s3c-fb: add wait for VSYNC ioctl

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>
Cc: InKi Dae <inki.dae@samsung.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 166 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 dbb6c0afef47..564594e89efe 100644
--- a/arch/arm/plat-samsung/include/plat/regs-fb.h
+++ b/arch/arm/plat-samsung/include/plat/regs-fb.h
@@ -300,6 +300,7 @@
 #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 de427d928f48..2e82adf9ab6d 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 +50,11 @@
         __raw_writel(v, r); } while(0)
 #endif /* FB_S3C_DEBUG_REGWRITE */
 
+/* irq_flags bits */
+#define S3C_FB_VSYNC_IRQ_EN     0
+
+#define VSYNC_TIMEOUT_MSEC 50
+
 struct s3c_fb;
 
 #define VALID_BPP(x) (1 << ((x) - 1))
@@ -156,6 +163,16 @@ 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 +182,9 @@ 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 +197,10 @@ 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;
 };
 
 /**
@@ -798,6 +822,124 @@ 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;
+
+        count = sfb->vsync_info.count;
+        s3c_fb_enable_irq(sfb);
+        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,
@@ -808,6 +950,7 @@ 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,
 };
 
 /**
@@ -914,6 +1057,8 @@ 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) +
@@ -1093,6 +1238,20 @@ 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 */
@@ -1127,7 +1286,7 @@ 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;
                 }
         }
 
@@ -1135,6 +1294,9 @@ 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);
 
@@ -1167,6 +1329,8 @@ 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);