We register the simplekms device with the DRM platform helpers. A
native driver for the graphics hardware will kickout the simplekms
driver before taking over the device.
Signed-off-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
---
drivers/gpu/drm/tiny/Kconfig | 1 +
drivers/gpu/drm/tiny/simplekms.c | 94 +++++++++++++++++++++++++++++++-
2 files changed, 92 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/tiny/Kconfig b/drivers/gpu/drm/tiny/Kconfig
index 50dbde8bdcb2..a47ed337a7fe 100644
--- a/drivers/gpu/drm/tiny/Kconfig
+++ b/drivers/gpu/drm/tiny/Kconfig
@@ -33,6 +33,7 @@ config DRM_SIMPLEKMS
depends on DRM
select DRM_GEM_SHMEM_HELPER
select DRM_KMS_HELPER
+ select DRM_PLATFORM_HELPER
help
DRM driver for simple platform-provided framebuffers.
diff --git a/drivers/gpu/drm/tiny/simplekms.c b/drivers/gpu/drm/tiny/simplekms.c
index ae5d3cbadbe8..a903a4e0100a 100644
--- a/drivers/gpu/drm/tiny/simplekms.c
+++ b/drivers/gpu/drm/tiny/simplekms.c
@@ -5,6 +5,7 @@
#include <linux/platform_data/simplefb.h>
#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
+#include <linux/spinlock.h>
#include <drm/drm_atomic_state_helper.h>
#include <drm/drm_connector.h>
@@ -17,6 +18,7 @@
#include <drm/drm_gem_shmem_helper.h>
#include <drm/drm_managed.h>
#include <drm/drm_modeset_helper_vtables.h>
+#include <drm/drm_platform.h>
#include <drm/drm_probe_helper.h>
#include <drm/drm_simple_kms_helper.h>
@@ -36,6 +38,12 @@
#define SIMPLEKMS_MODE(hd, vd) \
DRM_SIMPLE_MODE(hd, vd, RES_MM(hd), RES_MM(vd))
+/*
+ * Protects the platform device's drvdata against
+ * concurrent manipulation.
+ */
+static DEFINE_SPINLOCK(simplekms_drvdata_lock);
+
/*
* Helpers for simplefb
*/
@@ -211,6 +219,7 @@ struct simplekms_device {
unsigned int pitch;
/* memory management */
+ struct drm_aperture *aperture;
struct resource *mem;
void __iomem *screen_base;
@@ -224,6 +233,8 @@ static struct simplekms_device *simplekms_device_of_dev(struct drm_device *dev)
return container_of(dev, struct simplekms_device, dev);
}
+static void simplekms_device_cleanup(struct simplekms_device *sdev);
+
/*
* Hardware
*/
@@ -514,22 +525,72 @@ static int simplekms_device_init_fb(struct simplekms_device *sdev)
* Memory management
*/
+static void simplekms_aperture_kickout(struct drm_aperture *ap)
+{
+ struct drm_device *dev = ap->dev;
+ struct simplekms_device *sdev = simplekms_device_of_dev(dev);
+ struct platform_device *pdev = sdev->pdev;
+
+ if (WARN_ON(!sdev->aperture))
+ return; /* BUG: driver already got kicked out */
+
+ drm_dev_unregister(dev);
+
+ sdev->aperture = NULL; /* memory is released by platform helpers */
+
+ spin_lock(&simplekms_drvdata_lock);
+ sdev = platform_get_drvdata(pdev);
+ platform_set_drvdata(pdev, NULL); /* required; see simplekms_remove() */
+ spin_unlock(&simplekms_drvdata_lock);
+
+ /*
+ * Return if a concurrent simplekms_remove() cleans up the
+ * device. See simplekms_remove().
+ */
+ if (!sdev)
+ return;
+
+ /*
+ * After the aperture has been released, there's no reason
+ * to keep the DRM device around.
+ */
+ simplekms_device_cleanup(sdev);
+}
+
+static const struct drm_aperture_funcs simplekms_aperture_funcs = {
+ .kickout = simplekms_aperture_kickout,
+};
+
static int simplekms_device_init_mm(struct simplekms_device *sdev)
{
+ struct drm_device *dev = &sdev->dev;
struct platform_device *pdev = sdev->pdev;
struct resource *mem;
+ struct drm_aperture *ap;
void __iomem *screen_base;
+ int ret;
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem)
return -EINVAL;
+ ap = drmm_aperture_acquire(dev, mem->start, resource_size(mem),
+ &simplekms_aperture_funcs);
+ if (IS_ERR(ap)) {
+ ret = PTR_ERR(ap);
+ 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)
return -ENOMEM;
sdev->mem = mem;
+ sdev->aperture = ap;
sdev->screen_base = screen_base;
return 0;
@@ -625,6 +686,9 @@ simplekms_simple_display_pipe_enable(struct drm_simple_display_pipe *pipe,
struct drm_framebuffer *fb = state->fb;
void *vmap;
+ if (!sdev->aperture)
+ return;
+
vmap = drm_gem_shmem_vmap(fb->obj[0]);
if (!vmap)
return;
@@ -645,6 +709,9 @@ simplekms_simple_display_pipe_update(struct drm_simple_display_pipe *pipe,
struct drm_rect clip;
void *vmap;
+ if (!sdev->aperture)
+ return;
+
if (!drm_atomic_helper_damage_merged(old_plane_state, state, &clip))
return;
@@ -716,11 +783,12 @@ static int simplekms_device_init_modeset(struct simplekms_device *sdev)
* Init / Cleanup
*/
-static void simplekms_device_cleanup(struct simplekms_device* sdev)
+static void simplekms_device_cleanup(struct simplekms_device *sdev)
{
struct drm_device *dev = &sdev->dev;
- drm_dev_unregister(dev);
+ if (dev->registered)
+ drm_dev_unregister(dev);
}
static struct simplekms_device *
@@ -797,7 +865,27 @@ static int simplekms_probe(struct platform_device *pdev)
static int simplekms_remove(struct platform_device *pdev)
{
- struct simplekms_device *sdev = platform_get_drvdata(pdev);
+ struct simplekms_device *sdev;
+
+ spin_lock(&simplekms_drvdata_lock);
+ sdev = platform_get_drvdata(pdev);
+ platform_set_drvdata(pdev, NULL);
+ spin_unlock(&simplekms_drvdata_lock);
+
+ /*
+ * The platform driver shares its reference to dev with the
+ * platform helpers for apertures. That reference is either
+ * released here when unloading the driver; or it's released
+ * when the driver gets kicked out by another driver. In the
+ * latter case, the aperture release routine clears the data
+ * field of the platform device.
+ *
+ * Therefore, sdev being NULL is a valid state if the driver
+ * has been kicked out by another DRM driver. In this case,
+ * it's all been cleaned up and we can return immediately.
+ */
+ if (!sdev)
+ return 0;
simplekms_device_cleanup(sdev);
--
2.27.0
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