Re: [PATCH v3 1/4] drm/rockchip: vop: export line flag function
From: Yakir Yang
Date: Thu Jul 07 2016 - 22:30:43 EST
Sean,
On 07/01/2016 11:32 PM, Sean Paul wrote:
On Fri, Jul 1, 2016 at 11:30 AM, Sean Paul <seanpaul@xxxxxxxxxxxx> wrote:
On Fri, Jul 1, 2016 at 5:19 AM, Yakir Yang <ykk@xxxxxxxxxxxxxx> wrote:
VOP have integrated a hardware counter which indicate the exact display
line that vop is scanning. And if we're interested in a specific line,
we can set the line number to vop line_flag register, and then vop would
generate a line_flag interrupt for it.
For example eDP PSR function is interested in the vertical blanking
period, then driver could set the line number to zero.
This patch have exported a symbol that allow other driver to listen the
line flag event with given timeout limit:
- rockchip_drm_wait_line_flag()
Signed-off-by: Yakir Yang <ykk@xxxxxxxxxxxxxx>
---
Changes in v3:
- Export the 'rockchip_drm_wait_line_flag' symbol, and document it.
- Add 'line_flag_num_0' for RK3288/RK3036
- Remove the notify for waiting line_flag event (Daniel)
Changes in v2:
- Introduce in v2, split VOP line flag changes out
drivers/gpu/drm/rockchip/rockchip_drm_drv.h | 3 +
drivers/gpu/drm/rockchip/rockchip_drm_vop.c | 103 ++++++++++++++++++++++++++++
drivers/gpu/drm/rockchip/rockchip_drm_vop.h | 3 +
drivers/gpu/drm/rockchip/rockchip_vop_reg.c | 4 ++
4 files changed, 113 insertions(+)
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.h b/drivers/gpu/drm/rockchip/rockchip_drm_drv.h
index ea39329..239b830 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.h
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.h
@@ -70,4 +70,7 @@ int rockchip_drm_dma_attach_device(struct drm_device *drm_dev,
struct device *dev);
void rockchip_drm_dma_detach_device(struct drm_device *drm_dev,
struct device *dev);
+int rockchip_drm_wait_line_flag(struct drm_crtc *crtc, unsigned int line_num,
+ unsigned int mstimeout);
+
#endif /* _ROCKCHIP_DRM_DRV_H_ */
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
index c8a62a8..cd3cac5 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.c
@@ -121,6 +121,8 @@ struct vop {
/* protected by dev->event_lock */
struct drm_pending_vblank_event *event;
+ struct completion line_flag_completion;
+
const struct vop_data *data;
uint32_t *regsbak;
@@ -431,6 +433,59 @@ static void vop_dsp_hold_valid_irq_disable(struct vop *vop)
spin_unlock_irqrestore(&vop->irq_lock, flags);
}
+/*
+ * (1) each frame starts at the start of the Vsync pulse which is signaled by
+ * the "FRAME_SYNC" interrupt.
+ * (2) the active data region of each frame ends at dsp_vact_end
+ * (3) we should program this same number (dsp_vact_end) into dsp_line_frag_num,
+ * to get "LINE_FLAG" interrupt at the end of the active on screen data.
+ *
+ * VOP_INTR_CTRL0.dsp_line_frag_num = VOP_DSP_VACT_ST_END.dsp_vact_end
+ * Interrupts
+ * LINE_FLAG -------------------------------+
+ * FRAME_SYNC ----+ |
+ * | |
+ * v v
+ * | Vsync | Vbp | Vactive | Vfp |
+ * ^ ^ ^ ^
+ * | | | |
+ * | | | |
+ * dsp_vs_end ------------+ | | | VOP_DSP_VTOTAL_VS_END
+ * dsp_vact_start --------------+ | | VOP_DSP_VACT_ST_END
+ * dsp_vact_end ----------------------------+ | VOP_DSP_VACT_ST_END
+ * dsp_total -------------------------------------+ VOP_DSP_VTOTAL_VS_END
+ */
+
+static void vop_line_flag_irq_enable(struct vop *vop, int line_num)
+{
+ unsigned long flags;
+
+ if (WARN_ON(!vop->is_enabled))
+ return;
+
+ spin_lock_irqsave(&vop->irq_lock, flags);
+
+ VOP_CTRL_SET(vop, line_flag_num_0, line_num);
+ VOP_INTR_SET_TYPE(vop, enable, LINE_FLAG_INTR, 1);
+ vop_cfg_done(vop);
+
+ spin_unlock_irqrestore(&vop->irq_lock, flags);
+}
+
+static void vop_line_flag_irq_disable(struct vop *vop)
+{
+ unsigned long flags;
+
+ if (WARN_ON(!vop->is_enabled))
+ return;
+
+ spin_lock_irqsave(&vop->irq_lock, flags);
+
+ VOP_INTR_SET_TYPE(vop, enable, LINE_FLAG_INTR, 0);
+
+ spin_unlock_irqrestore(&vop->irq_lock, flags);
+}
+
static void vop_enable(struct drm_crtc *crtc)
{
struct vop *vop = to_vop(crtc);
@@ -1157,6 +1212,13 @@ static irqreturn_t vop_isr(int irq, void *data)
ret = IRQ_HANDLED;
}
+ if (active_irqs & LINE_FLAG_INTR) {
+ if (!completion_done(&vop->line_flag_completion))
+ complete(&vop->line_flag_completion);
I think there's potential to miss flags here if the timing is just
right because the completion_done and complete are not atomic wrt the
wait_line_flag function. I think you need some locking around the
completion operations to ensure they're properly sequenced.
FWIW, if you're reinitializing the completion every time in
drm_wait_line_flag, you should be able to just call complete (or
complete_all) without checking if there are any waiters.
I should add, if you just call complete/complete_all() here, you
shouldn't need to add locking (assuming only one waiter).
Yes, only one waiter.
+ active_irqs &= ~LINE_FLAG_INTR;
+ ret = IRQ_HANDLED;
+ }
+
if (active_irqs & FS_INTR) {
drm_crtc_handle_vblank(crtc);
vop_handle_vblank(vop);
@@ -1255,6 +1317,7 @@ static int vop_create_crtc(struct vop *vop)
init_completion(&vop->dsp_hold_completion);
init_completion(&vop->wait_update_complete);
+ init_completion(&vop->line_flag_completion);
crtc->port = port;
rockchip_register_crtc_funcs(crtc, &private_crtc_funcs);
@@ -1411,6 +1474,46 @@ static void vop_win_init(struct vop *vop)
}
}
+/**
+ * rockchip_drm_wait_line_flag - acqiure the give line flag event
+ * @crtc: CRTC to enable line flag
+ * @line_num: interested line number
+ * @mstimeout: millisecond for timeout
+ *
+ * Driver would hold here until the interested line flag interrupt have
+ * happened or timeout to wait.
+ *
+ * Returns:
+ * Zero on success, negative errno on failure.
+ */
+int rockchip_drm_wait_line_flag(struct drm_crtc *crtc, unsigned int line_num,
+ unsigned int mstimeout)
+{
+ struct vop *vop = to_vop(crtc);
+ unsigned long jiffies_left;
+
+ if (!crtc || !vop->is_enabled)
+ return -ENODEV;
+
+ if (line_num > crtc->mode.vtotal || mstimeout <= 0)
+ return -EINVAL;
+
+ reinit_completion(&vop->line_flag_completion);
+ vop_line_flag_irq_enable(vop, line_num);
+
This will only work for one waiter per vop. Is it worth enforcing this
explicitly to avoid weird behavior when there are more than one?
Yes, you're right, need to avoid the weird behavior here.
+ jiffies_left = wait_for_completion_timeout(&vop->line_flag_completion,
+ msecs_to_jiffies(mstimeout));
+ vop_line_flag_irq_disable(vop);
+
+ if (jiffies_left == 0) {
+ dev_err(vop->dev, "Timeout waiting for IRQ\n");
+ return -ETIMEDOUT;
+ }
+
+ return 0;
+}
+EXPORT_SYMBOL(rockchip_drm_wait_line_flag);
+
static int vop_bind(struct device *dev, struct device *master, void *data)
{
struct platform_device *pdev = to_platform_device(dev);
diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop.h b/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
index ff4f52e..34fcd03 100644
--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop.h
@@ -61,6 +61,9 @@ struct vop_ctrl {
struct vop_reg hpost_st_end;
struct vop_reg vpost_st_end;
+ struct vop_reg line_flag_num_0;
+ struct vop_reg line_flag_num_1;
+
nit: you could make this an array:
struct vop_reg line_flag_num[2];
Done,
struct vop_reg cfg_done;
};
diff --git a/drivers/gpu/drm/rockchip/rockchip_vop_reg.c b/drivers/gpu/drm/rockchip/rockchip_vop_reg.c
index 6f42e56..e9211c9 100644
--- a/drivers/gpu/drm/rockchip/rockchip_vop_reg.c
+++ b/drivers/gpu/drm/rockchip/rockchip_vop_reg.c
@@ -122,6 +122,7 @@ static const struct vop_ctrl rk3036_ctrl_data = {
.hact_st_end = VOP_REG(RK3036_DSP_HACT_ST_END, 0x1fff1fff, 0),
.vtotal_pw = VOP_REG(RK3036_DSP_VTOTAL_VS_END, 0x1fff1fff, 0),
.vact_st_end = VOP_REG(RK3036_DSP_VACT_ST_END, 0x1fff1fff, 0),
+ .line_flag_num_0 = VOP_REG(RK3036_INT_STATUS, 0xfff, 12),
.cfg_done = VOP_REG(RK3036_REG_CFG_DONE, 0x1, 0),
};
@@ -221,6 +222,7 @@ static const struct vop_ctrl rk3288_ctrl_data = {
.vact_st_end = VOP_REG(RK3288_DSP_VACT_ST_END, 0x1fff1fff, 0),
.hpost_st_end = VOP_REG(RK3288_POST_DSP_HACT_INFO, 0x1fff1fff, 0),
.vpost_st_end = VOP_REG(RK3288_POST_DSP_VACT_INFO, 0x1fff1fff, 0),
+ .line_flag_num_0 = VOP_REG(RK3288_INTR_CTRL0, 0x1fff, 12),
.cfg_done = VOP_REG(RK3288_REG_CFG_DONE, 0x1, 0),
};
@@ -299,6 +301,8 @@ static const struct vop_ctrl rk3399_ctrl_data = {
.vact_st_end = VOP_REG(RK3399_DSP_VACT_ST_END, 0x1fff1fff, 0),
.hpost_st_end = VOP_REG(RK3399_POST_DSP_HACT_INFO, 0x1fff1fff, 0),
.vpost_st_end = VOP_REG(RK3399_POST_DSP_VACT_INFO, 0x1fff1fff, 0),
+ .line_flag_num_0 = VOP_REG(RK3399_LINE_FLAG, 0xffff, 0),
+ .line_flag_num_1 = VOP_REG(RK3399_LINE_FLAG, 0xffff, 16),
.cfg_done = VOP_REG_MASK(RK3399_REG_CFG_DONE, 0x1, 0),
};
--
1.9.1