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Subject[PATCH 1/3] reset: microchip-sparx5: issue a reset on startup
Date
Originally this was used in by the switch core driver to issue a reset.
But it turns out, this isn't just a switch core reset but instead it
will reset almost the complete SoC.

Instead of adding almost all devices of the SoC a shared reset line,
issue the reset once early on startup. Keep the reset controller for
backwards compatibility, but make the actual reset a noop.

Suggested-by: Philipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: Michael Walle <michael@walle.cc>
---
drivers/reset/reset-microchip-sparx5.c | 22 +++++++++++++++++-----
1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/drivers/reset/reset-microchip-sparx5.c b/drivers/reset/reset-microchip-sparx5.c
index 00b612a0effa..f3528dd1d084 100644
--- a/drivers/reset/reset-microchip-sparx5.c
+++ b/drivers/reset/reset-microchip-sparx5.c
@@ -33,11 +33,8 @@ static struct regmap_config sparx5_reset_regmap_config = {
.reg_stride = 4,
};

-static int sparx5_switch_reset(struct reset_controller_dev *rcdev,
- unsigned long id)
+static int sparx5_switch_reset(struct mchp_reset_context *ctx)
{
- struct mchp_reset_context *ctx =
- container_of(rcdev, struct mchp_reset_context, rcdev);
u32 val;

/* Make sure the core is PROTECTED from reset */
@@ -54,8 +51,14 @@ static int sparx5_switch_reset(struct reset_controller_dev *rcdev,
1, 100);
}

+static int sparx5_reset_noop(struct reset_controller_dev *rcdev,
+ unsigned long id)
+{
+ return 0;
+}
+
static const struct reset_control_ops sparx5_reset_ops = {
- .reset = sparx5_switch_reset,
+ .reset = sparx5_reset_noop,
};

static int mchp_sparx5_map_syscon(struct platform_device *pdev, char *name,
@@ -122,6 +125,11 @@ static int mchp_sparx5_reset_probe(struct platform_device *pdev)
ctx->rcdev.of_node = dn;
ctx->props = device_get_match_data(&pdev->dev);

+ /* Issue the reset very early, our actual reset callback is a noop. */
+ err = sparx5_switch_reset(ctx);
+ if (err)
+ return err;
+
return devm_reset_controller_register(&pdev->dev, &ctx->rcdev);
}

@@ -163,6 +171,10 @@ static int __init mchp_sparx5_reset_init(void)
return platform_driver_register(&mchp_sparx5_reset_driver);
}

+/*
+ * Because this is a global reset, keep this postcore_initcall() to issue the
+ * reset as early as possible during the kernel startup.
+ */
postcore_initcall(mchp_sparx5_reset_init);

MODULE_DESCRIPTION("Microchip Sparx5 switch reset driver");
--
2.30.2
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