From: Tony Lindgren <tony@atomide.com>
Date: Mon, 16 Nov 2020 10:57:13 +0000 (+0200)
Subject: bus: ti-sysc: Assert reset only after disabling clocks
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=4097c9a64d1009d97dcee772bd8b15381bc7507d;p=linux.git

bus: ti-sysc: Assert reset only after disabling clocks

The rstctrl reset must be asserted after gating the module clock as
described in the TRM at least for IVA. Otherwise the rstctrl reset
done with module clock enabled can hang the system.

Note that this issue is has been only seen with related IVA changes
that we do not currently have merged. So probably no need to apply
this patch as a fix.

Signed-off-by: Tony Lindgren <tony@atomide.com>
---

diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c
index 16132e6e91f8d..2b99fd5a47404 100644
--- a/drivers/bus/ti-sysc.c
+++ b/drivers/bus/ti-sysc.c
@@ -1222,10 +1222,10 @@ static int __maybe_unused sysc_runtime_suspend(struct device *dev)
 	ddata->enabled = false;
 
 err_allow_idle:
-	reset_control_assert(ddata->rsts);
-
 	sysc_clkdm_allow_idle(ddata);
 
+	reset_control_assert(ddata->rsts);
+
 	return error;
 }
 
@@ -1945,6 +1945,7 @@ static int sysc_reset(struct sysc *ddata)
  */
 static int sysc_init_module(struct sysc *ddata)
 {
+	bool rstctrl_deasserted = false;
 	int error = 0;
 
 	error = sysc_clockdomain_init(ddata);
@@ -1969,6 +1970,7 @@ static int sysc_init_module(struct sysc *ddata)
 		error = reset_control_deassert(ddata->rsts);
 		if (error)
 			goto err_main_clocks;
+		rstctrl_deasserted = true;
 	}
 
 	ddata->revision = sysc_read_revision(ddata);
@@ -1978,13 +1980,13 @@ static int sysc_init_module(struct sysc *ddata)
 	if (ddata->legacy_mode) {
 		error = sysc_legacy_init(ddata);
 		if (error)
-			goto err_reset;
+			goto err_main_clocks;
 	}
 
 	if (!ddata->legacy_mode) {
 		error = sysc_enable_module(ddata->dev);
 		if (error)
-			goto err_reset;
+			goto err_main_clocks;
 	}
 
 	error = sysc_reset(ddata);
@@ -1994,10 +1996,6 @@ static int sysc_init_module(struct sysc *ddata)
 	if (error && !ddata->legacy_mode)
 		sysc_disable_module(ddata->dev);
 
-err_reset:
-	if (error && !(ddata->cfg.quirks & SYSC_QUIRK_NO_RESET_ON_INIT))
-		reset_control_assert(ddata->rsts);
-
 err_main_clocks:
 	if (error)
 		sysc_disable_main_clocks(ddata);
@@ -2008,6 +2006,10 @@ err_opt_clocks:
 		sysc_clkdm_allow_idle(ddata);
 	}
 
+	if (error && rstctrl_deasserted &&
+	    !(ddata->cfg.quirks & SYSC_QUIRK_NO_RESET_ON_INIT))
+		reset_control_assert(ddata->rsts);
+
 	return error;
 }
 
@@ -2975,9 +2977,6 @@ static int sysc_probe(struct platform_device *pdev)
 	}
 
 	/* Balance use counts as PM runtime should have enabled these all */
-	if (!(ddata->cfg.quirks & SYSC_QUIRK_NO_RESET_ON_INIT))
-		reset_control_assert(ddata->rsts);
-
 	if (!(ddata->cfg.quirks &
 	      (SYSC_QUIRK_NO_IDLE | SYSC_QUIRK_NO_IDLE_ON_INIT))) {
 		sysc_disable_main_clocks(ddata);
@@ -2985,6 +2984,9 @@ static int sysc_probe(struct platform_device *pdev)
 		sysc_clkdm_allow_idle(ddata);
 	}
 
+	if (!(ddata->cfg.quirks & SYSC_QUIRK_NO_RESET_ON_INIT))
+		reset_control_assert(ddata->rsts);
+
 	sysc_show_registers(ddata);
 
 	ddata->dev->type = &sysc_device_type;