kernel/drivers/clk/qcom/gdsc.h, branch linux-6.5.y

clk: qcom: gdsc: Remove direct runtime PM calls

2022-11-04T18:53:49Z

We shouldn't be calling runtime PM APIs from within the genpd enable/disable path for a couple reasons. First, this causes an AA lockdep splat[1] because genpd can call into genpd code again while holding the genpd lock. WARNING: possible recursive locking detected 5.19.0-rc2-lockdep+ #7 Not tainted -------------------------------------------- kworker/2:1/49 is trying to acquire lock: ffffffeea0370788 (&genpd->mlock){+.+.}-{3:3}, at: genpd_lock_mtx+0x24/0x30 but task is already holding lock: ffffffeea03710a8 (&genpd->mlock){+.+.}-{3:3}, at: genpd_lock_mtx+0x24/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&genpd->mlock); lock(&genpd->mlock); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by kworker/2:1/49: #0: 74ffff80811a5748 ((wq_completion)pm){+.+.}-{0:0}, at: process_one_work+0x320/0x5fc #1: ffffffc008537cf8 ((work_completion)(&genpd->power_off_work)){+.+.}-{0:0}, at: process_one_work+0x354/0x5fc #2: ffffffeea03710a8 (&genpd->mlock){+.+.}-{3:3}, at: genpd_lock_mtx+0x24/0x30 stack backtrace: CPU: 2 PID: 49 Comm: kworker/2:1 Not tainted 5.19.0-rc2-lockdep+ #7 Hardware name: Google Lazor (rev3 - 8) with KB Backlight (DT) Workqueue: pm genpd_power_off_work_fn Call trace: dump_backtrace+0x1a0/0x200 show_stack+0x24/0x30 dump_stack_lvl+0x7c/0xa0 dump_stack+0x18/0x44 __lock_acquire+0xb38/0x3634 lock_acquire+0x180/0x2d4 __mutex_lock_common+0x118/0xe30 mutex_lock_nested+0x70/0x7c genpd_lock_mtx+0x24/0x30 genpd_runtime_suspend+0x2f0/0x414 __rpm_callback+0xdc/0x1b8 rpm_callback+0x4c/0xcc rpm_suspend+0x21c/0x5f0 rpm_idle+0x17c/0x1e0 __pm_runtime_idle+0x78/0xcc gdsc_disable+0x24c/0x26c _genpd_power_off+0xd4/0x1c4 genpd_power_off+0x2d8/0x41c genpd_power_off_work_fn+0x60/0x94 process_one_work+0x398/0x5fc worker_thread+0x42c/0x6c4 kthread+0x194/0x1b4 ret_from_fork+0x10/0x20 Second, this confuses runtime PM on CoachZ for the camera devices by causing the camera clock controller's runtime PM usage_count to go negative after resuming from suspend. This is because runtime PM is being used on the clock controller while runtime PM is disabled for the device. The reason for the negative count is because a GDSC is represented as a genpd and each genpd that is attached to a device is resumed during the noirq phase of system wide suspend/resume (see the noirq suspend ops assignment in pm_genpd_init() for more details). The camera GDSCs are attached to camera devices with the 'power-domains' property in DT. Every device has runtime PM disabled in the late system suspend phase via __device_suspend_late(). Runtime PM is not usable until runtime PM is enabled in device_resume_early(). The noirq phases run after the 'late' and before the 'early' phase of suspend/resume. When the genpds are resumed in genpd_resume_noirq(), we call down into gdsc_enable() that calls pm_runtime_resume_and_get() and that returns -EACCES to indicate failure to resume because runtime PM is disabled for all devices. Upon closer inspection, calling runtime PM APIs like this in the GDSC driver doesn't make sense. It was intended to make sure the GDSC for the clock controller providing other GDSCs was enabled, specifically the MMCX GDSC for the display clk controller on SM8250 (sm8250-dispcc), so that GDSC register accesses succeeded. That will already happen because we make the 'dev->pm_domain' a parent domain of each GDSC we register in gdsc_register() via pm_genpd_add_subdomain(). When any of these GDSCs are accessed, we'll enable the parent domain (in this specific case MMCX). We also remove any getting of runtime PM during registration, because when a genpd is registered it increments the count on the parent if the genpd itself is already enabled. Cc: Dmitry Baryshkov Cc: Johan Hovold Cc: Ulf Hansson Cc: Taniya Das Cc: Satya Priya Reviewed-by: Douglas Anderson Tested-by: Douglas Anderson Cc: Matthias Kaehlcke Reported-by: Stephen Boyd Link: https://lore.kernel.org/r/CAE-0n52xbZeJ66RaKwggeRB57fUAwjvxGxfFMKOKJMKVyFTe+w@mail.gmail.com [1] Fixes: 1b771839de05 ("clk: qcom: gdsc: enable optional power domain support") Signed-off-by: Stephen Boyd Link: https://lore.kernel.org/r/20221103183030.3594899-1-swboyd@chromium.org Tested-by: Johan Hovold Reviewed-by: Johan Hovold Signed-off-by: Stephen Boyd

clk: qcom: gdsc: Fix the handling of PWRSTS_RET support

2022-09-28T02:58:38Z

GDSCs cannot be transitioned into a Retention state in SW. When either the RETAIN_MEM bit, or both the RETAIN_MEM and RETAIN_PERIPH bits are set, and the GDSC is left ON, the HW takes care of retaining the memory/logic for the domain when the parent domain transitions to power collapse/power off state. On some platforms where the parent domains lowest power state itself is Retention, just leaving the GDSC in ON (without any RETAIN_MEM/RETAIN_PERIPH bits being set) will also transition it to Retention. The existing logic handling the PWRSTS_RET seems to set the RETAIN_MEM/RETAIN_PERIPH bits if the cxcs offsets are specified but then explicitly turns the GDSC OFF as part of _gdsc_disable(). Fix that by leaving the GDSC in ON state. Signed-off-by: Rajendra Nayak Cc: AngeloGioacchino Del Regno Signed-off-by: Bjorn Andersson Link: https://lore.kernel.org/r/20220920111517.10407-1-quic_rjendra@quicinc.com

clk: qcom: gdsc: add support for collapse-vote registers

2022-06-26T03:38:02Z

Recent Qualcomm platforms have APCS collapse-vote registers that allow for sharing GDSCs with other masters (e.g. LPASS). Add support for using such vote registers instead of the control register when updating the GDSC power state. Signed-off-by: Johan Hovold Signed-off-by: Bjorn Andersson Link: https://lore.kernel.org/r/20220520100948.19622-3-johan+linaro@kernel.org

clk: qcom: gdsc: Add support to update GDSC transition delay

2022-02-25T00:11:42Z

GDSCs have multiple transition delays which are used for the GDSC FSM states. Older targets/designs required these values to be updated from gdsc code to certain default values for the FSM state to work as expected. But on the newer targets/designs the values updated from the GDSC driver can hamper the FSM state to not work as expected. On SC7180 we observe black screens because the gdsc is being enabled/disabled very rapidly and the GDSC FSM state does not work as expected. This is due to the fact that the GDSC reset value is being updated from SW. Thus add support to update the transition delay from the clock controller gdscs as required. Fixes: 45dd0e55317cc ("clk: qcom: Add support for GDSCs) Signed-off-by: Taniya Das Link: https://lore.kernel.org/r/20220223185606.3941-1-tdas@codeaurora.org Reviewed-by: Bjorn Andersson Signed-off-by: Stephen Boyd

clk: qcom: gdsc: enable optional power domain support

2021-10-15T00:58:14Z

On sm8250 dispcc and videocc registers are powered up by the MMCX power domain. Currently we use a regulator to enable this domain on demand, however this has some consequences, as genpd code is not reentrant. Make gdsc code also use pm_runtime calls to ensure that registers are accessible during the gdsc_enable/gdsc_disable operations. Signed-off-by: Dmitry Baryshkov Reviewed-by: Bjorn Andersson Link: https://lore.kernel.org/r/20210829154757.784699-6-dmitry.baryshkov@linaro.org Signed-off-by: Stephen Boyd

clk: qcom: gdsc: Implement NO_RET_PERIPH flag

2021-02-14T20:56:54Z

In some rare occasions, we want to only set the RETAIN_MEM bit, but not the RETAIN_PERIPH one: this is seen on at least SDM630/636/660's GPU-GX GDSC, where unsetting and setting back the RETAIN_PERIPH bit will generate chaos and panics during GPU suspend time (mainly, the chaos is unaligned access). For this reason, introduce a new NO_RET_PERIPH flag to the GDSC driver to address this corner case. Signed-off-by: AngeloGioacchino Del Regno Link: https://lore.kernel.org/r/20210113183817.447866-8-angelogioacchino.delregno@somainline.org Signed-off-by: Stephen Boyd

clk: qcom: gdsc: Add support to enable retention of GSDCR

2020-07-24T20:04:48Z

Add support for the RETAIN_FF_ENABLE feature which enables the usage of retention registers. These registers maintain their state after disabling and re-enabling a GDSC. Signed-off-by: Taniya Das Link: https://lore.kernel.org/r/1595606878-2664-2-git-send-email-tdas@codeaurora.org Signed-off-by: Stephen Boyd

clk: qcom: add common gdsc_gx_do_nothing_enable for gpucc drivers

2020-07-24T08:51:26Z

All gpucc drivers need this, so move it to common code instead of duplicating it in every gpucc driver. Signed-off-by: Jonathan Marek Tested-by: Dmitry Baryshkov Link: https://lore.kernel.org/r/20200709135251.643-10-jonathan@marek.ca Signed-off-by: Stephen Boyd

clk: qcom: gdsc: Handle GDSC regulator supplies

2020-05-14T21:23:38Z

Certain GDSCs, such as the GPU_GX on MSM8996, requires that the upstream regulator supply is powered in order to be turned on. It's not guaranteed that the bootloader will leave these supplies on and the driver core will attempt to enable any GDSCs before allowing the individual drivers to probe defer on the PMIC regulator driver not yet being present. So the gdsc driver needs to be made aware of supplying regulators and probe defer on their absence, and it needs to enable and disable the regulator accordingly. Voltage adjustments of the supplying regulator are deferred to the client drivers themselves. Signed-off-by: Bjorn Andersson Link: https://lkml.kernel.org/r/20200417070044.1376212-2-bjorn.andersson@linaro.org Reviewed-by: Vinod Koul Signed-off-by: Stephen Boyd

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 284

2019-06-05T15:36:37Z

Based on 1 normalized pattern(s): this program is free software you can redistribute it and or modify it under the terms of the gnu general public license version 2 and only version 2 as published by the free software foundation this program is distributed in the hope that it will be useful but without any warranty without even the implied warranty of merchantability or fitness for a particular purpose see the gnu general public license for more details extracted by the scancode license scanner the SPDX license identifier GPL-2.0-only has been chosen to replace the boilerplate/reference in 294 file(s). Signed-off-by: Thomas Gleixner Reviewed-by: Allison Randal Reviewed-by: Alexios Zavras Cc: linux-spdx@vger.kernel.org Link: https://lkml.kernel.org/r/20190529141900.825281744@linutronix.de Signed-off-by: Greg Kroah-Hartman