Re: [PATCH v2 5/5] drm/ingenic: Add option to alloc cached GEM buffers

Paul Cercueil
2021-03-10T19:02:08Z

Hi Hillf,

Le lun. 8 mars 2021 à 11:47, Hillf Danton <hdanton@sina.com> a écrit :
> On Sun, 7 Mar 2021 20:28:35 +0000 Paul Cercueil wrote:
>> With the module parameter ingenic-drm.cached_gem_buffers, it is
>> possible
>> to specify that we want GEM buffers backed by non-coherent memory.
>>
>> This dramatically speeds up software rendering on Ingenic SoCs,
>> even for
>> tasks where write-combine memory should in theory be faster (e.g.
>> simple
>> blits).
>
> Wondering if it is due to the tricks at [1].
>
> If so, is dma_alloc_noncoherent() necessary in this patchset?

You confuse non-contiguous with non-coherent, which are two different
things.

Cheers,
-Paul

> Christoph can you give us a concise lesson on noncoherency covering
> at least
> noncoherent device, noncoherent memory(used in this work), no coherent
> caching(in [1]), their links to speedup, and the thumb rule to handle
> noncoherency in workdays. It feels toe curling every time I see
> noncoherence
> going downtown with speedup hand in hand.
>
> [1] Subject: [PATCH 6/6] media: uvcvideo: Use dma_alloc_noncontiguos
> API
> https://lore.kernel.org/lkml/20210301085236.947011-7-hch@lst.de/#t
>
>>
>> Leave it disabled by default, since it is specific to one use-case
>> (software rendering).
>>
>> v2: Rework code to work with new DRM APIs regarding plane states
>>
>> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
>> ---
>> drivers/gpu/drm/ingenic/ingenic-drm-drv.c | 49
>> ++++++++++++++++++++++-
>> drivers/gpu/drm/ingenic/ingenic-drm.h | 4 ++
>> drivers/gpu/drm/ingenic/ingenic-ipu.c | 14 ++++++-
>> 3 files changed, 63 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
>> b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
>> index d60e1eefc9d1..ba1ac0fcda74 100644
>> --- a/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
>> +++ b/drivers/gpu/drm/ingenic/ingenic-drm-drv.c
>> @@ -9,6 +9,7 @@
>> #include <linux/component.h>
>> #include <linux/clk.h>
>> #include <linux/dma-mapping.h>
>> +#include <linux/io.h>
>> #include <linux/module.h>
>> #include <linux/mutex.h>
>> #include <linux/of_device.h>
>> @@ -23,6 +24,7 @@
>> #include <drm/drm_color_mgmt.h>
>> #include <drm/drm_crtc.h>
>> #include <drm/drm_crtc_helper.h>
>> +#include <drm/drm_damage_helper.h>
>> #include <drm/drm_drv.h>
>> #include <drm/drm_gem_cma_helper.h>
>> #include <drm/drm_fb_cma_helper.h>
>> @@ -99,6 +101,11 @@ struct ingenic_drm {
>> struct notifier_block clock_nb;
>> };
>>
>> +static bool ingenic_drm_cached_gem_buf;
>> +module_param_named(cached_gem_buffers, ingenic_drm_cached_gem_buf,
>> bool, 0400);
>> +MODULE_PARM_DESC(cached_gem_buffers,
>> + "Enable fully cached GEM buffers [default=false]");
>> +
>> static bool ingenic_drm_writeable_reg(struct device *dev, unsigned
>> int reg)
>> {
>> switch (reg) {
>> @@ -410,6 +417,8 @@ static int
>> ingenic_drm_plane_atomic_check(struct drm_plane *plane,
>> old_plane_state->fb->format->format !=
>> new_plane_state->fb->format->format))
>> crtc_state->mode_changed = true;
>>
>> + drm_atomic_helper_check_plane_damage(state, new_plane_state);
>> +
>> return 0;
>> }
>>
>> @@ -541,10 +550,20 @@ static void ingenic_drm_update_palette(struct
>> ingenic_drm *priv,
>> }
>> }
>>
>> +void ingenic_drm_sync_data(struct device *dev,
>> + struct drm_plane_state *old_state,
>> + struct drm_plane_state *state)
>> +{
>> + if (ingenic_drm_cached_gem_buf)
>> + drm_gem_cma_sync_data(dev, old_state, state);
>> +}
>> +
>> static void ingenic_drm_plane_atomic_update(struct drm_plane
>> *plane,
>> struct drm_atomic_state *state)
>> {
>> struct ingenic_drm *priv = drm_device_get_priv(plane->dev);
>> + struct drm_plane_state *oldstate =
>> drm_atomic_get_old_plane_state(state,
>> + plane);
>> struct drm_plane_state *newstate =
>> drm_atomic_get_new_plane_state(state,
>> plane);
>> struct drm_crtc_state *crtc_state;
>> @@ -554,6 +573,8 @@ static void
>> ingenic_drm_plane_atomic_update(struct drm_plane *plane,
>> u32 fourcc;
>>
>> if (newstate && newstate->fb) {
>> + ingenic_drm_sync_data(priv->dev, oldstate, newstate);
>> +
>> crtc_state = newstate->crtc->state;
>>
>> addr = drm_fb_cma_get_gem_addr(newstate->fb, newstate, 0);
>> @@ -743,6 +764,26 @@ static void ingenic_drm_disable_vblank(struct
>> drm_crtc *crtc)
>> regmap_update_bits(priv->map, JZ_REG_LCD_CTRL,
>> JZ_LCD_CTRL_EOF_IRQ, 0);
>> }
>>
>> +static struct drm_framebuffer *
>> +ingenic_drm_gem_fb_create(struct drm_device *dev, struct drm_file
>> *file,
>> + const struct drm_mode_fb_cmd2 *mode_cmd)
>> +{
>> + if (ingenic_drm_cached_gem_buf)
>> + return drm_gem_fb_create_with_dirty(dev, file, mode_cmd);
>> +
>> + return drm_gem_fb_create(dev, file, mode_cmd);
>> +}
>> +
>> +static int ingenic_drm_gem_cma_dumb_create(struct drm_file
>> *file_priv,
>> + struct drm_device *drm,
>> + struct drm_mode_create_dumb *args)
>> +{
>> + if (ingenic_drm_cached_gem_buf)
>> + return drm_gem_cma_dumb_create_noncoherent(file_priv, drm, args);
>> +
>> + return drm_gem_cma_dumb_create(file_priv, drm, args);
>> +}
>> +
>> DEFINE_DRM_GEM_CMA_FOPS(ingenic_drm_fops);
>>
>> static const struct drm_driver ingenic_drm_driver_data = {
>> @@ -755,7 +796,7 @@ static const struct drm_driver
>> ingenic_drm_driver_data = {
>> .patchlevel = 0,
>>
>> .fops = &ingenic_drm_fops,
>> - DRM_GEM_CMA_DRIVER_OPS,
>>
>> + DRM_GEM_CMA_DRIVER_OPS_WITH_DUMB_CREATE(ingenic_drm_gem_cma_dumb_create),
>>
>> .irq_handler = ingenic_drm_irq_handler,
>> };
>> @@ -805,7 +846,7 @@ static const struct drm_encoder_helper_funcs
>> ingenic_drm_encoder_helper_funcs =
>> };
>>
>> static const struct drm_mode_config_funcs
>> ingenic_drm_mode_config_funcs = {
>> - .fb_create = drm_gem_fb_create,
>> + .fb_create = ingenic_drm_gem_fb_create,
>> .output_poll_changed = drm_fb_helper_output_poll_changed,
>> .atomic_check = drm_atomic_helper_check,
>> .atomic_commit = drm_atomic_helper_commit,
>> @@ -962,6 +1003,8 @@ static int ingenic_drm_bind(struct device
>> *dev, bool has_components)
>> return ret;
>> }
>>
>> + drm_plane_enable_fb_damage_clips(&priv->f1);
>> +
>> drm_crtc_helper_add(&priv->crtc, &ingenic_drm_crtc_helper_funcs);
>>
>> ret = drm_crtc_init_with_planes(drm, &priv->crtc, primary,
>> @@ -990,6 +1033,8 @@ static int ingenic_drm_bind(struct device
>> *dev, bool has_components)
>> return ret;
>> }
>>
>> + drm_plane_enable_fb_damage_clips(&priv->f0);
>> +
>> if (IS_ENABLED(CONFIG_DRM_INGENIC_IPU) && has_components) {
>> ret = component_bind_all(dev, drm);
>> if (ret) {
>> diff --git a/drivers/gpu/drm/ingenic/ingenic-drm.h
>> b/drivers/gpu/drm/ingenic/ingenic-drm.h
>> index 1b4347f7f084..b6bca356e024 100644
>> --- a/drivers/gpu/drm/ingenic/ingenic-drm.h
>> +++ b/drivers/gpu/drm/ingenic/ingenic-drm.h
>> @@ -185,6 +185,10 @@ void ingenic_drm_plane_config(struct device
>> *dev,
>> struct drm_plane *plane, u32 fourcc);
>> void ingenic_drm_plane_disable(struct device *dev, struct
>> drm_plane *plane);
>>
>> +void ingenic_drm_sync_data(struct device *dev,
>> + struct drm_plane_state *old_state,
>> + struct drm_plane_state *state);
>> +
>> extern struct platform_driver *ingenic_ipu_driver_ptr;
>>
>> #endif /* DRIVERS_GPU_DRM_INGENIC_INGENIC_DRM_H */
>> diff --git a/drivers/gpu/drm/ingenic/ingenic-ipu.c
>> b/drivers/gpu/drm/ingenic/ingenic-ipu.c
>> index 5ae6adab8306..7826eab044ba 100644
>> --- a/drivers/gpu/drm/ingenic/ingenic-ipu.c
>> +++ b/drivers/gpu/drm/ingenic/ingenic-ipu.c
>> @@ -20,6 +20,7 @@
>>
>> #include <drm/drm_atomic.h>
>> #include <drm/drm_atomic_helper.h>
>> +#include <drm/drm_damage_helper.h>
>> #include <drm/drm_drv.h>
>> #include <drm/drm_fb_cma_helper.h>
>> #include <drm/drm_fourcc.h>
>> @@ -285,6 +286,8 @@ static void
>> ingenic_ipu_plane_atomic_update(struct drm_plane *plane,
>> struct drm_atomic_state *state)
>> {
>> struct ingenic_ipu *ipu = plane_to_ingenic_ipu(plane);
>> + struct drm_plane_state *oldstate =
>> drm_atomic_get_old_plane_state(state,
>> + plane);
>> struct drm_plane_state *newstate =
>> drm_atomic_get_new_plane_state(state,
>> plane);
>> const struct drm_format_info *finfo;
>> @@ -317,6 +320,8 @@ static void
>> ingenic_ipu_plane_atomic_update(struct drm_plane *plane,
>> JZ_IPU_CTRL_CHIP_EN | JZ_IPU_CTRL_LCDC_SEL);
>> }
>>
>> + ingenic_drm_sync_data(ipu->master, oldstate, newstate);
>> +
>> /* New addresses will be committed in vblank handler... */
>> ipu->addr_y = drm_fb_cma_get_gem_addr(newstate->fb, newstate, 0);
>> if (finfo->num_planes > 1)
>> @@ -541,7 +546,7 @@ static int
>> ingenic_ipu_plane_atomic_check(struct drm_plane *plane,
>>
>> if (!new_plane_state->crtc ||
>> !crtc_state->mode.hdisplay || !crtc_state->mode.vdisplay)
>> - return 0;
>> + goto out_check_damage;
>>
>> /* Plane must be fully visible */
>> if (new_plane_state->crtc_x < 0 || new_plane_state->crtc_y < 0 ||
>> @@ -558,7 +563,7 @@ static int
>> ingenic_ipu_plane_atomic_check(struct drm_plane *plane,
>> return -EINVAL;
>>
>> if (!osd_changed(new_plane_state, old_plane_state))
>> - return 0;
>> + goto out_check_damage;
>>
>> crtc_state->mode_changed = true;
>>
>> @@ -592,6 +597,9 @@ static int
>> ingenic_ipu_plane_atomic_check(struct drm_plane *plane,
>> ipu->denom_w = denom_w;
>> ipu->denom_h = denom_h;
>>
>> +out_check_damage:
>> + drm_atomic_helper_check_plane_damage(state, new_plane_state);
>> +
>> return 0;
>> }
>>
>> @@ -773,6 +781,8 @@ static int ingenic_ipu_bind(struct device *dev,
>> struct device *master, void *d)
>> return err;
>> }
>>
>> + drm_plane_enable_fb_damage_clips(plane);
>> +
>> /*
>> * Sharpness settings range is [0,32]
>> * 0 : nearest-neighbor
>> --
>> 2.30.1
>
>