_FMT "\n", DRM_MODE_ARG(adj));
> >> +
> >> +	drm_crtc_vblank_on(crtc);
> >> +
> >> +	if (!drm_dev_enter(crtc->dev, &idx))
> >> +		goto out;
> >> +
> >> +	/* request display engine power-on when CRTC is enabled */
> >> +	ret = pm_runtime_resume_and_get(dc_crtc->de->dev);
> >> +	if (ret < 0)
> >> +		dc_crtc_err(crtc, "failed to get DC display engine RPM: %d\n",
> >> +			    ret);
> >> +
> >> +	enable_irq(dc_crtc->irq_dec_shdld);
> >> +	enable_irq(dc_crtc->irq_ed_cont_shdld);
> >> +	enable_irq(dc_crtc->irq_ed_safe_shdld);
> >> +
> >> +	dc_fg_cfg_videomode(dc_crtc->fg, adj);
> >> +
> >> +	dc_cf_framedimensions(dc_crtc->cf_cont,
> >> +			      adj->crtc_hdisplay, adj->crtc_vdisplay);
> >> +	dc_cf_framedimensions(dc_crtc->cf_safe,
> >> +			      adj->crtc_hdisplay, adj->crtc_vdisplay);
> >> +
> >> +	/* constframe in safety stream shows blue frame */
> >> +	dc_cf_constantcolor_blue(dc_crtc->cf_safe);
> >> +	cf_link = dc_cf_get_link_id(dc_crtc->cf_safe);
> >> +	dc_ed_pec_src_sel(dc_crtc->ed_safe, cf_link);
> >> +
> >> +	/* show CRTC background if no plane is enabled */
> >> +	if (new_crtc_state->plane_mask == 0) {
> >> +		/* constframe in content stream shows black frame */
> >> +		dc_cf_constantcolor_black(dc_crtc->cf_cont);
> >> +
> >> +		cf_link = dc_cf_get_link_id(dc_crtc->cf_cont);
> >> +		dc_ed_pec_src_sel(dc_crtc->ed_cont, cf_link);
> >> +	}
> >> +
> >> +	dc_fg_enable_clock(dc_crtc->fg);
> >> +	dc_ed_pec_sync_trigger(dc_crtc->ed_cont);
> >> +	dc_ed_pec_sync_trigger(dc_crtc->ed_safe);
> >> +	dc_fg_shdtokgen(dc_crtc->fg);
> >> +	dc_fg_enable(dc_crtc->fg);
> >> +
> >> +	DC_CRTC_WAIT_FOR_COMPLETION_TIMEOUT(ed_safe_shdld_done);
> >> +	DC_CRTC_WAIT_FOR_COMPLETION_TIMEOUT(ed_cont_shdld_done);
> >> +	DC_CRTC_WAIT_FOR_COMPLETION_TIMEOUT(dec_shdld_done);
> >> +
> >> +	disable_irq(dc_crtc->irq_ed_safe_shdld);
> >> +	disable_irq(dc_crtc->irq_ed_cont_shdld);
> >> +	disable_irq(dc_crtc->irq_dec_shdld);
> >> +
> >> +	DC_CRTC_WAIT_FOR_FRAMEGEN_SECONDARY_SYNCUP(dc_crtc->fg);
> >> +
> >> +	DC_CRTC_CHECK_FRAMEGEN_FIFO(dc_crtc->fg);
> >> +
> >> +	drm_dev_exit(idx);
> >> +
> >> +out:
> >> +	dc_crtc_queue_state_event(new_crtc_state);
> >> +}
> >> +
> >> +static void
> >> +dc_crtc_atomic_disable(struct drm_crtc *crtc, struct drm_atomic_state *state)
> >> +{
> >> +	struct drm_crtc_state *new_crtc_state =
> >> +				drm_atomic_get_new_crtc_state(state, crtc);
> >> +	struct dc_crtc *dc_crtc = to_dc_crtc(crtc);
> >> +	int idx, ret;
> >> +
> >> +	if (!drm_dev_enter(crtc->dev, &idx))
> >> +		goto out;
> >> +
> >> +	enable_irq(dc_crtc->irq_dec_seqcomplete);
> >> +	dc_fg_disable(dc_crtc->fg);
> >> +	DC_CRTC_WAIT_FOR_COMPLETION_TIMEOUT(dec_seqcomplete_done);
> >> +	disable_irq(dc_crtc->irq_dec_seqcomplete);
> >> +
> >> +	dc_fg_disable_clock(dc_crtc->fg);
> >> +
> >> +	/* request pixel engine power-off as plane is off too */
> >> +	ret = pm_runtime_put(dc_crtc->pe->dev);
> >> +	if (ret)
> >> +		dc_crtc_err(crtc, "failed to put DC pixel engine RPM: %d\n",
> >> +			    ret);
> >> +
> >> +	/* request display engine power-off when CRTC is disabled */
> >> +	ret = pm_runtime_put(dc_crtc->de->dev);
> > 
> > Can this be expressed as a devlink between PE and DE?
> 
> Looking at struct dc_{pe,de}, PE and DE are not dependent with each other,
> i.e., no consumer/supplier relationship(note that blit engine in PE can work
> by itself without DE) between them. So, it doesn't look right to link the two
> devices.

Ack

> 
> > 
> >> +	if (ret < 0)
> >> +		dc_crtc_err(crtc, "failed to put DC display engine RPM: %d\n",
> >> +			    ret);
> >> +
> >> +	drm_dev_exit(idx);
> >> +
> >> +out:
> >> +	drm_crtc_vblank_off(crtc);
> >> +
> >> +	spin_lock_irq(&crtc->dev->event_lock);
> >> +	if (new_crtc_state->event && !new_crtc_state->active) {
> >> +		drm_crtc_send_vblank_event(crtc, new_crtc_state->event);
> >> +		new_crtc_state->event = NULL;
> >> +	}
> >> +	spin_unlock_irq(&crtc->dev->event_lock);
> >> +}
> >> +
> >> +void dc_crtc_disable_at_unbind(struct drm_crtc *crtc)
> >> +{
> >> +	struct dc_crtc *dc_crtc = to_dc_crtc(crtc);
> >> +	int ret;
> >> +
> >> +	if (!dc_fg_wait_for_frame_index_moving(dc_crtc->fg))
> >> +		return;
> >> +
> >> +	dc_fg_disable_clock(dc_crtc->fg);
> >> +
> >> +	if (pm_runtime_active(dc_crtc->pe->dev)) {
> >> +		ret = pm_runtime_put_sync(dc_crtc->pe->dev);
> >> +		if (ret)
> >> +			dc_crtc_err(crtc, "failed to put DC pixel engine RPM: %d\n",
> >> +				    ret);
> >> +	}
> >> +
> >> +	ret = pm_runtime_put_sync(dc_crtc->de->dev);
> >> +	if (ret < 0)
> >> +		dc_crtc_err(crtc, "failed to put DC display engine RPM: %d\n",
> >> +			    ret);
> >> +}
> >> +
> >> +static bool dc_crtc_get_scanout_position(struct drm_crtc *crtc,
> >> +					 bool in_vblank_irq,
> >> +					 int *vpos, int *hpos,
> >> +					 ktime_t *stime, ktime_t *etime,
> >> +					 const struct drm_display_mode *mode)
> >> +{
> >> +	struct dc_crtc *dc_crtc = to_dc_crtc(crtc);
> >> +	int vdisplay = mode->crtc_vdisplay;
> >> +	int vtotal = mode->crtc_vtotal;
> >> +	bool reliable;
> >> +	int line;
> >> +	int idx;
> >> +
> >> +	if (stime)
> >> +		*stime = ktime_get();
> >> +
> >> +	if (!drm_dev_enter(crtc->dev, &idx)) {
> >> +		reliable = false;
> >> +		*vpos = 0;
> >> +		*hpos = 0;
> >> +		goto out;
> >> +	}
> >> +
> >> +	/* line index starts with 0 for the first active output line */
> >> +	line = dc_fg_get_line_index(dc_crtc->fg);
> >> +
> >> +	if (line < vdisplay)
> >> +		/* active scanout area - positive */
> >> +		*vpos = line + 1;
> >> +	else
> >> +		/* inside vblank - negative */
> >> +		*vpos = line - (vtotal - 1);
> >> +
> >> +	*hpos = 0;
> >> +
> >> +	reliable = true;
> >> +
> >> +	drm_dev_exit(idx);
> >> +out:
> >> +	if (etime)
> >> +		*etime = ktime_get();
> >> +
> >> +	return reliable;
> >> +}
> >> +
> >> +static const struct drm_crtc_helper_funcs dc_helper_funcs = {
> >> +	.mode_valid		= dc_crtc_mode_valid,
> >> +	.atomic_check		= dc_crtc_atomic_check,
> >> +	.atomic_begin		= dc_crtc_atomic_begin,
> >> +	.atomic_flush		= dc_crtc_atomic_flush,
> >> +	.atomic_enable		= dc_crtc_atomic_enable,
> >> +	.atomic_disable		= dc_crtc_atomic_disable,
> >> +	.get_scanout_position	= dc_crtc_get_scanout_position,
> >> +};
> >> +
> >> +static int dc_crtc_request_irqs(struct drm_device *drm, struct dc_crtc *dc_crtc)
> >> +{
> >> +	struct {
> >> +		struct device *dev;
> >> +		unsigned int irq;
> >> +		irqreturn_t (*irq_handler)(int irq, void *dev_id);
> >> +	} irqs[DC_CRTC_IRQS] = {
> >> +		{
> >> +			dc_crtc->de->dev,
> >> +			dc_crtc->irq_dec_framecomplete,
> >> +			dc_crtc_dec_framecomplete_irq_handler,
> >> +		}, {
> >> +			dc_crtc->de->dev,
> >> +			dc_crtc->irq_dec_seqcomplete,
> >> +			dc_crtc_common_irq_handler,
> >> +		}, {
> >> +			dc_crtc->de->dev,
> >> +			dc_crtc->irq_dec_shdld,
> >> +			dc_crtc_common_irq_handler,
> >> +		}, {
> >> +			dc_crtc->ed_cont->dev,
> >> +			dc_crtc->irq_ed_cont_shdld,
> >> +			dc_crtc_common_irq_handler,
> >> +		}, {
> >> +			dc_crtc->ed_safe->dev,
> >> +			dc_crtc->irq_ed_safe_shdld,
> >> +			dc_crtc_common_irq_handler,
> >> +		},
> >> +	};
> >> +	int i, ret;
> >> +
> >> +	for (i = 0; i < DC_CRTC_IRQS; i++) {
> >> +		struct dc_crtc_irq *irq = &dc_crtc->irqs[i];
> >> +
> >> +		ret = devm_request_irq(irqs[i].dev, irqs[i].irq,
> >> +				       irqs[i].irq_handler, IRQF_NO_AUTOEN,
> >> +				       dev_name(irqs[i].dev), dc_crtc);
> >> +		if (ret) {
> >> +			dev_err(irqs[i].dev, "failed to request irq(%u): %d\n",
> >> +				irqs[i].irq, ret);
> >> +			return ret;
> >> +		}
> >> +
> >> +		irq->dc_crtc = dc_crtc;
> >> +		irq->irq = irqs[i].irq;
> >> +	}
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +int dc_crtc_init(struct dc_drm_device *dc_drm, int crtc_index)
> >> +{
> >> +	struct dc_crtc *dc_crtc = &dc_drm->dc_crtc[crtc_index];
> >> +	struct drm_device *drm = &dc_drm->base;
> >> +	struct dc_de *de = dc_drm->de[crtc_index];
> >> +	struct dc_pe *pe = dc_drm->pe;
> >> +	struct dc_plane *dc_primary;
> >> +	int ret;
> >> +
> >> +	dc_crtc->de = de;
> >> +	dc_crtc->pe = pe;
> >> +
> >> +	init_completion(&dc_crtc->dec_seqcomplete_done);
> >> +	init_completion(&dc_crtc->dec_shdld_done);
> >> +	init_completion(&dc_crtc->ed_cont_shdld_done);
> >> +	init_completion(&dc_crtc->ed_safe_shdld_done);
> >> +
> >> +	dc_crtc->cf_cont = pe->cf_cont[crtc_index];
> >> +	dc_crtc->cf_safe = pe->cf_safe[crtc_index];
> >> +	dc_crtc->ed_cont = pe->ed_cont[crtc_index];
> >> +	dc_crtc->ed_safe = pe->ed_safe[crtc_index];
> >> +	dc_crtc->fg = de->fg;
> >> +
> >> +	dc_crtc->irq_dec_framecomplete = de->irq_framecomplete;
> >> +	dc_crtc->irq_dec_seqcomplete = de->irq_seqcomplete;
> >> +	dc_crtc->irq_dec_shdld = de->irq_shdld;
> >> +	dc_crtc->irq_ed_safe_shdld = dc_crtc->ed_safe->irq_shdld;
> >> +	dc_crtc->irq_ed_cont_shdld = dc_crtc->ed_cont->irq_shdld;
> >> +
> >> +	dc_primary = &dc_drm->dc_primary[crtc_index];
> >> +	ret = dc_plane_init(dc_drm, dc_primary);
> >> +	if (ret) {
> >> +		dev_err(drm->dev,
> >> +			"failed to init primary plane for display engine%u: %d\n",
> >> +			de->id, ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	drm_crtc_helper_add(&dc_crtc->base, &dc_helper_funcs);
> >> +
> >> +	ret = drm_crtc_init_with_planes(drm, &dc_crtc->base, &dc_primary->base,
> >> +					NULL, &dc_crtc_funcs, NULL);
> >> +	if (ret)
> >> +		dev_err(drm->dev,
> >> +			"failed to add CRTC for display engine%u: %d\n",
> >> +			de->id, ret);
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +int dc_crtc_post_init(struct dc_drm_device *dc_drm, int crtc_index)
> >> +{
> >> +	struct dc_crtc *dc_crtc = &dc_drm->dc_crtc[crtc_index];
> >> +	struct drm_device *drm = &dc_drm->base;
> >> +
> >> +	return dc_crtc_request_irqs(drm, dc_crtc);
> >> +}
> >> diff --git a/drivers/gpu/drm/imx/dc/dc-de.h b/drivers/gpu/drm/imx/dc/dc-de.h
> >> index 17a44362118e..8a7b6c03a222 100644
> >> --- a/drivers/gpu/drm/imx/dc/dc-de.h
> >> +++ b/drivers/gpu/drm/imx/dc/dc-de.h
> >> @@ -13,6 +13,9 @@
> >>  
> >>  #define DC_DISPLAYS	2
> >>  
> >> +#define DC_FRAMEGEN_MAX_FRAME_INDEX	0x3ffff
> >> +#define DC_FRAMEGEN_MAX_CLOCK_KHZ	300000
> >> +
> >>  struct dc_fg {
> >>  	struct device *dev;
> >>  	struct regmap *reg;
> >> diff --git a/drivers/gpu/drm/imx/dc/dc-drv.c b/drivers/gpu/drm/imx/dc/dc-drv.c
> >> index fd68861f770a..1e4b8afa3eec 100644
> >> --- a/drivers/gpu/drm/imx/dc/dc-drv.c
> >> +++ b/drivers/gpu/drm/imx/dc/dc-drv.c
> >> @@ -3,11 +3,254 @@
> >>   * Copyright 2024 NXP
> >>   */
> >>  
> >> +#include <linux/clk.h>
> >> +#include <linux/component.h>
> >> +#include <linux/device.h>
> >> +#include <linux/dma-mapping.h>
> >> +#include <linux/mod_devicetable.h>
> >>  #include <linux/module.h>
> >> +#include <linux/of.h>
> >> +#include <linux/of_platform.h>
> >>  #include <linux/platform_device.h>
> >> +#include <linux/pm.h>
> >> +#include <linux/pm_runtime.h>
> >>  
> >> +#include <drm/drm_atomic_helper.h>
> >> +#include <drm/drm_client_setup.h>
> >> +#include <drm/drm_crtc.h>
> >> +#include <drm/drm_drv.h>
> >> +#include <drm/drm_fbdev_dma.h>
> >> +#include <drm/drm_fourcc.h>
> >> +#include <drm/drm_gem_dma_helper.h>
> >> +#include <drm/drm_managed.h>
> >> +#include <drm/drm_modeset_helper.h>
> >> +#include <drm/drm_of.h>
> >> +
> >> +#include "dc-de.h"
> >>  #include "dc-drv.h"
> >>  
> >> +struct dc_priv {
> >> +	struct drm_device *drm;
> >> +	struct clk *clk_cfg;
> >> +};
> >> +
> >> +DEFINE_DRM_GEM_DMA_FOPS(dc_drm_driver_fops);
> >> +
> >> +static struct drm_driver dc_drm_driver = {
> >> +	.driver_features = DRIVER_MODESET | DRIVER_GEM | DRIVER_ATOMIC,
> >> +	DRM_GEM_DMA_DRIVER_OPS,
> >> +	DRM_FBDEV_DMA_DRIVER_OPS,
> >> +	.fops = &dc_drm_driver_fops,
> >> +	.name = "imx8-dc",
> >> +	.desc = "i.MX8 DC DRM graphics",
> >> +	.date = "20240530",
> >> +	.major = 1,
> >> +	.minor = 0,
> >> +	.patchlevel = 0,
> >> +};
> >> +
> >> +static void
> >> +dc_add_components(struct device *dev, struct component_match **matchptr)
> >> +{
> >> +	struct device_node *child, *grandchild;
> >> +
> >> +	for_each_available_child_of_node(dev->of_node, child) {
> >> +		/* The interrupt controller is not a component. */
> >> +		if (of_device_is_compatible(child, "fsl,imx8qxp-dc-intc"))
> >> +			continue;
> >> +
> >> +		drm_of_component_match_add(dev, matchptr, component_compare_of,
> >> +					   child);
> >> +
> >> +		for_each_available_child_of_node(child, grandchild)
> >> +			drm_of_component_match_add(dev, matchptr,
> >> +						   component_compare_of,
> >> +						   grandchild);
> >> +	}
> >> +}
> >> +
> >> +static void dc_drm_component_unbind_all(void *ptr)
> >> +{
> >> +	struct dc_drm_device *dc_drm = ptr;
> >> +	struct drm_device *drm = &dc_drm->base;
> >> +
> >> +	component_unbind_all(drm->dev, dc_drm);
> >> +}
> >> +
> >> +static int dc_drm_bind(struct device *dev)
> >> +{
> >> +	struct dc_priv *priv = dev_get_drvdata(dev);
> >> +	struct dc_drm_device *dc_drm;
> >> +	struct drm_device *drm;
> >> +	int ret;
> >> +
> >> +	dc_drm = devm_drm_dev_alloc(dev, &dc_drm_driver, struct dc_drm_device,
> >> +				    base);
> >> +	if (IS_ERR(dc_drm))
> >> +		return PTR_ERR(dc_drm);
> >> +
> >> +	drm = &dc_drm->base;
> >> +
> >> +	ret = component_bind_all(dev, dc_drm);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	ret = devm_add_action_or_reset(dev, dc_drm_component_unbind_all,
> >> +				       dc_drm);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	ret = dc_kms_init(dc_drm);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	ret = drm_dev_register(drm, 0);
> >> +	if (ret) {
> >> +		dev_err(dev, "failed to register drm device: %d\n", ret);
> >> +		goto err;
> >> +	}
> >> +
> >> +	drm_client_setup_with_fourcc(drm, DRM_FORMAT_XRGB8888);
> >> +
> >> +	priv->drm = drm;
> >> +
> >> +	return 0;
> >> +
> >> +err:
> >> +	dc_kms_uninit(dc_drm);
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +static void dc_drm_unbind(struct device *dev)
> >> +{
> >> +	struct dc_priv *priv = dev_get_drvdata(dev);
> >> +	struct dc_drm_device *dc_drm = to_dc_drm_device(priv->drm);
> >> +	struct drm_device *drm = &dc_drm->base;
> >> +	struct drm_crtc *crtc;
> >> +
> >> +	priv->drm = NULL;
> >> +	drm_dev_unplug(drm);
> >> +	dc_kms_uninit(dc_drm);
> >> +	drm_atomic_helper_shutdown(drm);
> >> +
> >> +	drm_for_each_crtc(crtc, drm)
> >> +		dc_crtc_disable_at_unbind(crtc);
> > 
> > There should be no need for that. drm_atomic_helper_shutdown() should
> > disable all the CRTCs.
> 
> In case DRM device is unplugged, drm_atomic_helper_shutdown does not
> effectively disable the CRTCs due to the bypassed logics wrapped by
> drm_dev_{enter,exit}.  That's why dc_crtc_disable_at_unbind() is called
> here to effectively disable the CRTCs.

I see. I haven't faced drm_dev_unplug() earlier. I checked, the "not
disabled" behaviour is documented and all other drivers don't perform
any kind of cleanup afterwards. Thus I think it's safe to drop the
dc_crtc_disable_at_unbind() unless it causes any kind of HW issues.

> 
> > 
> > Also, who is going to do drm_dev_unregister()? I don't see it in the
> > code.
> 
> drm_dev_unplug() right above calls drm_dev_unregister().
> 
> > 
> >> +}
> >> +
> >> +static const struct component_master_ops dc_drm_ops = {
> >> +	.bind = dc_drm_bind,
> >> +	.unbind = dc_drm_unbind,
> >> +};
> >> +
> >> +static int dc_probe(struct platform_device *pdev)
> >> +{
> >> +	struct component_match *match = NULL;
> >> +	struct dc_priv *priv;
> >> +	int ret;
> >> +
> >> +	priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
> >> +	if (!priv)
> >> +		return -ENOMEM;
> >> +
> >> +	priv->clk_cfg = devm_clk_get(&pdev->dev, NULL);
> >> +	if (IS_ERR(priv->clk_cfg))
> >> +		return dev_err_probe(&pdev->dev, PTR_ERR(priv->clk_cfg),
> >> +				     "failed to get cfg clock\n");
> >> +
> >> +	dev_set_drvdata(&pdev->dev, priv);
> >> +
> >> +	ret = dma_set_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(32));
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	ret = devm_pm_runtime_enable(&pdev->dev);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	ret = devm_of_platform_populate(&pdev->dev);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	dc_add_components(&pdev->dev, &match);
> >> +
> >> +	ret = component_master_add_with_match(&pdev->dev, &dc_drm_ops, match);
> >> +	if (ret)
> >> +		return dev_err_probe(&pdev->dev, ret,
> >> +				     "failed to add component master\n");
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static void dc_remove(struct platform_device *pdev)
> >> +{
> >> +	component_master_del(&pdev->dev, &dc_drm_ops);
> >> +}
> >> +
> >> +static int dc_runtime_suspend(struct device *dev)
> >> +{
> >> +	struct dc_priv *priv = dev_get_drvdata(dev);
> >> +
> >> +	clk_disable_unprepare(priv->clk_cfg);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int dc_runtime_resume(struct device *dev)
> >> +{
> >> +	struct dc_priv *priv = dev_get_drvdata(dev);
> >> +	int ret;
> >> +
> >> +	ret = clk_prepare_enable(priv->clk_cfg);
> >> +	if (ret)
> >> +		dev_err(dev, "failed to enable cfg clock: %d\n", ret);
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +static int dc_suspend(struct device *dev)
> >> +{
> >> +	struct dc_priv *priv = dev_get_drvdata(dev);
> >> +
> >> +	return drm_mode_config_helper_suspend(priv->drm);
> >> +}
> >> +
> >> +static int dc_resume(struct device *dev)
> >> +{
> >> +	struct dc_priv *priv = dev_get_drvdata(dev);
> >> +
> >> +	return drm_mode_config_helper_resume(priv->drm);
> >> +}
> >> +
> >> +static void dc_shutdown(struct platform_device *pdev)
> >> +{
> >> +	struct dc_priv *priv = dev_get_drvdata(&pdev->dev);
> >> +
> >> +	drm_atomic_helper_shutdown(priv->drm);
> >> +}
> >> +
> >> +static const struct dev_pm_ops dc_pm_ops = {
> >> +	RUNTIME_PM_OPS(dc_runtime_suspend, dc_runtime_resume, NULL)
> >> +	SYSTEM_SLEEP_PM_OPS(dc_suspend, dc_resume)
> >> +};
> >> +
> >> +static const struct of_device_id dc_dt_ids[] = {
> >> +	{ .compatible = "fsl,imx8qxp-dc", },
> >> +	{ /* sentinel */ }
> >> +};
> >> +MODULE_DEVICE_TABLE(of, dc_dt_ids);
> >> +
> >> +static struct platform_driver dc_driver = {
> >> +	.probe = dc_probe,
> >> +	.remove = dc_remove,
> >> +	.shutdown = dc_shutdown,
> >> +	.driver = {
> >> +		.name = "imx8-dc",
> >> +		.of_match_table	= dc_dt_ids,
> >> +		.pm = pm_sleep_ptr(&dc_pm_ops),
> >> +	},
> >> +};
> >> +
> >>  static struct platform_driver * const dc_drivers[] = {
> >>  	&dc_cf_driver,
> >>  	&dc_de_driver,
> >> @@ -19,6 +262,7 @@ static struct platform_driver * const dc_drivers[] = {
> >>  	&dc_lb_driver,
> >>  	&dc_pe_driver,
> >>  	&dc_tc_driver,
> >> +	&dc_driver,
> >>  };
> >>  
> >>  static int __init dc_drm_init(void)
> >> diff --git a/drivers/gpu/drm/imx/dc/dc-drv.h b/drivers/gpu/drm/imx/dc/dc-drv.h
> >> index 3b11f4862c6c..39a771a13933 100644
> >> --- a/drivers/gpu/drm/imx/dc/dc-drv.h
> >> +++ b/drivers/gpu/drm/imx/dc/dc-drv.h
> >> @@ -6,19 +6,38 @@
> >>  #ifndef __DC_DRV_H__
> >>  #define __DC_DRV_H__
> >>  
> >> +#include <linux/container_of.h>
> >>  #include <linux/platform_device.h>
> >>  
> >>  #include <drm/drm_device.h>
> >> +#include <drm/drm_encoder.h>
> >>  
> >>  #include "dc-de.h"
> >> +#include "dc-kms.h"
> >>  #include "dc-pe.h"
> >>  
> >>  struct dc_drm_device {
> >>  	struct drm_device base;
> >> +	struct dc_crtc dc_crtc[DC_DISPLAYS];
> >> +	struct dc_plane dc_primary[DC_DISPLAYS];
> >> +	struct drm_encoder encoder[DC_DISPLAYS];
> >>  	struct dc_de *de[DC_DISPLAYS];
> >>  	struct dc_pe *pe;
> >>  };
> >>  
> >> +static inline struct dc_drm_device *to_dc_drm_device(struct drm_device *drm)
> >> +{
> >> +	return container_of(drm, struct dc_drm_device, base);
> >> +}
> >> +
> >> +int dc_crtc_init(struct dc_drm_device *dc_drm, int crtc_index);
> >> +int dc_crtc_post_init(struct dc_drm_device *dc_drm, int crtc_index);
> >> +
> >> +int dc_kms_init(struct dc_drm_device *dc_drm);
> >> +void dc_kms_uninit(struct dc_drm_device *dc_drm);
> >> +
> >> +int dc_plane_init(struct dc_drm_device *dc_drm, struct dc_plane *dc_plane);
> >> +
> >>  extern struct platform_driver dc_cf_driver;
> >>  extern struct platform_driver dc_ed_driver;
> >>  extern struct platform_driver dc_de_driver;
> >> diff --git a/drivers/gpu/drm/imx/dc/dc-kms.c b/drivers/gpu/drm/imx/dc/dc-kms.c
> >> new file mode 100644
> >> index 000000000000..2b18aa37a4a8
> >> --- /dev/null
> >> +++ b/drivers/gpu/drm/imx/dc/dc-kms.c
> >> @@ -0,0 +1,143 @@
> >> +// SPDX-License-Identifier: GPL-2.0+
> >> +/*
> >> + * Copyright 2024 NXP
> >> + */
> >> +
> >> +#include <linux/of.h>
> >> +#include <linux/of_graph.h>
> >> +
> >> +#include <drm/drm_atomic_helper.h>
> >> +#include <drm/drm_bridge.h>
> >> +#include <drm/drm_bridge_connector.h>
> >> +#include <drm/drm_connector.h>
> >> +#include <drm/drm_crtc.h>
> >> +#include <drm/drm_device.h>
> >> +#include <drm/drm_encoder.h>
> >> +#include <drm/drm_gem_framebuffer_helper.h>
> >> +#include <drm/drm_mode_config.h>
> >> +#include <drm/drm_print.h>
> >> +#include <drm/drm_probe_helper.h>
> >> +#include <drm/drm_simple_kms_helper.h>
> >> +#include <drm/drm_vblank.h>
> >> +
> >> +#include "dc-de.h"
> >> +#include "dc-drv.h"
> >> +#include "dc-kms.h"
> >> +
> >> +static const struct drm_mode_config_funcs dc_drm_mode_config_funcs = {
> >> +	.fb_create = drm_gem_fb_create,
> >> +	.atomic_check = drm_atomic_helper_check,
> >> +	.atomic_commit = drm_atomic_helper_commit,
> >> +};
> >> +
> >> +static int dc_kms_init_encoder_per_crtc(struct dc_drm_device *dc_drm,
> >> +					int crtc_index)
> >> +{
> >> +	struct dc_crtc *dc_crtc = &dc_drm->dc_crtc[crtc_index];
> >> +	struct drm_device *drm = &dc_drm->base;
> >> +	struct drm_crtc *crtc = &dc_crtc->base;
> >> +	struct drm_connector *connector;
> >> +	struct device *dev = drm->dev;
> >> +	struct drm_encoder *encoder;
> >> +	struct drm_bridge *bridge;
> >> +	int ret;
> >> +
> >> +	bridge = devm_drm_of_get_bridge(dev, dc_crtc->de->tc->dev->of_node,
> >> +					0, 0);
> >> +	if (IS_ERR(bridge)) {
> >> +		ret = PTR_ERR(bridge);
> >> +		if (ret == -ENODEV)
> >> +			return 0;
> >> +
> >> +		return dev_err_probe(dev, ret,
> >> +				     "failed to find bridge for CRTC%u\n",
> >> +				     crtc->index);
> >> +	}
> >> +
> >> +	encoder = &dc_drm->encoder[crtc_index];
> >> +	ret = drm_simple_encoder_init(drm, encoder, DRM_MODE_ENCODER_NONE);
> >> +	if (ret) {
> >> +		dev_err(dev, "failed to initialize encoder for CRTC%u: %d\n",
> >> +			crtc->index, ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	encoder->possible_crtcs = drm_crtc_mask(crtc);
> >> +
> >> +	ret = drm_bridge_attach(encoder, bridge, NULL,
> >> +				DRM_BRIDGE_ATTACH_NO_CONNECTOR);
> >> +	if (ret) {
> >> +		dev_err(dev,
> >> +			"failed to attach bridge to encoder for CRTC%u: %d\n",
> >> +			crtc->index, ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	connector = drm_bridge_connector_init(drm, encoder);
> >> +	if (IS_ERR(connector)) {
> >> +		ret = PTR_ERR(connector);
> >> +		dev_err(dev, "failed to init bridge connector for CRTC%u: %d\n",
> >> +			crtc->index, ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	ret = drm_connector_attach_encoder(connector, encoder);
> >> +	if (ret)
> >> +		dev_err(dev,
> >> +			"failed to attach encoder to connector for CRTC%u: %d\n",
> >> +			crtc->index, ret);
> >> +
> >> +	return ret;
> >> +}
> >> +
> >> +int dc_kms_init(struct dc_drm_device *dc_drm)
> >> +{
> >> +	struct drm_device *drm = &dc_drm->base;
> >> +	int ret, i;
> >> +
> >> +	ret = drmm_mode_config_init(drm);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	drm->mode_config.min_width = 60;
> >> +	drm->mode_config.min_height = 60;
> >> +	drm->mode_config.max_width = 8192;
> >> +	drm->mode_config.max_height = 8192;
> >> +	drm->mode_config.funcs = &dc_drm_mode_config_funcs;
> >> +
> >> +	drm->vblank_disable_immediate = true;
> >> +	drm->max_vblank_count = DC_FRAMEGEN_MAX_FRAME_INDEX;
> >> +
> >> +	for (i = 0; i < DC_DISPLAYS; i++) {
> >> +		ret = dc_crtc_init(dc_drm, i);
> >> +		if (ret)
> >> +			return ret;
> >> +
> >> +		ret = dc_kms_init_encoder_per_crtc(dc_drm, i);
> >> +		if (ret)
> >> +			return ret;
> >> +	}
> >> +
> >> +	for (i = 0; i < DC_DISPLAYS; i++) {
> >> +		ret = dc_crtc_post_init(dc_drm, i);
> > 
> > Can you use .late_register for this?
> 
> Kerneldoc of struct drm_crtc_funcs::late_register says it's used to register
> additional userspace interfaces like debugfs interfaces. And, it seems that
> everyone implementing this uses it to add debugfs interfaces. So, it will
> kind of abuse it to do CRTC post initialization.

Why can't they be requested earlier then?

> 
> > 
> >> +		if (ret)
> >> +			return ret;
> >> +	}
> >> +
> >> +	ret = drm_vblank_init(drm, DC_DISPLAYS);
> >> +	if (ret) {
> >> +		dev_err(drm->dev, "failed to init vblank support: %d\n", ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	drm_mode_config_reset(drm);
> >> +
> >> +	drm_kms_helper_poll_init(drm);
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +void dc_kms_uninit(struct dc_drm_device *dc_drm)
> >> +{
> >> +	drm_kms_helper_poll_fini(&dc_drm->base);
> >> +}
> >> diff --git a/drivers/gpu/drm/imx/dc/dc-kms.h b/drivers/gpu/drm/imx/dc/dc-kms.h
> >> new file mode 100644
> >> index 000000000000..57f6e0c15f57
> >> --- /dev/null
> >> +++ b/drivers/gpu/drm/imx/dc/dc-kms.h
> >> @@ -0,0 +1,58 @@
> >> +/* SPDX-License-Identifier: GPL-2.0+ */
> >> +/*
> >> + * Copyright 2024 NXP
> >> + */
> >> +
> >> +#ifndef __DC_KMS_H__
> >> +#define __DC_KMS_H__
> >> +
> >> +#include <linux/completion.h>
> >> +
> >> +#include <drm/drm_crtc.h>
> >> +#include <drm/drm_plane.h>
> >> +#include <drm/drm_vblank.h>
> >> +
> >> +#include "dc-de.h"
> >> +#include "dc-fu.h"
> >> +#include "dc-pe.h"
> >> +
> >> +#define DC_CRTC_IRQS	5
> >> +
> >> +struct dc_crtc_irq {
> >> +	struct dc_crtc *dc_crtc;
> >> +	unsigned int irq;
> >> +};
> >> +
> > 
> > Please provide some documentation for the structure in the form of the
> > kerneldoc. E.g. what is the difference between ed_cont and ed_safe?
> 
> Will add kerneldoc for struct dc_{crtc,plane,drm_device} and tell the
> difference between ed_cont(content stream) and ed_safe(safety stream).
> 
> > The de and fg pointers are global, please don't cache them
> > unnecessarily.
> 
> Global? I don't catch your meaning, sorry. To me, it's handy to access de
> and fg via the two pointers in struct dc_crtc.

I had to spend some time understanding if they are per-CRTC or if there
are a single instances of those subdevices. Thus I suggest to access
them through dc_drm_device. You can ignore this suggestion though.

> 
> > 
> >> +struct dc_crtc {
> >> +	struct drm_crtc base;
> >> +	struct dc_de *de;
> >> +	struct dc_pe *pe;
> >> +	struct dc_cf *cf_cont;
> >> +	struct dc_cf *cf_safe;
> >> +	struct dc_ed *ed_cont;
> >> +	struct dc_ed *ed_safe;
> >> +	struct dc_fg *fg;
> >> +	unsigned int irq_dec_framecomplete;
> >> +	unsigned int irq_dec_seqcomplete;
> >> +	unsigned int irq_dec_shdld;
> >> +	unsigned int irq_ed_cont_shdld;
> >> +	unsigned int irq_ed_safe_shdld;
> >> +	struct completion dec_seqcomplete_done;
> >> +	struct completion dec_shdld_done;
> >> +	struct completion ed_safe_shdld_done;
> >> +	struct completion ed_cont_shdld_done;
> >> +	struct drm_pending_vblank_event *event;
> >> +	struct dc_crtc_irq irqs[DC_CRTC_IRQS];
> >> +};
> >> +
> >> +struct dc_plane {
> >> +	struct drm_plane base;
> >> +	struct dc_fu *fu;
> >> +	struct dc_cf *cf;
> >> +	struct dc_lb *lb;
> >> +	struct dc_ed *ed;
> >> +};
> >> +
> >> +void dc_crtc_disable_at_unbind(struct drm_crtc *crtc);
> >> +
> >> +#endif /* __DC_KMS_H__ */
> >> diff --git a/drivers/gpu/drm/imx/dc/dc-plane.c b/drivers/gpu/drm/imx/dc/dc-plane.c
> >> new file mode 100644
> >> index 000000000000..78d0d2cd3451
> >> --- /dev/null
> >> +++ b/drivers/gpu/drm/imx/dc/dc-plane.c
> >> @@ -0,0 +1,241 @@
> >> +// SPDX-License-Identifier: GPL-2.0+
> >> +/*
> >> + * Copyright 2024 NXP
> >> + */
> >> +
> >> +#include <linux/container_of.h>
> >> +
> >> +#include <drm/drm_atomic.h>
> >> +#include <drm/drm_atomic_helper.h>
> >> +#include <drm/drm_atomic_state_helper.h>
> >> +#include <drm/drm_crtc.h>
> >> +#include <drm/drm_drv.h>
> >> +#include <drm/drm_fb_dma_helper.h>
> >> +#include <drm/drm_fourcc.h>
> >> +#include <drm/drm_framebuffer.h>
> >> +#include <drm/drm_gem_atomic_helper.h>
> >> +#include <drm/drm_plane_helper.h>
> >> +#include <drm/drm_print.h>
> >> +
> >> +#include "dc-drv.h"
> >> +#include "dc-fu.h"
> >> +#include "dc-kms.h"
> >> +
> >> +#define DC_PLANE_MAX_PITCH	0x10000
> >> +#define DC_PLANE_MAX_PIX_CNT	8192
> >> +
> >> +#define dc_plane_dbg(plane, fmt, ...)					\
> >> +do {									\
> >> +	typeof(plane) _plane = (plane);					\
> >> +	drm_dbg_kms(_plane->dev, "[PLANE:%d:%s] " fmt,			\
> >> +		    _plane->base.id, _plane->name, ##__VA_ARGS__);	\
> >> +} while (0)
> >> +
> >> +static const uint32_t dc_plane_formats[] = {
> >> +	DRM_FORMAT_XRGB8888,
> >> +};
> >> +
> >> +static const struct drm_plane_funcs dc_plane_funcs = {
> >> +	.update_plane		= drm_atomic_helper_update_plane,
> >> +	.disable_plane		= drm_atomic_helper_disable_plane,
> >> +	.destroy		= drm_plane_cleanup,
> >> +	.reset			= drm_atomic_helper_plane_reset,
> >> +	.atomic_duplicate_state	= drm_atomic_helper_plane_duplicate_state,
> >> +	.atomic_destroy_state	= drm_atomic_helper_plane_destroy_state,
> >> +};
> >> +
> >> +static inline struct dc_plane *to_dc_plane(struct drm_plane *plane)
> >> +{
> >> +	return container_of(plane, struct dc_plane, base);
> >> +}
> >> +
> >> +static int dc_plane_check_no_off_screen(struct drm_plane_state *state,
> >> +					struct drm_crtc_state *crtc_state)
> >> +{
> >> +	if (state->dst.x1 < 0 || state->dst.y1 < 0 ||
> >> +	    state->dst.x2 > crtc_state->adjusted_mode.hdisplay ||
> >> +	    state->dst.y2 > crtc_state->adjusted_mode.vdisplay) {
> >> +		dc_plane_dbg(state->plane, "no off screen\n");
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int dc_plane_check_max_source_resolution(struct drm_plane_state *state)
> >> +{
> >> +	int src_h = drm_rect_height(&state->src) >> 16;
> >> +	int src_w = drm_rect_width(&state->src) >> 16;
> >> +
> >> +	if (src_w > DC_PLANE_MAX_PIX_CNT || src_h > DC_PLANE_MAX_PIX_CNT) {
> >> +		dc_plane_dbg(state->plane, "invalid source resolution\n");
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int dc_plane_check_fb(struct drm_plane_state *state)
> >> +{
> >> +	struct drm_framebuffer *fb = state->fb;
> >> +	dma_addr_t baseaddr = drm_fb_dma_get_gem_addr(fb, state, 0);
> >> +
> >> +	/* base address alignment */
> >> +	if (baseaddr & 0x3) {
> >> +		dc_plane_dbg(state->plane, "fb bad baddr alignment\n");
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	/* pitches[0] range */
> >> +	if (fb->pitches[0] > DC_PLANE_MAX_PITCH) {
> >> +		dc_plane_dbg(state->plane, "fb pitches[0] is out of range\n");
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	/* pitches[0] alignment */
> >> +	if (fb->pitches[0] & 0x3) {
> >> +		dc_plane_dbg(state->plane, "fb bad pitches[0] alignment\n");
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	return 0;
> >> +}
> >> +
> >> +static int
> >> +dc_plane_atomic_check(struct drm_plane *plane, struct drm_atomic_state *state)
> >> +{
> >> +	struct drm_plane_state *plane_state =
> >> +				drm_atomic_get_new_plane_state(state, plane);
> >> +	struct drm_crtc_state *crtc_state;
> >> +	int ret;
> >> +
> >> +	/* ok to disable */
> >> +	if (!plane_state->fb)
> >> +		return 0;
> >> +
> >> +	if (!plane_state->crtc) {
> >> +		dc_plane_dbg(plane, "no CRTC in plane state\n");
> >> +		return -EINVAL;
> >> +	}
> >> +
> >> +	crtc_state =
> >> +		drm_atomic_get_existing_crtc_state(state, plane_state->crtc);
> >> +	if (WARN_ON(!crtc_state))
> >> +		return -EINVAL;
> >> +
> >> +	ret = drm_atomic_helper_check_plane_state(plane_state, crtc_state,
> >> +						  DRM_PLANE_NO_SCALING,
> >> +						  DRM_PLANE_NO_SCALING,
> >> +						  true, false);
> >> +	if (ret) {
> >> +		dc_plane_dbg(plane, "failed to check plane state: %d\n", ret);
> >> +		return ret;
> >> +	}
> >> +
> >> +	ret = dc_plane_check_no_off_screen(plane_state, crtc_state);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	ret = dc_plane_check_max_source_resolution(plane_state);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	return dc_plane_check_fb(plane_state);
> >> +}
> >> +
> >> +static void
> >> +dc_plane_atomic_update(struct drm_plane *plane, struct drm_atomic_state *state)
> >> +{
> >> +	struct drm_plane_state *new_state =
> >> +				drm_atomic_get_new_plane_state(state, plane);
> >> +	struct dc_plane *dplane = to_dc_plane(plane);
> >> +	struct drm_framebuffer *fb = new_state->fb;
> >> +	const struct dc_fu_ops *fu_ops;
> >> +	struct dc_lb *lb = dplane->lb;
> >> +	struct dc_fu *fu = dplane->fu;
> >> +	dma_addr_t baseaddr;
> >> +	int src_w, src_h;
> >> +	int idx;
> >> +
> >> +	if (!drm_dev_enter(plane->dev, &idx))
> >> +		return;
> >> +
> >> +	src_w = drm_rect_width(&new_state->src) >> 16;
> >> +	src_h = drm_rect_height(&new_state->src) >> 16;
> >> +
> >> +	baseaddr = drm_fb_dma_get_gem_addr(fb, new_state, 0);
> >> +
> >> +	fu_ops = dc_fu_get_ops(dplane->fu);
> >> +
> >> +	fu_ops->set_layerblend(fu, lb);
> >> +	fu_ops->set_burstlength(fu, baseaddr);
> >> +	fu_ops->set_src_stride(fu, DC_FETCHUNIT_FRAC0, fb->pitches[0]);
> >> +	fu_ops->set_src_buf_dimensions(fu, DC_FETCHUNIT_FRAC0, src_w, src_h);
> >> +	fu_ops->set_fmt(fu, DC_FETCHUNIT_FRAC0, fb->format);
> >> +	fu_ops->set_framedimensions(fu, src_w, src_h);
> >> +	fu_ops->set_baseaddress(fu, DC_FETCHUNIT_FRAC0, baseaddr);
> >> +	fu_ops->enable_src_buf(fu, DC_FETCHUNIT_FRAC0);
> >> +
> >> +	dc_plane_dbg(plane, "uses %s\n", fu_ops->get_name(fu));
> >> +
> >> +	dc_lb_pec_dynamic_prim_sel(lb, dc_cf_get_link_id(dplane->cf));
> >> +	dc_lb_pec_dynamic_sec_sel(lb, fu_ops->get_link_id(fu));
> >> +	dc_lb_mode(lb, LB_BLEND);
> >> +	dc_lb_position(lb, new_state->dst.x1, new_state->dst.y1);
> >> +	dc_lb_pec_clken(lb, CLKEN_AUTOMATIC);
> >> +
> >> +	dc_plane_dbg(plane, "uses LayerBlend%u\n", dc_lb_get_id(lb));
> >> +
> >> +	/* set ExtDst's source to LayerBlend */
> >> +	dc_ed_pec_src_sel(dplane->ed, dc_lb_get_link_id(lb));
> >> +
> >> +	drm_dev_exit(idx);
> >> +}
> >> +
> >> +static void dc_plane_atomic_disable(struct drm_plane *plane,
> >> +				    struct drm_atomic_state *state)
> >> +{
> >> +	struct dc_plane *dplane = to_dc_plane(plane);
> >> +	const struct dc_fu_ops *fu_ops;
> >> +	int idx;
> >> +
> >> +	if (!drm_dev_enter(plane->dev, &idx))
> >> +		return;
> >> +
> >> +	/* disable fetchunit in shadow */
> >> +	fu_ops = dc_fu_get_ops(dplane->fu);
> >> +	fu_ops->disable_src_buf(dplane->fu, DC_FETCHUNIT_FRAC0);
> >> +
> >> +	/* set ExtDst's source to ConstFrame */
> >> +	dc_ed_pec_src_sel(dplane->ed, dc_cf_get_link_id(dplane->cf));
> >> +
> >> +	drm_dev_exit(idx);
> >> +}
> >> +
> >> +static const struct drm_plane_helper_funcs dc_plane_helper_funcs = {
> >> +	.atomic_check = dc_plane_atomic_check,
> >> +	.atomic_update = dc_plane_atomic_update,
> >> +	.atomic_disable = dc_plane_atomic_disable,
> >> +};
> >> +
> >> +int dc_plane_init(struct dc_drm_device *dc_drm, struct dc_plane *dc_plane)
> >> +{
> >> +	struct drm_plane *plane = &dc_plane->base;
> >> +	int ret;
> >> +
> >> +	ret = drm_universal_plane_init(&dc_drm->base, plane, 0, &dc_plane_funcs,
> >> +				       dc_plane_formats,
> >> +				       ARRAY_SIZE(dc_plane_formats),
> >> +				       NULL, DRM_PLANE_TYPE_PRIMARY, NULL);
> >> +	if (ret)
> >> +		return ret;
> >> +
> >> +	drm_plane_helper_add(plane, &dc_plane_helper_funcs);
> >> +
> >> +	dc_plane->fu = dc_drm->pe->fu_disp[plane->index];
> >> +	dc_plane->cf = dc_drm->pe->cf_cont[plane->index];
> >> +	dc_plane->lb = dc_drm->pe->lb[plane->index];
> >> +	dc_plane->ed = dc_drm->pe->ed_cont[plane->index];
> >> +
> >> +	return 0;
> >> +}
> >> -- 
> >> 2.34.1
> >>
> > 
> 
> -- 
> Regards,
> Liu Ying

-- 
With best wishes
Dmitry



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