From: Tony Lindgren <tony@atomide.com>
To: linux-omap@vger.kernel.org
Cc: Dhruva Gole <d-gole@ti.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Keerthy <j-keerthy@ti.com>, Kevin Hilman <khilman@baylibre.com>,
Nishanth Menon <nm@ti.com>,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org
Subject: [PATCH] bus: ti-sysc: Flush posted write only after srst_udelay
Date: Fri, 24 Nov 2023 12:41:33 +0200 [thread overview]
Message-ID: <20231124104133.19100-1-tony@atomide.com> (raw)
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
next reply other threads:[~2023-11-24 10:42 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-11-24 10:41 Tony Lindgren [this message]
2023-11-24 11:48 ` [PATCH] bus: ti-sysc: Flush posted write only after srst_udelay Greg Kroah-Hartman
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