diff options
| -rw-r--r-- | drivers/video/mxsfb.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/drivers/video/mxsfb.c b/drivers/video/mxsfb.c index c55cb44ff..03b0f88ac 100644 --- a/drivers/video/mxsfb.c +++ b/drivers/video/mxsfb.c @@ -15,11 +15,14 @@ #include <asm/errno.h> #include <asm/io.h> +#include <asm/imx-common/dma.h> + #include "videomodes.h" #define PS2KHZ(ps) (1000000000UL / (ps)) static GraphicDevice panel; +struct mxs_dma_desc desc; /** * mxsfb_system_setup() - Fine-tune LCDIF configuration @@ -194,5 +197,28 @@ void *video_hw_init(void) /* Start framebuffer */ mxs_lcd_init(&panel, &mode, bpp); +#ifdef CONFIG_VIDEO_MXS_MODE_SYSTEM + /* + * If the LCD runs in system mode, the LCD refresh has to be triggered + * manually by setting the RUN bit in HW_LCDIF_CTRL register. To avoid + * having to set this bit manually after every single change in the + * framebuffer memory, we set up specially crafted circular DMA, which + * sets the RUN bit, then waits until it gets cleared and repeats this + * infinitelly. This way, we get smooth continuous updates of the LCD. + */ + struct mxs_lcdif_regs *regs = (struct mxs_lcdif_regs *)MXS_LCDIF_BASE; + + memset(&desc, 0, sizeof(struct mxs_dma_desc)); + desc.address = (dma_addr_t)&desc; + desc.cmd.data = MXS_DMA_DESC_COMMAND_NO_DMAXFER | MXS_DMA_DESC_CHAIN | + MXS_DMA_DESC_WAIT4END | + (1 << MXS_DMA_DESC_PIO_WORDS_OFFSET); + desc.cmd.pio_words[0] = readl(®s->hw_lcdif_ctrl) | LCDIF_CTRL_RUN; + desc.cmd.next = (uint32_t)&desc.cmd; + + /* Execute the DMA chain. */ + mxs_dma_circ_start(MXS_DMA_CHANNEL_AHB_APBH_LCDIF, &desc); +#endif + return (void *)&panel; } |