On Tue, 8 Dec 2020 16:08:02 +0200
Tony Lindgren <tony@xxxxxxxxxxx> wrote:
> We have rst_map_012 used for various accelerators like dsp, ipu and iva.
> For these use cases, we have rstctrl bit 2 control the subsystem module
> reset, and have and bits 0 and 1 control the accelerator specific
> features.
>
> If the bootloader, or kexec boot, has left any accelerator specific
> reset bits deasserted, deasserting bit 2 reset will potentially enable
> an accelerator with unconfigured MMU and no firmware. And we may get
> spammed with a lot by warnings on boot with "Data Access in User mode
> during Functional access", or depending on the accelerator, the system
> can also just hang.
>
> This issue can be quite easily reproduced by setting a rst_map_012 type
> rstctrl register to 0 or 4 in the bootloader, and booting the system.
>
> Let's just assert all reset bits for rst_map_012 type resets. So far
> it looks like the other rstctrl types don't need this. If it turns out
> that the other type rstctrl bits also need reset on init, we need to
> add an instance specific reset mask for the bits to avoid resetting
> unwanted bits.
>
> Reported-by: Carl Philipp Klemm <philipp@xxxxxxxx>
> Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
> Cc: Santosh Shilimkar <ssantosh@xxxxxxxxxx>
> Cc: Suman Anna <s-anna@xxxxxx>
> Cc: Tero Kristo <t-kristo@xxxxxx>
> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> ---
> drivers/soc/ti/omap_prm.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/soc/ti/omap_prm.c b/drivers/soc/ti/omap_prm.c
> --- a/drivers/soc/ti/omap_prm.c
> +++ b/drivers/soc/ti/omap_prm.c
> @@ -860,6 +860,7 @@ static int omap_prm_reset_init(struct platform_device *pdev,
> const struct omap_rst_map *map;
> struct ti_prm_platform_data *pdata = dev_get_platdata(&pdev->dev);
> char buf[32];
> + u32 v;
>
> /*
> * Check if we have controllable resets. If either rstctrl is non-zero
> @@ -907,6 +908,16 @@ static int omap_prm_reset_init(struct platform_device *pdev,
> map++;
> }
>
> + /* Quirk handling to assert rst_map_012 bits on reset and avoid errors */
> + if (prm->data->rstmap == rst_map_012) {
> + v = readl_relaxed(reset->prm->base + reset->prm->data->rstctrl);
> + if ((v & reset->mask) != reset->mask) {
> + dev_dbg(&pdev->dev, "Asserting all resets: %08x\n", v);
> + writel_relaxed(reset->mask, reset->prm->base +
> + reset->prm->data->rstctrl);
> + }
> + }
> +
> return devm_reset_controller_register(&pdev->dev, &reset->rcdev);
> }
>
> --
> 2.29.2
Works for me on xt875, idle now also works without userspace hack.
Tested-by: Carl Philipp Klemm <philipp@xxxxxxxx>
