[PATCH v4 9/9] drm/simpledrm: Acquire memory aperture for framebuffer

Thomas Zimmermann
2021-04-16T09:00:59Z

We register the simplekms device with the DRM platform helpers. A
native driver for the graphics hardware will kick-out the simpledrm
driver before taking over the device.

The original generic platform device from the simple-framebuffer boot
code will be unregistered. The native driver will use whatever native
hardware device it received.

v4:
* convert to drm_aperture_acquire_from_firmware()
v3:
* use platform_device_unregister() and handle detachment
like hot-unplug event (Daniel)
v2:
* adapt to aperture changes
* use drm_dev_unplug() and drm_dev_enter/exit()
* don't split error string

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Tested-by: nerdopolis <bluescreen_avenger@verizon.net>
---
drivers/gpu/drm/tiny/simpledrm.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/tiny/simpledrm.c b/drivers/gpu/drm/tiny/simpledrm.c
index 9d522473cd7c..2bdb477d9326 100644
--- a/drivers/gpu/drm/tiny/simpledrm.c
+++ b/drivers/gpu/drm/tiny/simpledrm.c
@@ -6,6 +6,7 @@
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>

+#include <drm/drm_aperture.h>
#include <drm/drm_atomic_state_helper.h>
#include <drm/drm_connector.h>
#include <drm/drm_damage_helper.h>
@@ -517,14 +518,23 @@ static int simpledrm_device_init_fb(struct simpledrm_device *sdev)

static int simpledrm_device_init_mm(struct simpledrm_device *sdev)
{
+ struct drm_device *dev = &sdev->dev;
struct platform_device *pdev = sdev->pdev;
struct resource *mem;
void __iomem *screen_base;
+ int ret;

mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem)
return -EINVAL;

+ ret = devm_aperture_acquire_from_firmware(dev, mem->start, resource_size(mem));
+ if (ret) {
+ drm_err(dev, "could not acquire memory range [0x%llx:0x%llx]: error %d\n",
+ mem->start, mem->end, ret);
+ return ret;
+ }
+
screen_base = devm_ioremap_wc(&pdev->dev, mem->start,
resource_size(mem));
if (!screen_base)
@@ -625,12 +635,18 @@ simpledrm_simple_display_pipe_enable(struct drm_simple_display_pipe *pipe,
struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
struct drm_framebuffer *fb = plane_state->fb;
void *vmap = shadow_plane_state->map[0].vaddr; /* TODO: Use mapping abstraction properly */
+ struct drm_device *dev = &sdev->dev;
+ int idx;

if (!fb)
return;

+ if (!drm_dev_enter(dev, &idx))
+ return;
+
drm_fb_blit_dstclip(sdev->screen_base, sdev->pitch,
sdev->format->format, vmap, fb);
+ drm_dev_exit(idx);
}

static void
@@ -658,7 +674,9 @@ simpledrm_simple_display_pipe_update(struct drm_simple_display_pipe *pipe,
struct drm_shadow_plane_state *shadow_plane_state = to_drm_shadow_plane_state(plane_state);
void *vmap = shadow_plane_state->map[0].vaddr; /* TODO: Use mapping abstraction properly */
struct drm_framebuffer *fb = plane_state->fb;
+ struct drm_device *dev = &sdev->dev;
struct drm_rect clip;
+ int idx;

if (!fb)
return;
@@ -666,8 +684,13 @@ simpledrm_simple_display_pipe_update(struct drm_simple_display_pipe *pipe,
if (!drm_atomic_helper_damage_merged(old_plane_state, plane_state, &clip))
return;

+ if (!drm_dev_enter(dev, &idx))
+ return;
+
drm_fb_blit_rect_dstclip(sdev->screen_base, sdev->pitch,
sdev->format->format, vmap, fb, &clip);
+
+ drm_dev_exit(idx);
}

static const struct drm_simple_display_pipe_funcs
@@ -847,7 +870,7 @@ static int simpledrm_remove(struct platform_device *pdev)
struct simpledrm_device *sdev = platform_get_drvdata(pdev);
struct drm_device *dev = &sdev->dev;

- drm_dev_unregister(dev);
+ drm_dev_unplug(dev);

return 0;
}
--
2.31.1