* [PATCH] bus: ti-sysc: Flush posted write only after srst_udelay
@ 2023-11-24 10:41 Tony Lindgren
2023-11-24 11:48 ` Greg Kroah-Hartman
0 siblings, 1 reply; 2+ messages in thread
From: Tony Lindgren @ 2023-11-24 10:41 UTC (permalink / raw
To: linux-omap
Cc: Dhruva Gole, Greg Kroah-Hartman, Keerthy, Kevin Hilman,
Nishanth Menon, linux-kernel, linux-arm-kernel
Commit 34539b442b3b ("bus: ti-sysc: Flush posted write on enable before
reset") caused a regression reproducable on omap4 duovero where the ISS
target module can produce interconnect errors on boot. Turns out the
registers are not accessible until after a delay for devices needing
a ti,sysc-delay-us value.
Let's fix this by flushing the posted write only after the reset delay.
We do flushing also for ti,sysc-delay-us using devices as that should
trigger an interconnect error if the delay is not properly configured.
Let's also add some comments while at it.
Fixes: 34539b442b3b ("bus: ti-sysc: Flush posted write on enable before reset")
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
drivers/bus/ti-sysc.c | 18 ++++++++++++++----
1 file changed, 14 insertions(+), 4 deletions(-)
diff --git a/drivers/bus/ti-sysc.c b/drivers/bus/ti-sysc.c
--- a/drivers/bus/ti-sysc.c
+++ b/drivers/bus/ti-sysc.c
@@ -2158,13 +2158,23 @@ static int sysc_reset(struct sysc *ddata)
sysc_val = sysc_read_sysconfig(ddata);
sysc_val |= sysc_mask;
sysc_write(ddata, sysc_offset, sysc_val);
- /* Flush posted write */
+
+ /*
+ * Some devices need a delay before reading registers
+ * after reset. Presumably a srst_udelay is not needed
+ * for devices that use a rstctrl register reset.
+ */
+ if (ddata->cfg.srst_udelay)
+ fsleep(ddata->cfg.srst_udelay);
+
+ /*
+ * Flush posted write. For devices needing srst_udelay
+ * this should trigger an interconnect error if the
+ * srst_udelay value is needed but not configured.
+ */
sysc_val = sysc_read_sysconfig(ddata);
}
- if (ddata->cfg.srst_udelay)
- fsleep(ddata->cfg.srst_udelay);
-
if (ddata->post_reset_quirk)
ddata->post_reset_quirk(ddata);
--
2.42.1
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: [PATCH] bus: ti-sysc: Flush posted write only after srst_udelay
2023-11-24 10:41 [PATCH] bus: ti-sysc: Flush posted write only after srst_udelay Tony Lindgren
@ 2023-11-24 11:48 ` Greg Kroah-Hartman
0 siblings, 0 replies; 2+ messages in thread
From: Greg Kroah-Hartman @ 2023-11-24 11:48 UTC (permalink / raw
To: Tony Lindgren
Cc: linux-omap, Dhruva Gole, Keerthy, Kevin Hilman, Nishanth Menon,
linux-kernel, linux-arm-kernel
On Fri, Nov 24, 2023 at 12:41:33PM +0200, Tony Lindgren wrote:
> Commit 34539b442b3b ("bus: ti-sysc: Flush posted write on enable before
> reset") caused a regression reproducable on omap4 duovero where the ISS
> target module can produce interconnect errors on boot. Turns out the
> registers are not accessible until after a delay for devices needing
> a ti,sysc-delay-us value.
>
> Let's fix this by flushing the posted write only after the reset delay.
> We do flushing also for ti,sysc-delay-us using devices as that should
> trigger an interconnect error if the delay is not properly configured.
>
> Let's also add some comments while at it.
>
> Fixes: 34539b442b3b ("bus: ti-sysc: Flush posted write on enable before reset")
> Signed-off-by: Tony Lindgren <tony@atomide.com>
> ---
> drivers/bus/ti-sysc.c | 18 ++++++++++++++----
> 1 file changed, 14 insertions(+), 4 deletions(-)
Hi,
This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him
a patch that has triggered this response. He used to manually respond
to these common problems, but in order to save his sanity (he kept
writing the same thing over and over, yet to different people), I was
created. Hopefully you will not take offence and will fix the problem
in your patch and resubmit it so that it can be accepted into the Linux
kernel tree.
You are receiving this message because of the following common error(s)
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Documentation/process/stable-kernel-rules.rst file for how to resolve
this.
If you wish to discuss this problem further, or you have questions about
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Greg will reply once he has dug out from the pending patches received
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thanks,
greg k-h's patch email bot
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