From: Shengjiu Wang <shengjiu.wang@nxp.com>
To: abelvesa@kernel.org, peng.fan@nxp.com, mturquette@baylibre.com,
sboyd@kernel.org, shawnguo@kernel.org, s.hauer@pengutronix.de,
kernel@pengutronix.de, festevam@gmail.com, imx@lists.linux.dev,
shengjiu.wang@gmail.com
Cc: linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v2] clk: imx: imx8mp: Add delay after power up
Date: Mon, 6 May 2024 11:35:02 +0800 [thread overview]
Message-ID: <1714966502-27784-1-git-send-email-shengjiu.wang@nxp.com> (raw)
According to comments in drivers/pmdomain/imx/gpcv2.c:
/* request the ADB400 to power up */
if (domain->bits.hskreq) {
regmap_update_bits(domain->regmap, domain->regs->hsk,
domain->bits.hskreq, domain->bits.hskreq);
/*
* ret = regmap_read_poll_timeout(domain->regmap, domain->regs->hsk, reg_val,
* (reg_val & domain->bits.hskack), 0,
* USEC_PER_MSEC);
* Technically we need the commented code to wait handshake. But that needs
* the BLK-CTL module BUS clk-en bit being set.
*
* There is a separate BLK-CTL module and we will have such a driver for it,
* that driver will set the BUS clk-en bit and handshake will be triggered
* automatically there. Just add a delay and suppose the handshake finish
* after that.
*/
}
The BLK-CTL module needs to add delay to wait for a handshake request finished
before accessing registers, which is just after the enabling of the power domain.
Otherwise there is error:
[ 2.181035] Kernel panic - not syncing: Asynchronous SError Interrupt
[ 2.181038] CPU: 1 PID: 48 Comm: kworker/u16:2 Not tainted 6.9.0-rc5-next-20240424-00003-g21cec88845c6 #171
[ 2.181047] Hardware name: NXP i.MX8MPlus EVK board (DT)
[ 2.181050] Workqueue: events_unbound deferred_probe_work_func
[ 2.181064] Call trace:
[...]
[ 2.181142] arm64_serror_panic+0x6c/0x78
[ 2.181149] do_serror+0x3c/0x70
[ 2.181157] el1h_64_error_handler+0x30/0x48
[ 2.181164] el1h_64_error+0x64/0x68
[ 2.181171] clk_imx8mp_audiomix_runtime_resume+0x34/0x44
[ 2.181183] __genpd_runtime_resume+0x30/0x80
[ 2.181195] genpd_runtime_resume+0x110/0x244
[ 2.181205] __rpm_callback+0x48/0x1d8
[ 2.181213] rpm_callback+0x68/0x74
[ 2.181224] rpm_resume+0x468/0x6c0
[ 2.181234] __pm_runtime_resume+0x50/0x94
[ 2.181243] pm_runtime_get_suppliers+0x60/0x8c
[ 2.181258] __driver_probe_device+0x48/0x12c
[ 2.181268] driver_probe_device+0xd8/0x15c
[ 2.181278] __device_attach_driver+0xb8/0x134
[ 2.181290] bus_for_each_drv+0x84/0xe0
[ 2.181302] __device_attach+0x9c/0x188
[ 2.181312] device_initial_probe+0x14/0x20
[ 2.181323] bus_probe_device+0xac/0xb0
[ 2.181334] deferred_probe_work_func+0x88/0xc0
[ 2.181344] process_one_work+0x150/0x290
[ 2.181357] worker_thread+0x2f8/0x408
[ 2.181370] kthread+0x110/0x114
[ 2.181381] ret_from_fork+0x10/0x20
[ 2.181391] SMP: stopping secondary CPUs
Fixes: 1496dd413b2e ("clk: imx: imx8mp: Add pm_runtime support for power saving")
Reported-by: Francesco Dolcini <francesco@dolcini.it>
Signed-off-by: Shengjiu Wang <shengjiu.wang@nxp.com>
Revewied-by: Peng Fan <peng.fan@nxp.com>
---
changes in v2:
- reduce size of panic log in commit message
drivers/clk/imx/clk-imx8mp-audiomix.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/clk/imx/clk-imx8mp-audiomix.c b/drivers/clk/imx/clk-imx8mp-audiomix.c
index b381d6f784c8..ae2c0f254225 100644
--- a/drivers/clk/imx/clk-imx8mp-audiomix.c
+++ b/drivers/clk/imx/clk-imx8mp-audiomix.c
@@ -6,6 +6,7 @@
*/
#include <linux/clk-provider.h>
+#include <linux/delay.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/mod_devicetable.h>
@@ -360,6 +361,12 @@ static int clk_imx8mp_audiomix_runtime_suspend(struct device *dev)
static int clk_imx8mp_audiomix_runtime_resume(struct device *dev)
{
+ /*
+ * According to the drivers/pmdomain/imx/gpcv2.c
+ * need to wait for handshake request to propagate
+ */
+ udelay(5);
+
clk_imx8mp_audiomix_save_restore(dev, false);
return 0;
--
2.34.1
next reply other threads:[~2024-05-06 4:02 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-06 3:35 Shengjiu Wang [this message]
2024-05-06 18:21 ` [PATCH v2] clk: imx: imx8mp: Add delay after power up Frank Li
2024-05-07 1:44 ` Shengjiu Wang
2024-05-07 3:41 ` Frank Li
2024-05-07 3:44 ` Shengjiu Wang
2024-05-07 4:02 ` Frank Li
2024-05-07 8:04 ` Shengjiu Wang
2024-05-10 18:38 ` Frank Li
2024-05-11 3:09 ` Shengjiu Wang
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