[PATCH AUTOSEL 5.10 01/36] soc: ti: omap-prm: Fix boot time errors for rst_map_012 bits 0 and 1

[Sasha Levin]

From: Tony Lindgren <tony at atomide.com>

[ Upstream commit 7078a5ba7a58e5db07583b176f8a03e0b8714731 ]

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 at uvos.xyz>
Cc: Philipp Zabel <p.zabel at pengutronix.de>
Cc: Santosh Shilimkar <ssantosh at kernel.org>
Cc: Suman Anna <s-anna at ti.com>
Cc: Tero Kristo <t-kristo at ti.com>
Tested-by: Carl Philipp Klemm <philipp at uvos.xyz>
Signed-off-by: Tony Lindgren <tony at atomide.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 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
index 4d41dc3cdce1f..c8b14b3a171f7 100644
--- a/drivers/soc/ti/omap_prm.c
+++ b/drivers/soc/ti/omap_prm.c
@@ -552,6 +552,7 @@ 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
@@ -599,6 +600,16 @@ 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);
 }
 
-- 
2.27.0