Re: [PATCH 6/6] s3c-fb: Add wait for VSYNC ioctl

[Ben Dooks <ben-linux@fluff.org>]

On Mon, May 31, 2010 at 11:08:55AM +0200, Pawel Osciak wrote:
> Add VSYNC interrupt support and an ioctl that allows waiting for it.
> Interrupts are turned on only when needed.
> 
> Signed-off-by: Pawel Osciak <p.osciak@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> ---
>  arch/arm/plat-samsung/include/plat/regs-fb.h |    1 +
>  drivers/video/s3c-fb.c                       |  171 +++++++++++++++++++++++++-
>  2 files changed, 171 insertions(+), 1 deletions(-)
> 
> diff --git a/arch/arm/plat-samsung/include/plat/regs-fb.h b/arch/arm/plat-samsung/include/plat/regs-fb.h
> index f454e32..5bcdd09 100644
> --- a/arch/arm/plat-samsung/include/plat/regs-fb.h
> +++ b/arch/arm/plat-samsung/include/plat/regs-fb.h
> @@ -298,6 +298,7 @@
>  #define VIDINTCON0_FRAMESEL0_FRONTPORCH		(0x3 << 15)
>  
>  #define VIDINTCON0_FRAMESEL1			(1 << 13)
> +#define VIDINTCON0_FRAMESEL1_MASK		(0x3 << 13)
>  #define VIDINTCON0_FRAMESEL1_NONE		(0x0 << 13)
>  #define VIDINTCON0_FRAMESEL1_BACKPORCH		(0x1 << 13)
>  #define VIDINTCON0_FRAMESEL1_VSYNC		(0x2 << 13)
> diff --git a/drivers/video/s3c-fb.c b/drivers/video/s3c-fb.c
> index 4f3680d..0dfa8b0 100644
> --- a/drivers/video/s3c-fb.c
> +++ b/drivers/video/s3c-fb.c
> @@ -21,6 +21,8 @@
>  #include <linux/clk.h>
>  #include <linux/fb.h>
>  #include <linux/io.h>
> +#include <linux/uaccess.h>
> +#include <linux/interrupt.h>
>  
>  #include <mach/map.h>
>  #include <plat/regs-fb-v4.h>
> @@ -48,6 +50,15 @@
>  	__raw_writel(v, r); } while(0)
>  #endif /* FB_S3C_DEBUG_REGWRITE */
>  
> +/* irq_flags bits */
> +#define S3C_FB_VSYNC_IRQ_EN	0
> +
> +#ifndef FBIO_WAITFORVSYNC
> +#define FBIO_WAITFORVSYNC _IOW('F', 0x20, __u32)
> +#endif
> +
> +#define VSYNC_TIMEOUT_MSEC 50

why are you testign for this, surely you need t oget FBIO_WAITFORVSYNC
from a header file.

>  struct s3c_fb;
>  
>  #define VALID_BPP(x) (1 << ((x) - 1))
> @@ -156,6 +167,16 @@ struct s3c_fb_win {
>  };
>  
>  /**
> + * struct s3c_fb_vsync - vsync information
> + * @wait:	a queue for processes waiting for vsync
> + * @count:	vsync interrupt count
> + */
> +struct s3c_fb_vsync {
> +	wait_queue_head_t	wait;
> +	unsigned int		count;
> +};
> +
> +/**
>   * struct s3c_fb - overall hardware state of the hardware
>   * @dev: The device that we bound to, for printing, etc.
>   * @regs_res: The resource we claimed for the IO registers.
> @@ -165,6 +186,9 @@ struct s3c_fb_win {
>   * @enabled: A bitmask of enabled hardware windows.
>   * @pdata: The platform configuration data passed with the device.
>   * @windows: The hardware windows that have been claimed.
> + * @irq_no: IRQ line number
> + * @irq_flags: irq flags
> + * @vsync_info: VSYNC-related information (count, queues...)
>   */
>  struct s3c_fb {
>  	struct device		*dev;
> @@ -177,6 +201,10 @@ struct s3c_fb {
>  
>  	struct s3c_fb_platdata	*pdata;
>  	struct s3c_fb_win	*windows[S3C_FB_MAX_WIN];
> +
> +	int			 irq_no;
> +	unsigned long		 irq_flags;
> +	struct s3c_fb_vsync	 vsync_info;
>  };
>  
>  /**
> @@ -801,6 +829,124 @@ static int s3c_fb_pan_display(struct fb_var_screeninfo *var,
>  	return 0;
>  }
>  
> +/**
> + * s3c_fb_enable_irq() - enable framebuffer interrupts
> + * @sfb: main hardware state
> + */
> +static void s3c_fb_enable_irq(struct s3c_fb *sfb)
> +{
> +	void __iomem *regs = sfb->regs;
> +	u32 irq_ctrl_reg;
> +
> +	if (!test_and_set_bit(S3C_FB_VSYNC_IRQ_EN, &sfb->irq_flags)) {
> +		/* IRQ disabled, enable it */
> +		irq_ctrl_reg = readl(regs + VIDINTCON0);
> +
> +		irq_ctrl_reg |= VIDINTCON0_INT_ENABLE;
> +		irq_ctrl_reg |= VIDINTCON0_INT_FRAME;
> +
> +		irq_ctrl_reg &= ~VIDINTCON0_FRAMESEL0_MASK;
> +		irq_ctrl_reg |= VIDINTCON0_FRAMESEL0_VSYNC;
> +		irq_ctrl_reg &= ~VIDINTCON0_FRAMESEL1_MASK;
> +		irq_ctrl_reg |= VIDINTCON0_FRAMESEL1_NONE;
> +
> +		writel(irq_ctrl_reg, regs + VIDINTCON0);
> +	}
> +}
> +
> +/**
> + * s3c_fb_disable_irq() - disable framebuffer interrupts
> + * @sfb: main hardware state
> + */
> +static void s3c_fb_disable_irq(struct s3c_fb *sfb)
> +{
> +	void __iomem *regs = sfb->regs;
> +	u32 irq_ctrl_reg;
> +
> +	if (test_and_clear_bit(S3C_FB_VSYNC_IRQ_EN, &sfb->irq_flags)) {
> +		/* IRQ enabled, disable it */
> +		irq_ctrl_reg = readl(regs + VIDINTCON0);
> +
> +		irq_ctrl_reg &= ~VIDINTCON0_INT_FRAME;
> +		irq_ctrl_reg &= ~VIDINTCON0_INT_ENABLE;
> +
> +		writel(irq_ctrl_reg, regs + VIDINTCON0);
> +	}
> +}
> +
> +static irqreturn_t s3c_fb_irq(int irq, void *dev_id)
> +{
> +	struct s3c_fb *sfb = dev_id;
> +	void __iomem  *regs = sfb->regs;
> +	u32 irq_sts_reg;
> +
> +	irq_sts_reg = readl(regs + VIDINTCON1);
> +
> +	if (irq_sts_reg & VIDINTCON1_INT_FRAME) {
> +
> +		/* VSYNC interrupt, accept it */
> +		writel(VIDINTCON1_INT_FRAME, regs + VIDINTCON1);
> +
> +		sfb->vsync_info.count++;
> +		wake_up_interruptible(&sfb->vsync_info.wait);
> +	}
> +
> +	/* We only support waiting for VSYNC for now, so it's safe
> +	 * to always disable irqs here.
> +	 */
> +	s3c_fb_disable_irq(sfb);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +/**
> + * s3c_fb_wait_for_vsync() - sleep until next VSYNC interrupt or timeout
> + * @sfb: main hardware state
> + * @crtc: head index.
> + */
> +static int s3c_fb_wait_for_vsync(struct s3c_fb *sfb, u32 crtc)
> +{
> +	unsigned long count;
> +	int ret;
> +
> +	if (crtc != 0)
> +		return -ENODEV;
> +
> +	s3c_fb_enable_irq(sfb);
> +	count = sfb->vsync_info.count;
> +	ret = wait_event_interruptible_timeout(sfb->vsync_info.wait,
> +				       count != sfb->vsync_info.count,
> +				       msecs_to_jiffies(VSYNC_TIMEOUT_MSEC));
> +	if (ret = 0)
> +		return -ETIMEDOUT;
> +
> +	return 0;
> +}
> +
> +static int s3c_fb_ioctl(struct fb_info *info, unsigned int cmd,
> +			unsigned long arg)
> +{
> +	struct s3c_fb_win *win = info->par;
> +	struct s3c_fb *sfb = win->parent;
> +	int ret;
> +	u32 crtc;
> +
> +	switch (cmd) {
> +	case FBIO_WAITFORVSYNC:
> +		if (get_user(crtc, (u32 __user *)arg)) {
> +			ret = -EFAULT;
> +			break;
> +		}
> +
> +		ret = s3c_fb_wait_for_vsync(sfb, crtc);
> +		break;
> +	default:
> +		ret = -ENOTTY;
> +	}
> +
> +	return ret;
> +}
> +
>  static struct fb_ops s3c_fb_ops = {
>  	.owner		= THIS_MODULE,
>  	.fb_check_var	= s3c_fb_check_var,
> @@ -811,6 +957,7 @@ static struct fb_ops s3c_fb_ops = {
>  	.fb_copyarea	= cfb_copyarea,
>  	.fb_imageblit	= cfb_imageblit,
>  	.fb_pan_display	= s3c_fb_pan_display,
> +	.fb_ioctl	= s3c_fb_ioctl,
>  };
>  
>  /**
> @@ -917,6 +1064,8 @@ static int __devinit s3c_fb_probe_win(struct s3c_fb *sfb, unsigned int win_no,
>  
>  	dev_dbg(sfb->dev, "probing window %d, variant %p\n", win_no, variant);
>  
> +	init_waitqueue_head(&sfb->vsync_info.wait);
> +
>  	palette_size = variant->palette_sz * 4;
>  
>  	fbinfo = framebuffer_alloc(sizeof(struct s3c_fb_win) +
> @@ -1096,6 +1245,20 @@ static int __devinit s3c_fb_probe(struct platform_device *pdev)
>  		goto err_req_region;
>  	}
>  
> +	res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
> +	if (!res) {
> +		dev_err(dev, "failed to acquire irq resource\n");
> +		ret = -ENOENT;
> +		goto err_ioremap;
> +	}
> +	sfb->irq_no = res->start;
> +	ret = request_irq(sfb->irq_no, s3c_fb_irq,
> +			  0, "s3c_fb", sfb);
> +	if (ret) {
> +		dev_err(dev, "irq request failed\n");
> +		goto err_ioremap;
> +	}
> +
>  	dev_dbg(dev, "got resources (regs %p), probing windows\n", sfb->regs);
>  
>  	/* setup gpio and output polarity controls */
> @@ -1130,7 +1293,7 @@ static int __devinit s3c_fb_probe(struct platform_device *pdev)
>  			dev_err(dev, "failed to create window %d\n", win);
>  			for (; win >= 0; win--)
>  				s3c_fb_release_win(sfb, sfb->windows[win]);
> -			goto err_ioremap;
> +			goto err_irq;
>  		}
>  	}
>  
> @@ -1138,6 +1301,9 @@ static int __devinit s3c_fb_probe(struct platform_device *pdev)
>  
>  	return 0;
>  
> +err_irq:
> +	free_irq(sfb->irq_no, sfb);
> +
>  err_ioremap:
>  	iounmap(sfb->regs);
>  
> @@ -1170,6 +1336,8 @@ static int __devexit s3c_fb_remove(struct platform_device *pdev)
>  		if (sfb->windows[win])
>  			s3c_fb_release_win(sfb, sfb->windows[win]);
>  
> +	free_irq(sfb->irq_no, sfb);
> +
>  	iounmap(sfb->regs);
>  
>  	clk_disable(sfb->bus_clk);
> @@ -1370,6 +1538,7 @@ static struct s3c_fb_driverdata s3c_fb_data_s5pv210 __devinitdata = {
>  			[3] = 0x3000,
>  			[4] = 0x3400,
>  		},
> +
>  	},
>  	.win[0]	= &s3c_fb_data_64xx_wins[0],
>  	.win[1]	= &s3c_fb_data_64xx_wins[1],
> -- 
> 1.7.0.4
> 

-- 
-- 
Ben

Q:      What's a light-year?
A:      One-third less calories than a regular year.