[PATCH v9 10/18] drm: bridge: samsung-dsim: Init exynos host for first DSI transfer
Jagan Teki
jagan at amarulasolutions.com
Tue Dec 13 21:33:23 PST 2022
On Tue, Dec 13, 2022 at 9:11 PM Marek Szyprowski
<m.szyprowski at samsung.com> wrote:
>
> On 13.12.2022 16:15, Jagan Teki wrote:
> > On Tue, Dec 13, 2022 at 8:24 PM Marek Szyprowski
> > <m.szyprowski at samsung.com> wrote:
> >> On 13.12.2022 15:18, Jagan Teki wrote:
> >>> On Tue, Dec 13, 2022 at 7:31 PM Marek Szyprowski
> >>> <m.szyprowski at samsung.com> wrote:
> >>>> On 13.12.2022 13:20, Marek Szyprowski wrote:
> >>>>> On 13.12.2022 11:40, Jagan Teki wrote:
> >>>>>> On Tue, Dec 13, 2022 at 2:28 PM Marek Szyprowski
> >>>>>> <m.szyprowski at samsung.com> wrote:
> >>>>>>> On 12.12.2022 16:33, Jagan Teki wrote:
> >>>>>>>
> >>>>>>> On Mon, Dec 12, 2022 at 8:52 PM Marek Szyprowski
> >>>>>>> <m.szyprowski at samsung.com> wrote:
> >>>>>>>
> >>>>>>> On 12.12.2022 09:43, Marek Szyprowski wrote:
> >>>>>>>
> >>>>>>> On 12.12.2022 09:32, Jagan Teki wrote:
> >>>>>>>
> >>>>>>> On Mon, Dec 12, 2022 at 1:56 PM Marek Szyprowski
> >>>>>>> <m.szyprowski at samsung.com> wrote:
> >>>>>>>
> >>>>>>> Hi Jagan,
> >>>>>>>
> >>>>>>> On 09.12.2022 16:23, Jagan Teki wrote:
> >>>>>>>
> >>>>>>> The existing drm panels and bridges in Exynos required host
> >>>>>>> initialization during the first DSI command transfer even though
> >>>>>>> the initialization was done before.
> >>>>>>>
> >>>>>>> This host reinitialization is handled via DSIM_STATE_REINITIALIZED
> >>>>>>> flag and triggers from host transfer.
> >>>>>>>
> >>>>>>> Do this exclusively for Exynos.
> >>>>>>>
> >>>>>>> Initial logic is derived from Marek Szyprowski changes.
> >>>>>>>
> >>>>>>> Signed-off-by: Marek Szyprowski <m.szyprowski at samsung.com>
> >>>>>>> Signed-off-by: Jagan Teki <jagan at amarulasolutions.com>
> >>>>>>> ---
> >>>>>>> Changes from v9:
> >>>>>>> - derived from v8
> >>>>>>> - added comments
> >>>>>>>
> >>>>>>> drivers/gpu/drm/bridge/samsung-dsim.c | 15 ++++++++++++++-
> >>>>>>> include/drm/bridge/samsung-dsim.h | 5 +++--
> >>>>>>> 2 files changed, 17 insertions(+), 3 deletions(-)
> >>>>>>>
> >>>>>>> The following chunk is missing compared to v8:
> >>>>>>>
> >>>>>>> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
> >>>>>>> b/drivers/gpu/drm/bridge/samsung-dsim.c
> >>>>>>> index 6e9ad955ebd3..6a9403cb92ae 100644
> >>>>>>> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> >>>>>>> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> >>>>>>> @@ -1315,7 +1315,9 @@ static int samsung_dsim_init(struct samsung_dsim
> >>>>>>> *dsi, unsigned int flag)
> >>>>>>> return 0;
> >>>>>>>
> >>>>>>> samsung_dsim_reset(dsi);
> >>>>>>> - samsung_dsim_enable_irq(dsi);
> >>>>>>> +
> >>>>>>> + if (!(dsi->state & DSIM_STATE_INITIALIZED))
> >>>>>>> + samsung_dsim_enable_irq(dsi);
> >>>>>>>
> >>>>>>> Is this really required? does it make sure that the IRQ does not
> >>>>>>> enable twice?
> >>>>>>>
> >>>>>>> That's what that check does. Without the 'if (!(dsi->state &
> >>>>>>> DSIM_STATE_INITIALIZED))' check, the irqs will be enabled twice (first
> >>>>>>> from pre_enable, then from the first transfer), what leads to a
> >>>>>>> warning from irq core.
> >>>>>>>
> >>>>>>> I've just noticed that we also would need to clear the
> >>>>>>> DSIM_STATE_REINITIALIZED flag in dsim_suspend.
> >>>>>>>
> >>>>>>> However I've found that a bit simpler patch would keep the current code
> >>>>>>> flow for Exynos instead of this reinitialization hack. This can be
> >>>>>>> applied on the "[PATCH v9 09/18] drm: bridge: samsung-dsim: Add host
> >>>>>>> init in pre_enable" patch:
> >>>>>>>
> >>>>>>> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
> >>>>>>> b/drivers/gpu/drm/bridge/samsung-dsim.c
> >>>>>>> index 0b2e52585485..acc95c61ae45 100644
> >>>>>>> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> >>>>>>> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> >>>>>>> @@ -1291,9 +1291,11 @@ static void
> >>>>>>> samsung_dsim_atomic_pre_enable(struct
> >>>>>>> drm_bridge *bridge,
> >>>>>>>
> >>>>>>> dsi->state |= DSIM_STATE_ENABLED;
> >>>>>>>
> >>>>>>> - ret = samsung_dsim_init(dsi, DSIM_STATE_INITIALIZED);
> >>>>>>> - if (ret)
> >>>>>>> - return;
> >>>>>>> + if (!samsung_dsim_hw_is_exynos(dsi->plat_data->hw_type)) {
> >>>>>>> + ret = samsung_dsim_init(dsi, DSIM_STATE_INITIALIZED);
> >>>>>>> + if (ret)
> >>>>>>> + return;
> >>>>>>> + }
> >>>>>>>
> >>>>>>> Sorry, I don't understand this. Does it mean Exynos doesn't need to
> >>>>>>> init host in pre_enable? If I remember correctly even though the host
> >>>>>>> is initialized it has to reinitialize during the first transfer - This
> >>>>>>> is what the Exynos requirement is. Please correct or explain here.
> >>>>>>>
> >>>>>>> This is a matter of enabling power regulator(s) in the right order
> >>>>>>> and doing the host initialization in the right moment. It was never
> >>>>>>> a matter of re-initialization. See the current code for the
> >>>>>>> reference (it uses the same approach as my above change). I've
> >>>>>>> already explained that here:
> >>>>>>>
> >>>>>>> https://lore.kernel.org/all/e96197f9-948a-997e-5453-9f9d179b5f5a@samsung.com/
> >>>>>>>
> >>>>>>>
> >>>>>>> If you would like to see the exact proper moment of the dsi host
> >>>>>>> initialization on the Exynos see the code here:
> >>>>>>>
> >>>>>>> https://protect2.fireeye.com/v1/url?k=5dc33900-0258001f-5dc2b24f-000babdfecba-f7c1a2a1905c83ca&q=1&e=f086bfdb-9055-48bd-b9c2-5dffb6c0d558&u=https%3A%2F%2Fgithub.com%2Fmszyprow%2Flinux%2Ftree%2Fv5.18-next-20220511-dsi-rework
> >>>>>>> and patches adding mipi_dsi_host_init() to panel/bridge drivers.
> >>>>>> As I said before, the downstream bridge needs an explicit call to host
> >>>>>> init via mipi_dsi_host_init - this is indeed not a usual use-case
> >>>>>> scenario. Let's handle this with a REINIT fix and see if we can update
> >>>>>> this later to handle both scenarios.
> >>>>>>
> >>>>>> Would you please test this repo, I have included all.
> >>>>>>
> >>>>>> https://gitlab.com/openedev/kernel/-/commits/imx8mm-dsi-v10
> >>>>> This doesn't work on TM2e board. Give me some time to find why...
> >>>>>
> >>>> The following change is missing in "drm: bridge: Generalize Exynos-DSI
> >>>> driver into a Samsung DSIM bridge" patch:
> >>>>
> >>>> diff --git a/drivers/gpu/drm/bridge/samsung-dsim.c
> >>>> b/drivers/gpu/drm/bridge/samsung-dsim.c
> >>>> index 1dbff2bee93f..81828b5ee0ac 100644
> >>>> --- a/drivers/gpu/drm/bridge/samsung-dsim.c
> >>>> +++ b/drivers/gpu/drm/bridge/samsung-dsim.c
> >>>> @@ -1745,6 +1745,7 @@ int samsung_dsim_probe(struct platform_device *pdev)
> >>>> dsi->bridge.funcs = &samsung_dsim_bridge_funcs;
> >>>> dsi->bridge.of_node = dev->of_node;
> >>>> dsi->bridge.type = DRM_MODE_CONNECTOR_DSI;
> >>>> + dsi->bridge.pre_enable_prev_first = true;
> >>> Can you check this and confirm, I keep this in exynos side.
> >>> https://gitlab.com/openedev/kernel/-/commit/ccb02df7a313fdf91d8e116b0ec3d6c945fbb6fd#c93f0ce4d81b854fbde970e341fb307f1be78c16_1865_189
> >> This one is fine!
> >>
> >>>> /* DE_LOW: i.MX8M Mini/Nano LCDIF-DSIM glue logic inverts
> >>>> HS/VS/DE */
> >>>> if (dsi->plat_data->hw_type == DSIM_TYPE_IMX8MM)
> >>>>
> >>>>
> >>>> After adding the above, all my test platform works fine.
> >>>>
> >>>> BTW, I still think that it is worth replacing the "drm: exynos: dsi: Add
> >>>> host initialization in pre_enable" patch with the following simple
> >>>> change and propagate it to bridge/samsung-dsim.c:
> >>>>
> >>>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> >>>> b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> >>>> index fdaf514b39f2..071b74d60dcb 100644
> >>>> --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> >>>> +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
> >>>> @@ -254,6 +254,9 @@ struct exynos_dsi_transfer {
> >>>> #define DSIM_STATE_CMD_LPM BIT(2)
> >>>> #define DSIM_STATE_VIDOUT_AVAILABLE BIT(3)
> >>>>
> >>>> +#define exynos_dsi_hw_is_exynos(hw) \
> >>>> + ((hw) >= DSIM_TYPE_EXYNOS3250 && (hw) <= DSIM_TYPE_EXYNOS5433)
> >>>> +
> >>>> enum exynos_dsi_type {
> >>>> DSIM_TYPE_EXYNOS3250,
> >>>> DSIM_TYPE_EXYNOS4210,
> >>>> @@ -1344,6 +1347,9 @@ static int exynos_dsi_init(struct exynos_dsi *dsi)
> >>>> {
> >>>> const struct exynos_dsi_driver_data *driver_data =
> >>>> dsi->driver_data;
> >>>>
> >>>> + if (dsi->state & DSIM_STATE_INITIALIZED)
> >>>> + return 0;
> >>>> +
> >>>> exynos_dsi_reset(dsi);
> >>>> exynos_dsi_enable_irq(dsi);
> >>>>
> >>>> @@ -1356,6 +1362,8 @@ static int exynos_dsi_init(struct exynos_dsi *dsi)
> >>>> exynos_dsi_set_phy_ctrl(dsi);
> >>>> exynos_dsi_init_link(dsi);
> >>>>
> >>>> + dsi->state |= DSIM_STATE_INITIALIZED;
> >>>> +
> >>>> return 0;
> >>>> }
> >>>>
> >>>> @@ -1411,6 +1419,12 @@ static void exynos_dsi_atomic_pre_enable(struct
> >>>> drm_bridge *bridge,
> >>>> }
> >>>>
> >>>> dsi->state |= DSIM_STATE_ENABLED;
> >>>> +
> >>>> + if (!exynos_dsi_hw_is_exynos(dsi->plat_data->hw_type)) {
> >>>> + ret = exynos_dsi_init(dsi);
> >>>> + if (ret)
> >>>> + return;
> >>>> + }
> >>>> }
> >>>>
> >>>> static void exynos_dsi_atomic_enable(struct drm_bridge *bridge,
> >>>> @@ -1557,12 +1571,9 @@ static ssize_t exynos_dsi_host_transfer(struct
> >>>> mipi_dsi_host *host,
> >>>> if (!(dsi->state & DSIM_STATE_ENABLED))
> >>>> return -EINVAL;
> >>>>
> >>>> - if (!(dsi->state & DSIM_STATE_INITIALIZED)) {
> >>>> - ret = exynos_dsi_init(dsi);
> >>>> - if (ret)
> >>>> - return ret;
> >>>> - dsi->state |= DSIM_STATE_INITIALIZED;
> >>>> - }
> >>>> + ret = exynos_dsi_init(dsi);
> >>>> + if (ret)
> >>>> + return ret;
> >>> Below patch handling similar behavior by checking exynos hw_type at
> >>> exynos_dsi_init, isn't it? Please check and let me know if I missing
> >>> anything.
> >>>
> >>> https://gitlab.com/openedev/kernel/-/commit/d19d491eef92b92e12a26265697274ce666eddb5
> >> You don't miss anything. Your version also works, but I just proposed a
> >> bit simpler code.
> > Do your changes don't need a DSIM_STATE_REINITIALIZED flag? would you
> > please share the change on top of this commit?
> > https://gitlab.com/openedev/kernel/-/commit/d19d491eef92b92e12a26265697274ce666eddb5
>
> It doesn't need the DSIM_STATE_REINITIALIZED flag because the
> initialization is done only once - in pre_enable for non-Exynos case and
> on the first transfer for the Exynos case. In both cases the same flag
> (DSIM_STATE_INITIALIZED) is used.
>
> See the attached patch.
Thanks, I have included the changes and added your authorship as well.
Please test this final version and let me know if you have any comments.
https://gitlab.com/openedev/kernel/-/commits/imx8mm-dsi-v10
Jagan.
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