From: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
To: Dan Scally <dan.scally@ideasonboard.com>
Cc: "Jacopo Mondi" <jacopo.mondi@ideasonboard.com>,
"Anthony McGivern" <anthony.mcgivern@arm.com>,
"Vincenzo Frascino" <vincenzo.frascino@arm.com>,
"Nayden Kanchev" <Nayden.Kanchev@arm.com>,
"Konstantin Babin" <Konstantin.Babin@arm.com>,
"Barnabás Pőcze" <barnabas.pocze@ideasonboard.com>,
"Mauro Carvalho Chehab" <mchehab@kernel.org>,
linux-media@vger.kernel.org, linux-kernel@vger.kernel.org,
stable@vger.kernel.org
Subject: Re: [PATCH v2 2/6] media: mali-c55: Initialize the ISP in enable_streams()
Date: Fri, 13 Mar 2026 18:00:50 +0100 [thread overview]
Message-ID: <abRBtB7e2Yc2XwBb@zed> (raw)
In-Reply-To: <5c0f9a45-4726-4d42-b209-9d80108147ae@ideasonboard.com>
Hi Dan
On Fri, Mar 13, 2026 at 04:14:09PM +0000, Dan Scally wrote:
> Hi Jacopo
>
> On 13/03/2026 16:10, Jacopo Mondi wrote:
> > Hi Dan
> >
> > On Fri, Mar 13, 2026 at 03:59:22PM +0000, Dan Scally wrote:
> > > Hi Jacopo - thanks for the patches
> > >
> > > On 13/03/2026 14:53, Jacopo Mondi wrote:
> > > > The Mali C55 driver initializes the ISP in two points:
> > > >
> > > > 1) At probe time it disables ISP blocks by configuring them in bypass
> > > > mode
> > > > 2) At enable_streams() it initializes the crop rectangles and the image
> > > > processing pipeline using the current image format
> > > >
> > > > However, as ISP blocks are configured by userspace, if their
> > > > configuration is not reset, from the second enable_streams() call
> > > > onwards the ISP configuration will depend on the previous streaming
> > > > session configuration.
> > > >
> > > > To re-initialize the ISP completely at enable_strems() time consolidate
> > >
> > > s/enable_strems/enable_streams
> > >
> > > > the ISP block bypass configuration and the image processing path
> > > > configuration in a single function to be called at enabled_streams()
> > > > time.
> > >
> > > I'm slightly confused; the change seems fine, but as far as I can see it's
> > > non-functional...or is this just preliminary reorganisation to make the next
> > > patch easier?
> >
> > Isn't mali_c55_init_context() only called at probe() time ?
> >
> > IOW all the bypass configuration that were only performed at probe
> > time are now performed at every streaming start.
> >
> > Or have I missed something ?
>
> But they're context rather than hardware writes; they're stored in the
> context's registers buffer and should persist past power off / on and then
> be re-written to the hardware when mali_c55_config_write() is called in
> mali_c55_isp_start() the next time streaming started...at least that's
> what's supposed to happen.
I'm not so concerned about power on/off but rather about configs from a
streaming session being applied to the following one.
In the case of the bypasses that are configured in
mali_c55_init_context(), at the moment there is no uAPI to enable
them.
However, rather soon we'll introduce blocks in the uAPI to enable
them, and I think there still is value in resetting the ISP
configuration in full at start streaming time. Do you agree ?
>
> Thanks
> Dan
>
> >
> > Thanks
> > j
> >
> > >
> > > Thanks
> > > Dan
> > >
> > > > Cc: stable@vger.kernel.org
> > > > Fixes: d5f281f3dd29 ("media: mali-c55: Add Mali-C55 ISP driver")
> > > > Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
> > > > ---
> > > > .../media/platform/arm/mali-c55/mali-c55-common.h | 2 +
> > > > .../media/platform/arm/mali-c55/mali-c55-core.c | 35 -----------
> > > > drivers/media/platform/arm/mali-c55/mali-c55-isp.c | 37 ++---------
> > > > .../media/platform/arm/mali-c55/mali-c55-params.c | 72 ++++++++++++++++++++++
> > > > 4 files changed, 79 insertions(+), 67 deletions(-)
> > > >
> > > > diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-common.h b/drivers/media/platform/arm/mali-c55/mali-c55-common.h
> > > > index 31c1deaca146..13a3e9dc4243 100644
> > > > --- a/drivers/media/platform/arm/mali-c55/mali-c55-common.h
> > > > +++ b/drivers/media/platform/arm/mali-c55/mali-c55-common.h
> > > > @@ -306,5 +306,7 @@ bool mali_c55_pipeline_ready(struct mali_c55 *mali_c55);
> > > > void mali_c55_stats_fill_buffer(struct mali_c55 *mali_c55,
> > > > enum mali_c55_config_spaces cfg_space);
> > > > void mali_c55_params_write_config(struct mali_c55 *mali_c55);
> > > > +void mali_c55_params_init_isp_config(struct mali_c55 *mali_c55,
> > > > + const struct v4l2_subdev_state *state);
> > > > #endif /* _MALI_C55_COMMON_H */
> > > > diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-core.c b/drivers/media/platform/arm/mali-c55/mali-c55-core.c
> > > > index 43b834459ccf..c1a562cd214e 100644
> > > > --- a/drivers/media/platform/arm/mali-c55/mali-c55-core.c
> > > > +++ b/drivers/media/platform/arm/mali-c55/mali-c55-core.c
> > > > @@ -663,41 +663,6 @@ static int mali_c55_init_context(struct mali_c55 *mali_c55,
> > > > mali_c55->base + config_space_addrs[MALI_C55_CONFIG_PING],
> > > > MALI_C55_CONFIG_SPACE_SIZE);
> > > > - /*
> > > > - * Some features of the ISP need to be disabled by default and only
> > > > - * enabled at the same time as they're configured by a parameters buffer
> > > > - */
> > > > -
> > > > - /* Bypass the sqrt and square compression and expansion modules */
> > > > - mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_BYPASS_1,
> > > > - MALI_C55_REG_BYPASS_1_FE_SQRT,
> > > > - MALI_C55_REG_BYPASS_1_FE_SQRT);
> > > > - mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_BYPASS_3,
> > > > - MALI_C55_REG_BYPASS_3_SQUARE_BE,
> > > > - MALI_C55_REG_BYPASS_3_SQUARE_BE);
> > > > -
> > > > - /* Bypass the temper module */
> > > > - mali_c55_ctx_write(mali_c55, MALI_C55_REG_BYPASS_2,
> > > > - MALI_C55_REG_BYPASS_2_TEMPER);
> > > > -
> > > > - /* Disable the temper module's DMA read/write */
> > > > - mali_c55_ctx_write(mali_c55, MALI_C55_REG_TEMPER_DMA_IO, 0x0);
> > > > -
> > > > - /* Bypass the colour noise reduction */
> > > > - mali_c55_ctx_write(mali_c55, MALI_C55_REG_BYPASS_4,
> > > > - MALI_C55_REG_BYPASS_4_CNR);
> > > > -
> > > > - /* Disable the sinter module */
> > > > - mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_SINTER_CONFIG,
> > > > - MALI_C55_SINTER_ENABLE_MASK, 0);
> > > > -
> > > > - /* Disable the RGB Gamma module for each output */
> > > > - mali_c55_ctx_write(mali_c55, MALI_C55_REG_FR_GAMMA_RGB_ENABLE, 0);
> > > > - mali_c55_ctx_write(mali_c55, MALI_C55_REG_DS_GAMMA_RGB_ENABLE, 0);
> > > > -
> > > > - /* Disable the colour correction matrix */
> > > > - mali_c55_ctx_write(mali_c55, MALI_C55_REG_CCM_ENABLE, 0);
> > > > -
> > > > return 0;
> > > > }
> > > > diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-isp.c b/drivers/media/platform/arm/mali-c55/mali-c55-isp.c
> > > > index 497f25fbdd13..4c0fd1ec741c 100644
> > > > --- a/drivers/media/platform/arm/mali-c55/mali-c55-isp.c
> > > > +++ b/drivers/media/platform/arm/mali-c55/mali-c55-isp.c
> > > > @@ -112,9 +112,6 @@ static int mali_c55_isp_start(struct mali_c55 *mali_c55,
> > > > const struct v4l2_subdev_state *state)
> > > > {
> > > > struct mali_c55_context *ctx = mali_c55_get_active_context(mali_c55);
> > > > - const struct mali_c55_isp_format_info *cfg;
> > > > - const struct v4l2_mbus_framefmt *format;
> > > > - const struct v4l2_rect *crop;
> > > > u32 val;
> > > > int ret;
> > > > @@ -122,35 +119,11 @@ static int mali_c55_isp_start(struct mali_c55 *mali_c55,
> > > > MALI_C55_REG_MCU_CONFIG_WRITE_MASK,
> > > > MALI_C55_REG_MCU_CONFIG_WRITE_PING);
> > > > - /* Apply input windowing */
> > > > - crop = v4l2_subdev_state_get_crop(state, MALI_C55_ISP_PAD_SINK_VIDEO);
> > > > - format = v4l2_subdev_state_get_format(state,
> > > > - MALI_C55_ISP_PAD_SINK_VIDEO);
> > > > - cfg = mali_c55_isp_get_mbus_config_by_code(format->code);
> > > > -
> > > > - mali_c55_write(mali_c55, MALI_C55_REG_HC_START,
> > > > - MALI_C55_HC_START(crop->left));
> > > > - mali_c55_write(mali_c55, MALI_C55_REG_HC_SIZE,
> > > > - MALI_C55_HC_SIZE(crop->width));
> > > > - mali_c55_write(mali_c55, MALI_C55_REG_VC_START_SIZE,
> > > > - MALI_C55_VC_START(crop->top) |
> > > > - MALI_C55_VC_SIZE(crop->height));
> > > > - mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_BASE_ADDR,
> > > > - MALI_C55_REG_ACTIVE_WIDTH_MASK, format->width);
> > > > - mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_BASE_ADDR,
> > > > - MALI_C55_REG_ACTIVE_HEIGHT_MASK,
> > > > - format->height << 16);
> > > > - mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_BAYER_ORDER,
> > > > - MALI_C55_BAYER_ORDER_MASK, cfg->order);
> > > > - mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_INPUT_WIDTH,
> > > > - MALI_C55_INPUT_WIDTH_MASK,
> > > > - MALI_C55_INPUT_WIDTH_20BIT);
> > > > -
> > > > - mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_ISP_RAW_BYPASS,
> > > > - MALI_C55_ISP_RAW_BYPASS_BYPASS_MASK,
> > > > - cfg->bypass ? MALI_C55_ISP_RAW_BYPASS_BYPASS_MASK :
> > > > - 0x00);
> > > > -
> > > > + /*
> > > > + * Apply default ISP configuration and the apply configurations from
> > > > + * the first available parameters buffer.
> > > > + */
> > > > + mali_c55_params_init_isp_config(mali_c55, state);
> > > > mali_c55_params_write_config(mali_c55);
> > > > ret = mali_c55_config_write(ctx, MALI_C55_CONFIG_PING, true);
> > > > if (ret) {
> > > > diff --git a/drivers/media/platform/arm/mali-c55/mali-c55-params.c b/drivers/media/platform/arm/mali-c55/mali-c55-params.c
> > > > index c03a6120ddbf..c84a6047a570 100644
> > > > --- a/drivers/media/platform/arm/mali-c55/mali-c55-params.c
> > > > +++ b/drivers/media/platform/arm/mali-c55/mali-c55-params.c
> > > > @@ -732,6 +732,78 @@ void mali_c55_params_write_config(struct mali_c55 *mali_c55)
> > > > vb2_buffer_done(&buf->vb.vb2_buf, VB2_BUF_STATE_DONE);
> > > > }
> > > > +void mali_c55_params_init_isp_config(struct mali_c55 *mali_c55,
> > > > + const struct v4l2_subdev_state *state)
> > > > +{
> > > > + const struct mali_c55_isp_format_info *cfg;
> > > > + const struct v4l2_mbus_framefmt *format;
> > > > + const struct v4l2_rect *crop;
> > > > +
> > > > + /* Apply input windowing */
> > > > + crop = v4l2_subdev_state_get_crop(state, MALI_C55_ISP_PAD_SINK_VIDEO);
> > > > + format = v4l2_subdev_state_get_format(state,
> > > > + MALI_C55_ISP_PAD_SINK_VIDEO);
> > > > + cfg = mali_c55_isp_get_mbus_config_by_code(format->code);
> > > > +
> > > > + mali_c55_write(mali_c55, MALI_C55_REG_HC_START,
> > > > + MALI_C55_HC_START(crop->left));
> > > > + mali_c55_write(mali_c55, MALI_C55_REG_HC_SIZE,
> > > > + MALI_C55_HC_SIZE(crop->width));
> > > > + mali_c55_write(mali_c55, MALI_C55_REG_VC_START_SIZE,
> > > > + MALI_C55_VC_START(crop->top) |
> > > > + MALI_C55_VC_SIZE(crop->height));
> > > > + mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_BASE_ADDR,
> > > > + MALI_C55_REG_ACTIVE_WIDTH_MASK, format->width);
> > > > + mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_BASE_ADDR,
> > > > + MALI_C55_REG_ACTIVE_HEIGHT_MASK,
> > > > + format->height << 16);
> > > > + mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_BAYER_ORDER,
> > > > + MALI_C55_BAYER_ORDER_MASK, cfg->order);
> > > > + mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_INPUT_WIDTH,
> > > > + MALI_C55_INPUT_WIDTH_MASK,
> > > > + MALI_C55_INPUT_WIDTH_20BIT);
> > > > +
> > > > + mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_ISP_RAW_BYPASS,
> > > > + MALI_C55_ISP_RAW_BYPASS_BYPASS_MASK,
> > > > + cfg->bypass ? MALI_C55_ISP_RAW_BYPASS_BYPASS_MASK :
> > > > + 0x00);
> > > > +
> > > > + /*
> > > > + * Some features of the ISP need to be disabled by default and only
> > > > + * enabled at the same time as they're configured by a parameters buffer
> > > > + */
> > > > +
> > > > + /* Bypass the sqrt and square compression and expansion modules */
> > > > + mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_BYPASS_1,
> > > > + MALI_C55_REG_BYPASS_1_FE_SQRT,
> > > > + MALI_C55_REG_BYPASS_1_FE_SQRT);
> > > > + mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_BYPASS_3,
> > > > + MALI_C55_REG_BYPASS_3_SQUARE_BE,
> > > > + MALI_C55_REG_BYPASS_3_SQUARE_BE);
> > > > +
> > > > + /* Bypass the temper module */
> > > > + mali_c55_ctx_write(mali_c55, MALI_C55_REG_BYPASS_2,
> > > > + MALI_C55_REG_BYPASS_2_TEMPER);
> > > > +
> > > > + /* Disable the temper module's DMA read/write */
> > > > + mali_c55_ctx_write(mali_c55, MALI_C55_REG_TEMPER_DMA_IO, 0x0);
> > > > +
> > > > + /* Bypass the colour noise reduction */
> > > > + mali_c55_ctx_write(mali_c55, MALI_C55_REG_BYPASS_4,
> > > > + MALI_C55_REG_BYPASS_4_CNR);
> > > > +
> > > > + /* Disable the sinter module */
> > > > + mali_c55_ctx_update_bits(mali_c55, MALI_C55_REG_SINTER_CONFIG,
> > > > + MALI_C55_SINTER_ENABLE_MASK, 0);
> > > > +
> > > > + /* Disable the RGB Gamma module for each output */
> > > > + mali_c55_ctx_write(mali_c55, MALI_C55_REG_FR_GAMMA_RGB_ENABLE, 0);
> > > > + mali_c55_ctx_write(mali_c55, MALI_C55_REG_DS_GAMMA_RGB_ENABLE, 0);
> > > > +
> > > > + /* Disable the colour correction matrix */
> > > > + mali_c55_ctx_write(mali_c55, MALI_C55_REG_CCM_ENABLE, 0);
> > > > +}
> > > > +
> > > > void mali_c55_unregister_params(struct mali_c55 *mali_c55)
> > > > {
> > > > struct mali_c55_params *params = &mali_c55->params;
> > > >
> > >
>
next prev parent reply other threads:[~2026-03-13 17:00 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-13 14:53 [PATCH v2 0/6] media: mali-c55: Fix ISP reset and blocks bypass Jacopo Mondi
2026-03-13 14:53 ` [PATCH v2 1/6] media: mali-c55: Fix wrong comment of ISP block types Jacopo Mondi
2026-03-13 16:22 ` Barnabás Pőcze
2026-03-13 14:53 ` [PATCH v2 2/6] media: mali-c55: Initialize the ISP in enable_streams() Jacopo Mondi
2026-03-13 15:59 ` Dan Scally
2026-03-13 16:10 ` Jacopo Mondi
2026-03-13 16:14 ` Dan Scally
2026-03-13 17:00 ` Jacopo Mondi [this message]
2026-03-16 9:34 ` Dan Scally
2026-03-13 14:53 ` [PATCH v2 3/6] media: mali-c55: Fully reset the ISP configuration Jacopo Mondi
2026-03-13 16:01 ` Dan Scally
2026-03-13 14:54 ` [PATCH v2 4/6] media: mali-c55: Fix Iridix bypass macros Jacopo Mondi
2026-03-13 14:54 ` [PATCH v2 5/6] media: mali-c55: Bypass the Iridix Tonemap engine Jacopo Mondi
2026-03-13 16:04 ` Dan Scally
2026-03-13 16:18 ` Barnabás Pőcze
2026-03-13 14:54 ` [PATCH v2 6/6] media: mali-c55: Bypass Purple Fringe Correction Jacopo Mondi
2026-03-13 16:04 ` Dan Scally
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