Revision b05ea3314390e9cb3c27cf2928d48e38fef97050 authored by AngeloGioacchino Del Regno on 11 October 2022, 13:55:48 UTC, committed by Stephen Boyd on 14 October 2022, 20:38:20 UTC
Since commit 262ca38f4b6e ("clk: Stop forwarding clk_rate_requests
to the parent"), the clk_rate_request is .. as the title says, not
forwarded anymore to the parent: this produces an issue with the
MediaTek clock MUX driver during GPU DVFS on MT8195, but not on
MT8192 or others.
This is because, differently from others, like MT8192 where all of
the clocks in the MFG parents tree are of mtk_mux type, but in the
parent tree of MT8195's MFG clock, we have one mtk_mux clock and
one (clk framework generic) mux clock, like so:
names: mfg_bg3d -> mfg_ck_fast_ref -> top_mfg_core_tmp (or) mfgpll
types: mtk_gate -> mux -> mtk_mux (or) mtk_pll
To solve this issue and also keep the GPU DVFS clocks code working
as expected, wire up a .determine_rate() callback for the mtk_mux
ops; for that, the standard clk_mux_determine_rate_flags() was used
as it was possible to.
This commit was successfully tested on MT6795 Xperia M5, MT8173 Elm,
MT8192 Spherion and MT8195 Tomato; no regressions were seen.
For the sake of some more documentation about this issue here's the
trace of it:
[ 12.211587] ------------[ cut here ]------------
[ 12.211589] WARNING: CPU: 6 PID: 78 at drivers/clk/clk.c:1462 clk_core_init_rate_req+0x84/0x90
[ 12.211593] Modules linked in: stp crct10dif_ce mtk_adsp_common llc rfkill snd_sof_xtensa_dsp
panfrost(+) sbs_battery cros_ec_lid_angle cros_ec_sensors snd_sof_of
cros_ec_sensors_core hid_multitouch cros_usbpd_logger snd_sof gpu_sched
snd_sof_utils fuse ipv6
[ 12.211614] CPU: 6 PID: 78 Comm: kworker/u16:2 Tainted: G W 6.0.0-next-20221011+ #58
[ 12.211616] Hardware name: Acer Tomato (rev2) board (DT)
[ 12.211617] Workqueue: devfreq_wq devfreq_monitor
[ 12.211620] pstate: 40400009 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[ 12.211622] pc : clk_core_init_rate_req+0x84/0x90
[ 12.211625] lr : clk_core_forward_rate_req+0xa4/0xe4
[ 12.211627] sp : ffff80000893b8e0
[ 12.211628] x29: ffff80000893b8e0 x28: ffffdddf92f9b000 x27: ffff46a2c0e8bc05
[ 12.211632] x26: ffff46a2c1041200 x25: 0000000000000000 x24: 00000000173eed80
[ 12.211636] x23: ffff80000893b9c0 x22: ffff80000893b940 x21: 0000000000000000
[ 12.211641] x20: ffff46a2c1039f00 x19: ffff46a2c1039f00 x18: 0000000000000000
[ 12.211645] x17: 0000000000000038 x16: 000000000000d904 x15: 0000000000000003
[ 12.211649] x14: ffffdddf9357ce48 x13: ffffdddf935e71c8 x12: 000000000004803c
[ 12.211653] x11: 00000000a867d7ad x10: 00000000a867d7ad x9 : ffffdddf90c28df4
[ 12.211657] x8 : ffffdddf9357a980 x7 : 0000000000000000 x6 : 0000000000000004
[ 12.211661] x5 : ffffffffffffffc8 x4 : 00000000173eed80 x3 : ffff80000893b940
[ 12.211665] x2 : 00000000173eed80 x1 : ffff80000893b940 x0 : 0000000000000000
[ 12.211669] Call trace:
[ 12.211670] clk_core_init_rate_req+0x84/0x90
[ 12.211673] clk_core_round_rate_nolock+0xe8/0x10c
[ 12.211675] clk_mux_determine_rate_flags+0x174/0x1f0
[ 12.211677] clk_mux_determine_rate+0x1c/0x30
[ 12.211680] clk_core_determine_round_nolock+0x74/0x130
[ 12.211682] clk_core_round_rate_nolock+0x58/0x10c
[ 12.211684] clk_core_round_rate_nolock+0xf4/0x10c
[ 12.211686] clk_core_set_rate_nolock+0x194/0x2ac
[ 12.211688] clk_set_rate+0x40/0x94
[ 12.211691] _opp_config_clk_single+0x38/0xa0
[ 12.211693] _set_opp+0x1b0/0x500
[ 12.211695] dev_pm_opp_set_rate+0x120/0x290
[ 12.211697] panfrost_devfreq_target+0x3c/0x50 [panfrost]
[ 12.211705] devfreq_set_target+0x8c/0x2d0
[ 12.211707] devfreq_update_target+0xcc/0xf4
[ 12.211708] devfreq_monitor+0x40/0x1d0
[ 12.211710] process_one_work+0x294/0x664
[ 12.211712] worker_thread+0x7c/0x45c
[ 12.211713] kthread+0x104/0x110
[ 12.211716] ret_from_fork+0x10/0x20
[ 12.211718] irq event stamp: 7102
[ 12.211719] hardirqs last enabled at (7101): [<ffffdddf904ea5a0>] finish_task_switch.isra.0+0xec/0x2f0
[ 12.211723] hardirqs last disabled at (7102): [<ffffdddf91794b74>] el1_dbg+0x24/0x90
[ 12.211726] softirqs last enabled at (6716): [<ffffdddf90410be4>] __do_softirq+0x414/0x588
[ 12.211728] softirqs last disabled at (6507): [<ffffdddf904171d8>] ____do_softirq+0x18/0x24
[ 12.211730] ---[ end trace 0000000000000000 ]---
Fixes: 262ca38f4b6e ("clk: Stop forwarding clk_rate_requests to the parent")
Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20221011135548.318323-1-angelogioacchino.delregno@collabora.com
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
1 parent 589a200
ac97_bus.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Linux driver model AC97 bus interface
*
* Author: Nicolas Pitre
* Created: Jan 14, 2005
* Copyright: (C) MontaVista Software Inc.
*/
#include <linux/module.h>
#include <linux/init.h>
#include <linux/device.h>
#include <linux/string.h>
#include <sound/ac97_codec.h>
/*
* snd_ac97_check_id() - Reads and checks the vendor ID of the device
* @ac97: The AC97 device to check
* @id: The ID to compare to
* @id_mask: Mask that is applied to the device ID before comparing to @id
*
* If @id is 0 this function returns true if the read device vendor ID is
* a valid ID. If @id is non 0 this functions returns true if @id
* matches the read vendor ID. Otherwise the function returns false.
*/
static bool snd_ac97_check_id(struct snd_ac97 *ac97, unsigned int id,
unsigned int id_mask)
{
ac97->id = ac97->bus->ops->read(ac97, AC97_VENDOR_ID1) << 16;
ac97->id |= ac97->bus->ops->read(ac97, AC97_VENDOR_ID2);
if (ac97->id == 0x0 || ac97->id == 0xffffffff)
return false;
if (id != 0 && id != (ac97->id & id_mask))
return false;
return true;
}
/**
* snd_ac97_reset() - Reset AC'97 device
* @ac97: The AC'97 device to reset
* @try_warm: Try a warm reset first
* @id: Expected device vendor ID
* @id_mask: Mask that is applied to the device ID before comparing to @id
*
* This function resets the AC'97 device. If @try_warm is true the function
* first performs a warm reset. If the warm reset is successful the function
* returns 1. Otherwise or if @try_warm is false the function issues cold reset
* followed by a warm reset. If this is successful the function returns 0,
* otherwise a negative error code. If @id is 0 any valid device ID will be
* accepted, otherwise only the ID that matches @id and @id_mask is accepted.
*/
int snd_ac97_reset(struct snd_ac97 *ac97, bool try_warm, unsigned int id,
unsigned int id_mask)
{
const struct snd_ac97_bus_ops *ops = ac97->bus->ops;
if (try_warm && ops->warm_reset) {
ops->warm_reset(ac97);
if (snd_ac97_check_id(ac97, id, id_mask))
return 1;
}
if (ops->reset)
ops->reset(ac97);
if (ops->warm_reset)
ops->warm_reset(ac97);
if (snd_ac97_check_id(ac97, id, id_mask))
return 0;
return -ENODEV;
}
EXPORT_SYMBOL_GPL(snd_ac97_reset);
/*
* Let drivers decide whether they want to support given codec from their
* probe method. Drivers have direct access to the struct snd_ac97
* structure and may decide based on the id field amongst other things.
*/
static int ac97_bus_match(struct device *dev, struct device_driver *drv)
{
return 1;
}
struct bus_type ac97_bus_type = {
.name = "ac97",
.match = ac97_bus_match,
};
static int __init ac97_bus_init(void)
{
return bus_register(&ac97_bus_type);
}
subsys_initcall(ac97_bus_init);
static void __exit ac97_bus_exit(void)
{
bus_unregister(&ac97_bus_type);
}
module_exit(ac97_bus_exit);
EXPORT_SYMBOL(ac97_bus_type);
MODULE_LICENSE("GPL");
Computing file changes ...
