From 77bed0960b0a39b62814cb5972917770b49cfe63 Mon Sep 17 00:00:00 2001 From: Shengjiu Wang Date: Mon, 6 May 2024 11:35:02 +0800 Subject: [PATCH] clk: imx: imx8mp: Add delay after power up 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 Signed-off-by: Shengjiu Wang Revewied-by: Peng Fan --- 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 b381d6f784c890..ae2c0f25422551 100644 --- a/drivers/clk/imx/clk-imx8mp-audiomix.c +++ b/drivers/clk/imx/clk-imx8mp-audiomix.c @@ -6,6 +6,7 @@ */ #include +#include #include #include #include @@ -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;