08.07.2021 17:37, Thierry Reding пишет:
> From: Thierry Reding <treding@xxxxxxxxxx>
>
> As of commit 4782c0a5dd88 ("clk: tegra: Don't deassert reset on enabling
> clocks"), module resets are no longer automatically deasserted when the
> module clock is enabled. To make sure that the gr2d module continues to
> work, we need to explicitly control the module reset.
>
> Fixes: 4782c0a5dd88 ("clk: tegra: Don't deassert reset on enabling clocks")
> Signed-off-by: Thierry Reding <treding@xxxxxxxxxx>
On which board do see this problem?
TRM says that 2d should be in reset by default, but somehow it's not a
problem on devices that use fastboot.. why would it touch the 2d reset?
> ---
> drivers/gpu/drm/tegra/gr2d.c | 33 +++++++++++++++++++++++++++++++--
> 1 file changed, 31 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/tegra/gr2d.c b/drivers/gpu/drm/tegra/gr2d.c
> index de288cba3905..ba3722f1b865 100644
> --- a/drivers/gpu/drm/tegra/gr2d.c
> +++ b/drivers/gpu/drm/tegra/gr2d.c
> @@ -4,9 +4,11 @@
> */
>
> #include <linux/clk.h>
> +#include <linux/delay.h>
> #include <linux/iommu.h>
> #include <linux/module.h>
> #include <linux/of_device.h>
> +#include <linux/reset.h>
>
> #include "drm.h"
> #include "gem.h"
> @@ -19,6 +21,7 @@ struct gr2d_soc {
> struct gr2d {
> struct tegra_drm_client client;
> struct host1x_channel *channel;
> + struct reset_control *rst;
Unused variable?
> struct clk *clk;
>
> const struct gr2d_soc *soc;
> @@ -208,6 +211,12 @@ static int gr2d_probe(struct platform_device *pdev)
> if (!syncpts)
> return -ENOMEM;
>
> + gr2d->rst = devm_reset_control_get(dev, NULL);
> + if (IS_ERR(gr2d->rst)) {
> + dev_err(dev, "cannot get reset\n");
> + return PTR_ERR(gr2d->rst);
> + }
> +
> gr2d->clk = devm_clk_get(dev, NULL);
> if (IS_ERR(gr2d->clk)) {
> dev_err(dev, "cannot get clock\n");
> @@ -220,6 +229,14 @@ static int gr2d_probe(struct platform_device *pdev)
> return err;
> }
>
> + usleep_range(2000, 4000);
> +
> + err = reset_control_deassert(gr2d->rst);
> + if (err < 0) {
> + dev_err(dev, "failed to deassert reset: %d\n", err);
> + goto disable_clk;
> + }
> +
> INIT_LIST_HEAD(&gr2d->client.base.list);
> gr2d->client.base.ops = &gr2d_client_ops;
> gr2d->client.base.dev = dev;
> @@ -234,8 +251,7 @@ static int gr2d_probe(struct platform_device *pdev)
> err = host1x_client_register(&gr2d->client.base);
> if (err < 0) {
> dev_err(dev, "failed to register host1x client: %d\n", err);
> - clk_disable_unprepare(gr2d->clk);
> - return err;
> + goto assert_rst;
> }
>
> /* initialize address register map */
> @@ -245,6 +261,13 @@ static int gr2d_probe(struct platform_device *pdev)
> platform_set_drvdata(pdev, gr2d);
>
> return 0;
> +
> +assert_rst:
> + (void)reset_control_assert(gr2d->rst);
(void)?
