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media: bcm2835: unicam: Set VPU min clock freq to 250Mhz.

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When streaming with Unicam, the VPU must have a clock frequency of at
least 250Mhz.  Otherwise, the input fifos could overrun, causing
image corruption.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
This commit is contained in:
Naushir Patuck
2020-05-11 13:02:22 +01:00
committed by Dom Cobley
parent 62d5cd41ee
commit cbc60ec97d
1 changed files with 44 additions and 5 deletions
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49
drivers/media/platform/bcm2835/bcm2835-unicam.c
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@@ -90,6 +90,11 @@ MODULE_PARM_DESC(debug, "Debug level 0-3");
#define unicam_err(dev, fmt, arg...) \
v4l2_err(&(dev)->v4l2_dev, fmt, ##arg)
/*
* Unicam must request a minimum of 250Mhz from the VPU clock.
* Otherwise the input FIFOs overrun and cause image corruption.
*/
#define MIN_VPU_CLOCK_RATE (250 * 1000 * 1000)
/*
* To protect against a dodgy sensor driver never returning an error from
* enum_mbus_code, set a maximum index value to be used.
@@ -419,8 +424,10 @@ struct unicam_device {
void __iomem *base;
/* clock gating base address */
void __iomem *clk_gate_base;
/* clock handle */
/* lp clock handle */
struct clk *clock;
/* vpu clock handle */
struct clk *vpu_clock;
/* V4l2 device */
struct v4l2_device v4l2_dev;
struct media_device mdev;
@@ -1680,16 +1687,28 @@ static int unicam_start_streaming(struct vb2_queue *vq, unsigned int count)
unicam_dbg(1, dev, "Running with %u data lanes\n",
dev->active_data_lanes);
ret = clk_set_min_rate(dev->vpu_clock, MIN_VPU_CLOCK_RATE);
if (ret) {
unicam_err(dev, "failed to set up VPU clock\n");
goto err_pm_put;
}
ret = clk_prepare_enable(dev->vpu_clock);
if (ret) {
unicam_err(dev, "Failed to enable VPU clock: %d\n", ret);
goto err_pm_put;
}
ret = clk_set_rate(dev->clock, 100 * 1000 * 1000);
if (ret) {
unicam_err(dev, "failed to set up clock\n");
goto err_pm_put;
unicam_err(dev, "failed to set up CSI clock\n");
goto err_vpu_clock;
}
ret = clk_prepare_enable(dev->clock);
if (ret) {
unicam_err(dev, "Failed to enable CSI clock: %d\n", ret);
goto err_pm_put;
goto err_vpu_clock;
}
for (i = 0; i < ARRAY_SIZE(dev->node); i++) {
@@ -1723,6 +1742,11 @@ static int unicam_start_streaming(struct vb2_queue *vq, unsigned int count)
err_disable_unicam:
unicam_disable(dev);
clk_disable_unprepare(dev->clock);
err_vpu_clock:
ret = clk_set_min_rate(dev->vpu_clock, 0);
if (ret)
unicam_err(dev, "failed to reset the VPU clock\n");
clk_disable_unprepare(dev->vpu_clock);
err_pm_put:
unicam_runtime_put(dev);
err_streaming:
@@ -1740,6 +1764,8 @@ static void unicam_stop_streaming(struct vb2_queue *vq)
node->streaming = false;
if (node->pad_id == IMAGE_PAD) {
int ret;
/*
* Stop streaming the sensor and disable the peripheral.
* We cannot continue streaming embedded data with the
@@ -1749,6 +1775,12 @@ static void unicam_stop_streaming(struct vb2_queue *vq)
unicam_err(dev, "stream off failed in subdev\n");
unicam_disable(dev);
ret = clk_set_min_rate(dev->vpu_clock, 0);
if (ret)
unicam_err(dev, "failed to reset the min VPU clock\n");
clk_disable_unprepare(dev->vpu_clock);
clk_disable_unprepare(dev->clock);
unicam_runtime_put(dev);
@@ -2752,11 +2784,18 @@ static int unicam_probe(struct platform_device *pdev)
unicam->clock = devm_clk_get(&pdev->dev, "lp");
if (IS_ERR(unicam->clock)) {
unicam_err(unicam, "Failed to get clock\n");
unicam_err(unicam, "Failed to get lp clock\n");
ret = PTR_ERR(unicam->clock);
goto err_unicam_put;
}
unicam->vpu_clock = devm_clk_get(&pdev->dev, "vpu");
if (IS_ERR(unicam->vpu_clock)) {
unicam_err(unicam, "Failed to get vpu clock\n");
ret = PTR_ERR(unicam->vpu_clock);
goto err_unicam_put;
}
ret = platform_get_irq(pdev, 0);
if (ret <= 0) {
dev_err(&pdev->dev, "No IRQ resource\n");