atmel_lcdfb: FIFO underflow management (d22579b8) · Commits · 戴 / test

drivers/video/atmel_lcdfb.c

+56 −1

Original line number	Diff line number	Diff line
		@@ -379,6 +379,35 @@ static int atmel_lcdfb_check_var(struct fb_var_screeninfo *var,
		return 0;
		}

		/*
		* LCD reset sequence
		*/
		static void atmel_lcdfb_reset(struct atmel_lcdfb_info *sinfo)
		{
		might_sleep();

		/* LCD power off */
		lcdc_writel(sinfo, ATMEL_LCDC_PWRCON, sinfo->guard_time << ATMEL_LCDC_GUARDT_OFFSET);

		/* wait for the LCDC core to become idle */
		while (lcdc_readl(sinfo, ATMEL_LCDC_PWRCON) & ATMEL_LCDC_BUSY)
		msleep(10);

		/* DMA disable */
		lcdc_writel(sinfo, ATMEL_LCDC_DMACON, 0);

		/* wait for DMA engine to become idle */
		while (lcdc_readl(sinfo, ATMEL_LCDC_DMACON) & ATMEL_LCDC_DMABUSY)
		msleep(10);

		/* LCD power on */
		lcdc_writel(sinfo, ATMEL_LCDC_PWRCON,
		(sinfo->guard_time << ATMEL_LCDC_GUARDT_OFFSET) \| ATMEL_LCDC_PWR);

		/* DMA enable */
		lcdc_writel(sinfo, ATMEL_LCDC_DMACON, sinfo->default_dmacon);
		}

		/**
		* atmel_lcdfb_set_par - Alters the hardware state.
		* @info: frame buffer structure that represents a single frame buffer
		@@ -401,6 +430,8 @@ static int atmel_lcdfb_set_par(struct fb_info *info)
		unsigned long clk_value_khz;
		unsigned long bits_per_line;

		might_sleep();

		dev_dbg(info->device, "%s:\n", __func__);
		dev_dbg(info->device, " * resolution: %ux%u (%ux%u virtual)\n",
		info->var.xres, info->var.yres,
		@@ -511,6 +542,8 @@ static int atmel_lcdfb_set_par(struct fb_info *info)

		/* Disable all interrupts */
		lcdc_writel(sinfo, ATMEL_LCDC_IDR, ~0UL);
		/* Enable FIFO & DMA errors */
		lcdc_writel(sinfo, ATMEL_LCDC_IER, ATMEL_LCDC_UFLWI \| ATMEL_LCDC_OWRI \| ATMEL_LCDC_MERI);

		/* ...wait for DMA engine to become idle... */
		while (lcdc_readl(sinfo, ATMEL_LCDC_DMACON) & ATMEL_LCDC_DMABUSY)
		@@ -645,10 +678,26 @@ static irqreturn_t atmel_lcdfb_interrupt(int irq, void *dev_id)
		u32 status;

		status = lcdc_readl(sinfo, ATMEL_LCDC_ISR);
		lcdc_writel(sinfo, ATMEL_LCDC_IDR, status);
		if (status & ATMEL_LCDC_UFLWI) {
		dev_warn(info->device, "FIFO underflow %#x\n", status);
		/* reset DMA and FIFO to avoid screen shifting */
		schedule_work(&sinfo->task);
		}
		lcdc_writel(sinfo, ATMEL_LCDC_ICR, status);
		return IRQ_HANDLED;
		}

		/*
		* LCD controller task (to reset the LCD)
		*/
		static void atmel_lcdfb_task(struct work_struct *work)
		{
		struct atmel_lcdfb_info *sinfo =
		container_of(work, struct atmel_lcdfb_info, task);

		atmel_lcdfb_reset(sinfo);
		}

		static int __init atmel_lcdfb_init_fbinfo(struct atmel_lcdfb_info *sinfo)
		{
		struct fb_info *info = sinfo->info;
		@@ -824,6 +873,10 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
		goto unmap_mmio;
		}

		/* Some operations on the LCDC might sleep and
		* require a preemptible task context */
		INIT_WORK(&sinfo->task, atmel_lcdfb_task);

		ret = atmel_lcdfb_init_fbinfo(sinfo);
		if (ret < 0) {
		dev_err(dev, "init fbinfo failed: %d\n", ret);
		@@ -866,6 +919,7 @@ static int __init atmel_lcdfb_probe(struct platform_device *pdev)
		free_cmap:
		fb_dealloc_cmap(&info->cmap);
		unregister_irqs:
		cancel_work_sync(&sinfo->task);
		free_irq(sinfo->irq_base, info);
		unmap_mmio:
		exit_backlight(sinfo);
		@@ -903,6 +957,7 @@ static int __exit atmel_lcdfb_remove(struct platform_device *pdev)
		if (!sinfo)
		return 0;

		cancel_work_sync(&sinfo->task);
		exit_backlight(sinfo);
		if (sinfo->atmel_lcdfb_power_control)
		sinfo->atmel_lcdfb_power_control(0);

include/video/atmel_lcdc.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -37,6 +37,7 @@ struct atmel_lcdfb_info {
		struct fb_info *info;
		void __iomem *mmio;
		unsigned long irq_base;
		struct work_struct task;

		unsigned int guard_time;
		struct platform_device *pdev;

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