Date:   Sat, 29 Aug 2020 00:04:34 +0800
From:   Kevin Tang <kevin3.tang@...il.com>
To:     Sam Ravnborg <sam@...nborg.org>
Cc:     Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Sean Paul <sean@...rly.run>, David Airlie <airlied@...ux.ie>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Orson Zhai <orsonzhai@...il.com>,
        "Linux-Kernel@...r. Kernel. Org" <linux-kernel@...r.kernel.org>,
        ML dri-devel <dri-devel@...ts.freedesktop.org>,
        Chunyan Zhang <zhang.lyra@...il.com>
Subject: Re: [PATCH RFC v6 2/6] drm/sprd: add Unisoc's drm kms master

Sam Ravnborg <sam@...nborg.org> 于2020年7月29日周三 上午4:45写道：
>
> Hi Kevin.
>
> Nice split of the driver.
> Some feedback in the following.
> Most to bring the driver up-to-date with what have happened since
> we saw it last time.
> Keeping up with the changes in drm is not always easy.
>
>         Sam
>
Hi Sam,
Thanks for your feedback,
I am really busy sometimes, but will try my best to keep up with others.

>
> On Tue, Jul 28, 2020 at 06:07:55PM +0800, Kevin Tang wrote:
> > From: Kevin Tang <kevin.tang@...soc.com>
> >
> > Adds drm support for the Unisoc's display subsystem.
> >
> > This is drm kms driver, this driver provides support for the
> > application framework in Android, Yocto and more.
> >
> > Application framework can access Unisoc's display internel
> > peripherals through libdrm or libkms, it's test ok by modetest
> > (DRM/KMS test tool) and Android HWComposer.
> >
> > Cc: Orson Zhai <orsonzhai@...il.com>
> > Cc: Chunyan Zhang <zhang.lyra@...il.com>
> > Signed-off-by: Kevin Tang <kevin.tang@...soc.com>
> > ---
> >  drivers/gpu/drm/Kconfig         |   2 +
> >  drivers/gpu/drm/Makefile        |   1 +
> >  drivers/gpu/drm/sprd/Kconfig    |  12 +++
> >  drivers/gpu/drm/sprd/Makefile   |   5 +
> >  drivers/gpu/drm/sprd/sprd_drm.c | 226 ++++++++++++++++++++++++++++++++++++++++
> >  drivers/gpu/drm/sprd/sprd_drm.h |  16 +++
> >  6 files changed, 262 insertions(+)
> >  create mode 100644 drivers/gpu/drm/sprd/Kconfig
> >  create mode 100644 drivers/gpu/drm/sprd/Makefile
> >  create mode 100644 drivers/gpu/drm/sprd/sprd_drm.c
> >  create mode 100644 drivers/gpu/drm/sprd/sprd_drm.h
> >
> > diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
> > index c4fd57d..7fe7ab91 100644
> > --- a/drivers/gpu/drm/Kconfig
> > +++ b/drivers/gpu/drm/Kconfig
> > @@ -386,6 +386,8 @@ source "drivers/gpu/drm/mcde/Kconfig"
> >
> >  source "drivers/gpu/drm/tidss/Kconfig"
> >
> > +source "drivers/gpu/drm/sprd/Kconfig"
> > +
> >  # Keep legacy drivers last
> >
> >  menuconfig DRM_LEGACY
> > diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
> > index 2c0e5a7..ee2ccd9 100644
> > --- a/drivers/gpu/drm/Makefile
> > +++ b/drivers/gpu/drm/Makefile
> > @@ -123,3 +123,4 @@ obj-$(CONFIG_DRM_PANFROST) += panfrost/
> >  obj-$(CONFIG_DRM_ASPEED_GFX) += aspeed/
> >  obj-$(CONFIG_DRM_MCDE) += mcde/
> >  obj-$(CONFIG_DRM_TIDSS) += tidss/
> > +obj-$(CONFIG_DRM_SPRD) += sprd/
> > diff --git a/drivers/gpu/drm/sprd/Kconfig b/drivers/gpu/drm/sprd/Kconfig
> > new file mode 100644
> > index 0000000..b189a54
> > --- /dev/null
> > +++ b/drivers/gpu/drm/sprd/Kconfig
> > @@ -0,0 +1,12 @@
> > +config DRM_SPRD
> > +     tristate "DRM Support for Unisoc SoCs Platform"
> > +     depends on ARCH_SPRD || COMPILE_TEST
> > +     depends on DRM && OF
> > +     select DRM_KMS_HELPER
> > +     select DRM_GEM_CMA_HELPER
> > +     select DRM_KMS_CMA_HELPER
> > +     select DRM_MIPI_DSI
> > +     help
> > +       Choose this option if you have a Unisoc chipsets.
> > +       If M is selected the module will be called sprd-drm.
> > +
> > diff --git a/drivers/gpu/drm/sprd/Makefile b/drivers/gpu/drm/sprd/Makefile
> > new file mode 100644
> > index 0000000..86d95d9
> > --- /dev/null
> > +++ b/drivers/gpu/drm/sprd/Makefile
> > @@ -0,0 +1,5 @@
> > +# SPDX-License-Identifier: GPL-2.0
> > +
> > +subdir-ccflags-y += -I$(srctree)/$(src)
> subdir-ccflags-y is not needed - drop it.
>
> > +
> > +obj-y := sprd_drm.o
> > diff --git a/drivers/gpu/drm/sprd/sprd_drm.c b/drivers/gpu/drm/sprd/sprd_drm.c
> > new file mode 100644
> > index 0000000..4706185
> > --- /dev/null
> > +++ b/drivers/gpu/drm/sprd/sprd_drm.c
> > @@ -0,0 +1,226 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/*
> > + * Copyright (C) 2020 Unisoc Inc.
> > + */
> > +
> > +#include <linux/component.h>
> > +#include <linux/dma-mapping.h>
> > +#include <linux/module.h>
> > +#include <linux/mutex.h>
> > +#include <linux/of_graph.h>
> > +#include <linux/of_platform.h>
> > +
> > +#include <drm/drm_atomic_helper.h>
> > +#include <drm/drm_crtc_helper.h>
> > +#include <drm/drm_drv.h>
> > +#include <drm/drm_gem_cma_helper.h>
> > +#include <drm/drm_gem_framebuffer_helper.h>
> > +#include <drm/drm_of.h>
> > +#include <drm/drm_probe_helper.h>
> > +#include <drm/drm_vblank.h>
> > +
> > +#include "sprd_drm.h"
> > +
> > +#define DRIVER_NAME  "sprd"
> > +#define DRIVER_DESC  "Spreadtrum SoCs' DRM Driver"
> > +#define DRIVER_DATE  "20200201"
> > +#define DRIVER_MAJOR 1
> > +#define DRIVER_MINOR 0
> > +
> > +static const struct drm_mode_config_helper_funcs sprd_drm_mode_config_helper = {
> > +     .atomic_commit_tail = drm_atomic_helper_commit_tail_rpm,
> > +};
> > +
> > +static const struct drm_mode_config_funcs sprd_drm_mode_config_funcs = {
> > +     .fb_create = drm_gem_fb_create,
> > +     .atomic_check = drm_atomic_helper_check,
> > +     .atomic_commit = drm_atomic_helper_commit,
> > +};
> > +
> > +static void sprd_drm_mode_config_init(struct drm_device *drm)
> > +{
> > +     drm_mode_config_init(drm);
> The documentation of this functions says:
>
> FIXME: This function is deprecated and drivers should be converted over to
> drmm_mode_config_init().
>
>
> > +
> > +     drm->mode_config.min_width = 0;
> > +     drm->mode_config.min_height = 0;
> > +     drm->mode_config.max_width = 8192;
> > +     drm->mode_config.max_height = 8192;
> > +     drm->mode_config.allow_fb_modifiers = true;
> > +
> > +     drm->mode_config.funcs = &sprd_drm_mode_config_funcs;
> > +     drm->mode_config.helper_private = &sprd_drm_mode_config_helper;
> > +}
> > +
> > +DEFINE_DRM_GEM_CMA_FOPS(sprd_drm_fops);
> > +
> > +static struct drm_driver sprd_drm_drv = {
> > +     .driver_features        = DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
> > +     .fops                   = &sprd_drm_fops,
> > +
> > +     /* GEM Operations */
> > +     DRM_GEM_CMA_VMAP_DRIVER_OPS,
> > +
> > +     .name                   = DRIVER_NAME,
> > +     .desc                   = DRIVER_DESC,
> > +     .date                   = DRIVER_DATE,
> > +     .major                  = DRIVER_MAJOR,
> > +     .minor                  = DRIVER_MINOR,
> > +};
> > +
> > +static int sprd_drm_bind(struct device *dev)
> > +{
> > +     struct drm_device *drm;
> > +     struct sprd_drm *sprd;
> > +     int err;
> > +
> > +     drm = drm_dev_alloc(&sprd_drm_drv, dev);
> > +     if (IS_ERR(drm))
> > +             return PTR_ERR(drm);
> > +
> > +     dev_set_drvdata(dev, drm);
> > +
> > +     sprd = devm_kzalloc(drm->dev, sizeof(*sprd), GFP_KERNEL);
> > +     if (!sprd)
> > +             err = -ENOMEM;
>
> Embed drm_device in sprd_drm and use devm_drm_dev_alloc
> See other drivers and drm_drv.c how to do it.
> drm_drv.c has a nice example explained in one of the comment blocks.
>
> > +
> > +     drm->dev_private = sprd;
> dev_private is deprecated. Alwyas use upclassing.
dev_private is deprecated ? I see everyone is still using it, so it
will be deprecated in the future?
>
> > +
> > +     sprd_drm_mode_config_init(drm);
> > +
> > +     /* bind and init sub drivers */
> > +     err = component_bind_all(drm->dev, drm);
> > +     if (err) {
> > +             DRM_ERROR("failed to bind all component.\n");
> > +             goto err_dc_cleanup;
> > +     }
> > +
> > +     /* vblank init */
> > +     err = drm_vblank_init(drm, drm->mode_config.num_crtc);
> > +     if (err) {
> > +             DRM_ERROR("failed to initialize vblank.\n");
> > +             goto err_unbind_all;
> > +     }
> > +     /* with irq_enabled = true, we can use the vblank feature. */
> > +     drm->irq_enabled = true;
> Can drm_irq_install() be used?
> Then this flag shall not be set by the driver, And the interrupt numbers on different Soc are not necessarily the same
>
We need to set "IRQ_NOAUTOEN" flag for CRTC IRQ, you can see that we
manually turn the interrupt on and off by crtc
atomic_enable/atomic_disable
and the interrupt number on different Soc are not necessarily the
same. So intall interrupt in kms maybe is not suitable for us...
> > +
> > +     /* reset all the states of crtc/plane/encoder/connector */
> > +     drm_mode_config_reset(drm);
> > +
> > +     /* init kms poll for handling hpd */
> > +     drm_kms_helper_poll_init(drm);
> > +
> > +     err = drm_dev_register(drm, 0);
> > +     if (err < 0)
> > +             goto err_kms_helper_poll_fini;
> > +
> > +     return 0;
> > +
> > +err_kms_helper_poll_fini:
> > +     drm_kms_helper_poll_fini(drm);
> > +err_unbind_all:
> > +     component_unbind_all(drm->dev, drm);
> > +err_dc_cleanup:
> > +     drm_mode_config_cleanup(drm);
> > +     return err;
> > +}
> > +
> > +static void sprd_drm_unbind(struct device *dev)
> > +{
> > +     struct drm_device *drm = dev_get_drvdata(dev);
> > +
> > +     drm_dev_unregister(drm);
> > +
> > +     drm_kms_helper_poll_fini(drm);
> > +
> > +     drm_mode_config_cleanup(drm);
> > +
> > +     component_unbind_all(drm->dev, drm);
> > +     drm->dev_private = NULL;
> > +     dev_set_drvdata(dev, NULL);
> > +
> > +     drm_dev_put(drm);
> > +}
> > +
> > +static const struct component_master_ops drm_component_ops = {
> > +     .bind = sprd_drm_bind,
> > +     .unbind = sprd_drm_unbind,
> > +};
> > +
> > +static int compare_of(struct device *dev, void *data)
> > +{
> > +     return dev->of_node == data;
> > +}
> > +
> > +static int sprd_drm_probe(struct platform_device *pdev)
> > +{
> > +     int ret;
> > +
> > +     ret = dma_set_mask_and_coherent(&pdev->dev, ~0);
> > +     if (ret) {
> > +             DRM_ERROR("dma_set_mask_and_coherent failed (%d)\n", ret);
> > +             return ret;
> > +     }
> > +
> > +     return drm_of_component_probe(&pdev->dev, compare_of, &drm_component_ops);
> > +}
> > +
> > +static int sprd_drm_remove(struct platform_device *pdev)
> > +{
> > +     component_master_del(&pdev->dev, &drm_component_ops);
> > +     return 0;
> > +}
> > +
> > +static void sprd_drm_shutdown(struct platform_device *pdev)
> > +{
> > +     struct drm_device *drm = platform_get_drvdata(pdev);
> > +
> > +     if (!drm) {
> > +             DRM_WARN("drm device is not available, no shutdown\n");
> > +             return;
> > +     }
> > +
> > +     drm_atomic_helper_shutdown(drm);
> > +}
> > +
> > +static const struct of_device_id drm_match_table[] = {
> > +     { .compatible = "sprd,display-subsystem", },
> > +     { /* sentinel */ },
> > +};
> > +MODULE_DEVICE_TABLE(of, drm_match_table);
> > +
> > +static struct platform_driver sprd_drm_driver = {
> > +     .probe = sprd_drm_probe,
> > +     .remove = sprd_drm_remove,
> > +     .shutdown = sprd_drm_shutdown,
> > +     .driver = {
> > +             .name = "sprd-drm-drv",
> > +             .of_match_table = drm_match_table,
> > +     },
> > +};
> > +
> > +static struct platform_driver *sprd_drm_drivers[]  = {
> > +     &sprd_drm_driver,
> > +};
> > +
> > +static int __init sprd_drm_init(void)
> > +{
> > +     int ret;
> > +
> > +     ret = platform_register_drivers(sprd_drm_drivers,
> > +                                     ARRAY_SIZE(sprd_drm_drivers));
> > +     return ret;
> > +}
> > +
> > +static void __exit sprd_drm_exit(void)
> > +{
> > +     platform_unregister_drivers(sprd_drm_drivers,
> > +                                 ARRAY_SIZE(sprd_drm_drivers));
> > +}
> > +
> > +module_init(sprd_drm_init);
> > +module_exit(sprd_drm_exit);
> > +
> > +MODULE_AUTHOR("Leon He <leon.he@...soc.com>");
> > +MODULE_AUTHOR("Kevin Tang <kevin.tang@...soc.com>");
> > +MODULE_DESCRIPTION("Unisoc DRM KMS Master Driver");
> > +MODULE_LICENSE("GPL v2");
> > diff --git a/drivers/gpu/drm/sprd/sprd_drm.h b/drivers/gpu/drm/sprd/sprd_drm.h
> > new file mode 100644
> > index 0000000..edf0881
> > --- /dev/null
> > +++ b/drivers/gpu/drm/sprd/sprd_drm.h
> > @@ -0,0 +1,16 @@
> > +/* SPDX-License-Identifier: GPL-2.0 */
> > +/*
> > + * Copyright (C) 2020 Unisoc Inc.
> > + */
> > +
> > +#ifndef _SPRD_DRM_H_
> > +#define _SPRD_DRM_H_
> > +
> > +#include <drm/drm_atomic.h>
> > +#include <drm/drm_print.h>
> > +
> > +struct sprd_drm {
> > +     struct drm_device *drm;
> > +};
> > +
> > +#endif /* _SPRD_DRM_H_ */
> > --
> > 2.7.4
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@...ts.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel

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