Hi Daniel,

> -----Original Message-----
> From: Daniel Vetter [mailto:daniel.vet...@ffwll.ch] On Behalf Of Daniel
> Vetter
> Sent: Tuesday, January 09, 2018 1:38 AM
> To: Hyun Kwon <hy...@xilinx.com>
> Cc: dri-devel@lists.freedesktop.org; devicet...@vger.kernel.org; Michal
> Simek <michal.si...@xilinx.com>
> Subject: Re: [PATCH 02/10] drm: xlnx: Add xlnx crtc of Xilinx DRM KMS
> 
> On Thu, Jan 04, 2018 at 06:05:51PM -0800, Hyun Kwon wrote:
> > xlnx_crtc is a part of Xilinx DRM KMS and a layer that
> > provides some interface between the Xilinx DRM KMS and
> > crtc drivers.
> >
> > Signed-off-by: Hyun Kwon <hyun.k...@xilinx.com>
> 
> Personal style, but I don't see much value in these small helpers.
> Splitting them from the main driver at least makes reading the patches a
> bit harder. But no strong opinion, just a bikeshed, feel free to ignore
> :-)

I also don't, but some reviewers prefer this way. I'll leave it this way for 
now. :-)

Thanks,
-hyun

> -Daniel
> 
> > ---
> >  drivers/gpu/drm/xlnx/xlnx_crtc.c | 194
> +++++++++++++++++++++++++++++++++++++++
> >  drivers/gpu/drm/xlnx/xlnx_crtc.h |  70 ++++++++++++++
> >  2 files changed, 264 insertions(+)
> >  create mode 100644 drivers/gpu/drm/xlnx/xlnx_crtc.c
> >  create mode 100644 drivers/gpu/drm/xlnx/xlnx_crtc.h
> >
> > diff --git a/drivers/gpu/drm/xlnx/xlnx_crtc.c
> b/drivers/gpu/drm/xlnx/xlnx_crtc.c
> > new file mode 100644
> > index 0000000..57ee939
> > --- /dev/null
> > +++ b/drivers/gpu/drm/xlnx/xlnx_crtc.c
> > @@ -0,0 +1,194 @@
> > +/*
> > + * Xilinx DRM crtc driver
> > + *
> > + *  Copyright (C) 2017 - 2018 Xilinx, Inc.
> > + *
> > + *  Author: Hyun Woo Kwon <hyun.k...@xilinx.com>
> > + *
> > + * SPDX-License-Identifier: GPL-2.0
> > + */
> > +
> > +#include <drm/drmP.h>
> > +
> > +#include <linux/list.h>
> > +
> > +#include "xlnx_crtc.h"
> > +
> > +/*
> > + * Overview
> > + * --------
> > + *
> > + * The Xilinx CRTC layer is to enable the custom interface to CRTC drivers.
> > + * The interface is used by Xilinx DRM driver where it needs CRTC
> > + * functionailty. CRTC drivers should attach the desired callbacks
> > + * to struct xlnx_crtc and register the xlnx_crtc with correcsponding
> > + * drm_device. It's highly recommended CRTC drivers register all
> callbacks
> > + * even though many of them are optional.
> > + * The CRTC helper simply walks through the registered CRTC device,
> > + * and call the callbacks.
> > + */
> > +
> > +/**
> > + * struct xlnx_crtc_helper - Xilinx CRTC helper
> > + * @xlnx_crtcs: list of Xilinx CRTC devices
> > + * @lock: lock to protect @xlnx_crtcs
> > + * @drm: back pointer to DRM core
> > + */
> > +struct xlnx_crtc_helper {
> > +   struct list_head xlnx_crtcs;
> > +   struct mutex lock; /* lock for @xlnx_crtcs */
> > +   struct drm_device *drm;
> > +};
> > +
> > +#define XLNX_CRTC_MAX_HEIGHT_WIDTH UINT_MAX
> > +
> > +int xlnx_crtc_helper_enable_vblank(struct xlnx_crtc_helper *helper,
> > +                              unsigned int crtc_id)
> > +{
> > +   struct xlnx_crtc *crtc;
> > +
> > +   list_for_each_entry(crtc, &helper->xlnx_crtcs, list)
> > +           if (drm_crtc_index(&crtc->crtc) == crtc_id)
> > +                   if (crtc->enable_vblank)
> > +                           return crtc->enable_vblank(crtc);
> > +   return -ENODEV;
> > +}
> > +
> > +void xlnx_crtc_helper_disable_vblank(struct xlnx_crtc_helper *helper,
> > +                                unsigned int crtc_id)
> > +{
> > +   struct xlnx_crtc *crtc;
> > +
> > +   list_for_each_entry(crtc, &helper->xlnx_crtcs, list) {
> > +           if (drm_crtc_index(&crtc->crtc) == crtc_id) {
> > +                   if (crtc->disable_vblank)
> > +                           crtc->disable_vblank(crtc);
> > +                   return;
> > +           }
> > +   }
> > +}
> > +
> > +unsigned int xlnx_crtc_helper_get_align(struct xlnx_crtc_helper *helper)
> > +{
> > +   struct xlnx_crtc *crtc;
> > +   unsigned int align = 1, tmp;
> > +
> > +   list_for_each_entry(crtc, &helper->xlnx_crtcs, list) {
> > +           if (crtc->get_align) {
> > +                   tmp = crtc->get_align(crtc);
> > +                   align = ALIGN(align, tmp);
> > +           }
> > +   }
> > +
> > +   return align;
> > +}
> > +
> > +u64 xlnx_crtc_helper_get_dma_mask(struct xlnx_crtc_helper *helper)
> > +{
> > +   struct xlnx_crtc *crtc;
> > +   u64 mask = DMA_BIT_MASK(sizeof(dma_addr_t) * 8), tmp;
> > +
> > +   list_for_each_entry(crtc, &helper->xlnx_crtcs, list) {
> > +           if (crtc->get_dma_mask) {
> > +                   tmp = crtc->get_dma_mask(crtc);
> > +                   mask = min(mask, tmp);
> > +           }
> > +   }
> > +
> > +   return mask;
> > +}
> > +
> > +int xlnx_crtc_helper_get_max_width(struct xlnx_crtc_helper *helper)
> > +{
> > +   struct xlnx_crtc *crtc;
> > +   unsigned int width = XLNX_CRTC_MAX_HEIGHT_WIDTH, tmp;
> > +
> > +   list_for_each_entry(crtc, &helper->xlnx_crtcs, list) {
> > +           if (crtc->get_max_width) {
> > +                   tmp = crtc->get_max_width(crtc);
> > +                   width = min(width, tmp);
> > +           }
> > +   }
> > +
> > +   return width;
> > +}
> > +
> > +int xlnx_crtc_helper_get_max_height(struct xlnx_crtc_helper *helper)
> > +{
> > +   struct xlnx_crtc *crtc;
> > +   unsigned int height = XLNX_CRTC_MAX_HEIGHT_WIDTH, tmp;
> > +
> > +   list_for_each_entry(crtc, &helper->xlnx_crtcs, list) {
> > +           if (crtc->get_max_height) {
> > +                   tmp = crtc->get_max_height(crtc);
> > +                   height = min(height, tmp);
> > +           }
> > +   }
> > +
> > +   return height;
> > +}
> > +
> > +uint32_t xlnx_crtc_helper_get_format(struct xlnx_crtc_helper *helper)
> > +{
> > +   struct xlnx_crtc *crtc;
> > +   u32 format = 0, tmp;
> > +
> > +   list_for_each_entry(crtc, &helper->xlnx_crtcs, list) {
> > +           if (crtc->get_format) {
> > +                   tmp = crtc->get_format(crtc);
> > +                   if (format && format != tmp)
> > +                           return 0;
> > +                   format = tmp;
> > +           }
> > +   }
> > +
> > +   return format;
> > +}
> > +
> > +struct xlnx_crtc_helper *xlnx_crtc_helper_init(struct drm_device *drm)
> > +{
> > +   struct xlnx_crtc_helper *helper;
> > +
> > +   helper = devm_kzalloc(drm->dev, sizeof(*helper), GFP_KERNEL);
> > +   if (!helper)
> > +           return ERR_PTR(-ENOMEM);
> > +
> > +   INIT_LIST_HEAD(&helper->xlnx_crtcs);
> > +   mutex_init(&helper->lock);
> > +   helper->drm = drm;
> > +
> > +   return helper;
> > +}
> > +
> > +void xlnx_crtc_helper_fini(struct drm_device *drm,
> > +                      struct xlnx_crtc_helper *helper)
> > +{
> > +   if (WARN_ON(helper->drm != drm))
> > +           return;
> > +
> > +   if (WARN_ON(!list_empty(&helper->xlnx_crtcs)))
> > +           return;
> > +
> > +   mutex_destroy(&helper->lock);
> > +   devm_kfree(drm->dev, helper);
> > +}
> > +
> > +void xlnx_crtc_register(struct drm_device *drm, struct xlnx_crtc *crtc)
> > +{
> > +   struct xlnx_crtc_helper *helper = xlnx_get_crtc_helper(drm);
> > +
> > +   mutex_lock(&helper->lock);
> > +   list_add_tail(&crtc->list, &helper->xlnx_crtcs);
> > +   mutex_unlock(&helper->lock);
> > +}
> > +EXPORT_SYMBOL_GPL(xlnx_crtc_register);
> > +
> > +void xlnx_crtc_unregister(struct drm_device *drm, struct xlnx_crtc *crtc)
> > +{
> > +   struct xlnx_crtc_helper *helper = xlnx_get_crtc_helper(drm);
> > +
> > +   mutex_lock(&helper->lock);
> > +   list_del(&crtc->list);
> > +   mutex_unlock(&helper->lock);
> > +}
> > +EXPORT_SYMBOL_GPL(xlnx_crtc_unregister);
> > diff --git a/drivers/gpu/drm/xlnx/xlnx_crtc.h
> b/drivers/gpu/drm/xlnx/xlnx_crtc.h
> > new file mode 100644
> > index 0000000..db7404e
> > --- /dev/null
> > +++ b/drivers/gpu/drm/xlnx/xlnx_crtc.h
> > @@ -0,0 +1,70 @@
> > +/*
> > + * Xilinx DRM crtc header
> > + *
> > + *  Copyright (C) 2017 - 2018 Xilinx, Inc.
> > + *
> > + *  Author: Hyun Woo Kwon <hyun.k...@xilinx.com>
> > + *
> > + * SPDX-License-Identifier: GPL-2.0
> > + */
> > +
> > +#ifndef _XLNX_CRTC_H_
> > +#define _XLNX_CRTC_H_
> > +
> > +/**
> > + * struct xlnx_crtc - Xilinx CRTC device
> > + * @crtc: DRM CRTC device
> > + * @list: list node for Xilinx CRTC device list
> > + * @enable_vblank: Enable vblank
> > + * @disable_vblank: Disable vblank
> > + * @get_align: Get the alignment requirement of CRTC device
> > + * @get_dma_mask: Get the dma mask of CRTC device
> > + * @get_max_width: Get the maximum supported width
> > + * @get_max_height: Get the maximum supported height
> > + * @get_format: Get the current format of CRTC device
> > + */
> > +struct xlnx_crtc {
> > +   struct drm_crtc crtc;
> > +   struct list_head list;
> > +   int (*enable_vblank)(struct xlnx_crtc *crtc);
> > +   void (*disable_vblank)(struct xlnx_crtc *crtc);
> > +   unsigned int (*get_align)(struct xlnx_crtc *crtc);
> > +   u64 (*get_dma_mask)(struct xlnx_crtc *crtc);
> > +   int (*get_max_width)(struct xlnx_crtc *crtc);
> > +   int (*get_max_height)(struct xlnx_crtc *crtc);
> > +   uint32_t (*get_format)(struct xlnx_crtc *crtc);
> > +};
> > +
> > +/*
> > + * Helper functions: used within Xlnx DRM
> > + */
> > +
> > +struct xlnx_crtc_helper;
> > +
> > +int xlnx_crtc_helper_enable_vblank(struct xlnx_crtc_helper *helper,
> > +                              unsigned int crtc_id);
> > +void xlnx_crtc_helper_disable_vblank(struct xlnx_crtc_helper *helper,
> > +                                unsigned int crtc_id);
> > +unsigned int xlnx_crtc_helper_get_align(struct xlnx_crtc_helper *helper);
> > +u64 xlnx_crtc_helper_get_dma_mask(struct xlnx_crtc_helper *helper);
> > +int xlnx_crtc_helper_get_max_width(struct xlnx_crtc_helper *helper);
> > +int xlnx_crtc_helper_get_max_height(struct xlnx_crtc_helper *helper);
> > +uint32_t xlnx_crtc_helper_get_format(struct xlnx_crtc_helper *helper);
> > +
> > +struct xlnx_crtc_helper *xlnx_crtc_helper_init(struct drm_device *drm);
> > +void xlnx_crtc_helper_fini(struct drm_device *drm,
> > +                      struct xlnx_crtc_helper *helper);
> > +
> > +/*
> > + * CRTC registration: used by other sub-driver modules
> > + */
> > +
> > +static inline struct xlnx_crtc *to_xlnx_crtc(struct drm_crtc *crtc)
> > +{
> > +   return container_of(crtc, struct xlnx_crtc, crtc);
> > +}
> > +
> > +void xlnx_crtc_register(struct drm_device *drm, struct xlnx_crtc *crtc);
> > +void xlnx_crtc_unregister(struct drm_device *drm, struct xlnx_crtc
> *crtc);
> > +
> > +#endif /* _XLNX_CRTC_H_ */
> > --
> > 2.7.4
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/dri-devel
> 
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> http://blog.ffwll.ch
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