drivers: display: enable direct framebuffer rendering with DCNANO LCDIF
Enable direct framebuffer rendering using DCNANO LCDIF, to improve
performance when the call to display_write is attempting to refresh
the full display.
Signed-off-by: Daniel DeGrasse <daniel.degrasse@nxp.com>
diff --git a/drivers/display/Kconfig.mcux_dcnano_lcdif b/drivers/display/Kconfig.mcux_dcnano_lcdif
index af91871..6390539 100644
--- a/drivers/display/Kconfig.mcux_dcnano_lcdif
+++ b/drivers/display/Kconfig.mcux_dcnano_lcdif
@@ -12,14 +12,19 @@
if DISPLAY_MCUX_DCNANO_LCDIF
-config MCUX_DCNANO_LCDIF_DOUBLE_FRAMEBUFFER
- bool "Double framebuffer"
+config MCUX_DCNANO_LCDIF_FB_NUM
+ int "Framebuffers to allocate in driver"
+ default 1
+ range 0 2
help
- Enable dual framebuffer for LCDIF peripheral. Two framebuffers
- will be allocated, and switched between for each frame.
- Note that for partial display updates, the prior framebuffer must
- be copied into the next one. This can have significant performance
- impact.
+ Number of framebuffers to allocate in DCNANO driver. Driver allocated
+ framebuffers are required to support partial display updates.
+ The driver has been validated to support 0 through 2 framebuffers.
+ Note that hardware will likely perform best if zero driver
+ framebuffers are allocated by the driver, and the application
+ implements double framebuffering by always calling display_write with
+ a buffer equal in size to the connected panel.
+
config MCUX_DCNANO_LCDIF_MAINTAIN_CACHE
bool "Maintain cache coherency"
diff --git a/drivers/display/display_mcux_dcnano_lcdif.c b/drivers/display/display_mcux_dcnano_lcdif.c
index fea80a4..7b4371a 100644
--- a/drivers/display/display_mcux_dcnano_lcdif.c
+++ b/drivers/display/display_mcux_dcnano_lcdif.c
@@ -20,12 +20,6 @@
LOG_MODULE_REGISTER(display_mcux_dcnano_lcdif, CONFIG_DISPLAY_LOG_LEVEL);
-#ifdef CONFIG_MCUX_DCNANO_LCDIF_DOUBLE_FRAMEBUFFER
-#define MCUX_DCNANO_LCDIF_FB_NUM 2
-#else
-#define MCUX_DCNANO_LCDIF_FB_NUM 1
-#endif
-
struct mcux_dcnano_lcdif_config {
LCDIF_Type *base;
void (*irq_config_func)(const struct device *dev);
@@ -38,11 +32,14 @@
};
struct mcux_dcnano_lcdif_data {
- uint8_t *fb[MCUX_DCNANO_LCDIF_FB_NUM];
- uint8_t fb_idx;
+ /* Pointer to active framebuffer */
+ const uint8_t *active_fb;
+ uint8_t *fb[CONFIG_MCUX_DCNANO_LCDIF_FB_NUM];
lcdif_fb_config_t fb_config;
uint8_t pixel_bytes;
struct k_sem sem;
+ /* Tracks index of next active driver framebuffer */
+ uint8_t next_idx;
};
static int mcux_dcnano_lcdif_write(const struct device *dev, const uint16_t x,
@@ -52,7 +49,6 @@
{
const struct mcux_dcnano_lcdif_config *config = dev->config;
struct mcux_dcnano_lcdif_data *data = dev->data;
- uint8_t next_fb_idx = (data->fb_idx + 1) % MCUX_DCNANO_LCDIF_FB_NUM;
uint32_t h_idx;
const uint8_t *src;
uint8_t *dst;
@@ -62,49 +58,64 @@
LOG_DBG("W=%d, H=%d @%d,%d", desc->width, desc->height, x, y);
-#ifdef CONFIG_MCUX_DCNANO_LCDIF_DOUBLE_FRAMEBUFFER
- /* If display write is partial, copy current framebuffer to
- * queued one. Note- this has a significant performance
- * impact, especially when using external RAM.
- */
- if ((x != 0) ||
- (y != 0) ||
- (desc->height != config->dpi_config.panelHeight) ||
- (desc->width != config->dpi_config.panelWidth)) {
- memcpy(data->fb[next_fb_idx], data->fb[data->fb_idx],
- config->fb_bytes);
- }
-#endif
+ if ((x == 0) && (y == 0) &&
+ (desc->width == config->dpi_config.panelWidth) &&
+ (desc->height == config->dpi_config.panelHeight) &&
+ (desc->pitch == desc->width)) {
+ /* We can use the display buffer directly, without copying */
+ LOG_DBG("Setting FB from %p->%p",
+ (void *)data->active_fb, (void *)buf);
+ data->active_fb = buf;
+ } else {
+ /* We must use partial framebuffer copy */
+ if (CONFIG_MCUX_DCNANO_LCDIF_FB_NUM == 0) {
+ LOG_ERR("Partial display refresh requires driver framebuffers");
+ return -ENOTSUP;
+ } else if (data->active_fb != data->fb[data->next_idx]) {
+ /*
+ * Copy the entirety of the current framebuffer to new
+ * buffer, since we are changing the active buffer address
+ */
+ src = data->active_fb;
+ dst = data->fb[data->next_idx];
+ memcpy(dst, src, config->fb_bytes);
+ }
+ /* Write the display update to the active framebuffer */
+ src = buf;
+ dst = data->fb[data->next_idx];
+ dst += data->pixel_bytes * (y * config->dpi_config.panelWidth + x);
-
- src = buf;
- dst = data->fb[next_fb_idx];
- dst += data->pixel_bytes * ((y * config->dpi_config.panelWidth) + x);
-
- for (h_idx = 0; h_idx < desc->height; h_idx++) {
- memcpy(dst, src, data->pixel_bytes * desc->width);
- src += data->pixel_bytes * desc->pitch;
- dst += data->pixel_bytes * config->dpi_config.panelWidth;
+ for (h_idx = 0; h_idx < desc->height; h_idx++) {
+ memcpy(dst, src, data->pixel_bytes * desc->width);
+ src += data->pixel_bytes * desc->pitch;
+ dst += data->pixel_bytes * config->dpi_config.panelWidth;
+ }
+ LOG_DBG("Setting FB from %p->%p", (void *) data->active_fb,
+ (void *) data->fb[data->next_idx]);
+ /* Set new active framebuffer */
+ data->active_fb = data->fb[data->next_idx];
}
#if defined(CONFIG_HAS_MCUX_CACHE) && defined(CONFIG_MCUX_DCNANO_LCDIF_MAINTAIN_CACHE)
- CACHE64_InvalidateCacheByRange((uint32_t) data->fb[next_fb_idx],
+ CACHE64_CleanCacheByRange((uint32_t) data->active_fb,
config->fb_bytes);
#endif
-
- /* Wait for framebuffer completion before writing */
- k_sem_take(&data->sem, K_FOREVER);
+ k_sem_reset(&data->sem);
/* Set new framebuffer */
LCDIF_SetFrameBufferStride(config->base, 0,
config->dpi_config.panelWidth * data->pixel_bytes);
LCDIF_SetFrameBufferAddr(config->base, 0,
- (uint32_t)data->fb[next_fb_idx]);
+ (uint32_t)data->active_fb);
LCDIF_SetFrameBufferConfig(config->base, 0, &data->fb_config);
- /* Update current framebuffer IDX */
- data->fb_idx = next_fb_idx;
+#if CONFIG_MCUX_DCNANO_LCDIF_FB_NUM != 0
+ /* Update index of active framebuffer */
+ data->next_idx = (data->next_idx + 1) % CONFIG_MCUX_DCNANO_LCDIF_FB_NUM;
+#endif
+ /* Wait for frame to complete */
+ k_sem_take(&data->sem, K_FOREVER);
return 0;
}
@@ -139,13 +150,9 @@
static void *mcux_dcnano_lcdif_get_framebuffer(const struct device *dev)
{
- const struct mcux_dcnano_lcdif_config *config = dev->config;
+ struct mcux_dcnano_lcdif_data *data = dev->data;
- if (IS_ENABLED(CONFIG_MCUX_DCNANO_LCDIF_DOUBLE_FRAMEBUFFER)) {
- return NULL; /* Direct framebuffer access not supported */
- } else {
- return config->fb_ptr;
- }
+ return (void *)data->active_fb;
}
static int mcux_dcnano_lcdif_display_blanking_off(const struct device *dev)
@@ -224,16 +231,17 @@
LCDIF_EnableInterrupts(config->base, kLCDIF_Display0FrameDoneInterrupt);
config->irq_config_func(dev);
- data->fb[0] = config->fb_ptr;
-#ifdef CONFIG_MCUX_DCNANO_LCDIF_DOUBLE_FRAMEBUFFER
- data->fb[1] = config->fb_ptr + config->fb_bytes;
-#endif
+ for (int i = 0; i < CONFIG_MCUX_DCNANO_LCDIF_FB_NUM; i++) {
+ /* Record pointers to each driver framebuffer */
+ data->fb[i] = config->fb_ptr + (config->fb_bytes * i);
+ }
+ data->active_fb = config->fb_ptr;
k_sem_init(&data->sem, 1, 1);
#ifdef CONFIG_MCUX_DCNANO_LCDIF_EXTERNAL_FB_MEM
/* Clear external memory, as it is uninitialized */
- memset(config->fb_ptr, 0, config->fb_bytes * MCUX_DCNANO_LCDIF_FB_NUM);
+ memset(config->fb_ptr, 0, config->fb_bytes * CONFIG_MCUX_DCNANO_LCDIF_FB_NUM);
#endif
return 0;
@@ -266,9 +274,9 @@
mcux_dcnano_lcdif_frame_buffer_##n[DT_INST_PROP(n, width) * \
DT_INST_PROP(n, height) * \
MCUX_DCNANO_LCDIF_PIXEL_BYTES(n) * \
- MCUX_DCNANO_LCDIF_FB_NUM]
+ CONFIG_MCUX_DCNANO_LCDIF_FB_NUM]
#define MCUX_DCNANO_LCDIF_FB_SIZE(n) \
- sizeof(mcux_dcnano_lcdif_frame_buffer_##n) / MCUX_DCNANO_LCDIF_FB_NUM
+ sizeof(mcux_dcnano_lcdif_frame_buffer_##n) / CONFIG_MCUX_DCNANO_LCDIF_FB_NUM
#define MCUX_DCNANO_LCDIF_FRAMEBUFFER(n) mcux_dcnano_lcdif_frame_buffer_##n
#endif
@@ -289,6 +297,7 @@
.enableGamma = false, \
.format = DT_INST_PROP(n, pixel_format), \
}, \
+ .next_idx = 0, \
.pixel_bytes = MCUX_DCNANO_LCDIF_PIXEL_BYTES(n), \
}; \
struct mcux_dcnano_lcdif_config mcux_dcnano_lcdif_config_##n = { \
