drm/msm/gpu: Fix crash when throttling GPU immediately during boot

In the Linux kernel, the following vulnerability has been resolved:

drm/msm/gpu: Fix crash when throttling GPU immediately during boot

There is a small chance that the GPU is already hot during boot. In that

case, the call to of_devfreq_cooling_register() will immediately try to

apply devfreq cooling, as seen in the following crash:

Unable to handle kernel paging request at virtual address 0000000000014110

pc : a6xx_gpu_busy+0x1c/0x58 [msm]

lr : msm_devfreq_get_dev_status+0xbc/0x140 [msm]

Call trace:

a6xx_gpu_busy+0x1c/0x58 [msm] (P)

devfreq_simple_ondemand_func+0x3c/0x150

devfreq_update_target+0x44/0xd8

qos_max_notifier_call+0x30/0x84

blocking_notifier_call_chain+0x6c/0xa0

pm_qos_update_target+0xd0/0x110

freq_qos_apply+0x3c/0x74

apply_constraint+0x88/0x148

__dev_pm_qos_update_request+0x7c/0xcc

dev_pm_qos_update_request+0x38/0x5c

devfreq_cooling_set_cur_state+0x98/0xf0

__thermal_cdev_update+0x64/0xb4

thermal_cdev_update+0x4c/0x58

step_wise_manage+0x1f0/0x318

__thermal_zone_device_update+0x278/0x424

__thermal_cooling_device_register+0x2bc/0x308

thermal_of_cooling_device_register+0x10/0x1c

of_devfreq_cooling_register_power+0x240/0x2bc

of_devfreq_cooling_register+0x14/0x20

msm_devfreq_init+0xc4/0x1a0 [msm]

msm_gpu_init+0x304/0x574 [msm]

adreno_gpu_init+0x1c4/0x2e0 [msm]

a6xx_gpu_init+0x5c8/0x9c8 [msm]

adreno_bind+0x2a8/0x33c [msm]

...

At this point we haven't initialized the GMU at all yet, so we cannot read

the GMU registers inside a6xx_gpu_busy(). A similar issue was fixed before

in commit 6694482a70e9 ("drm/msm: Avoid unclocked GMU register access in

6xx gpu_busy"): msm_devfreq_init() does call devfreq_suspend_device(), but

unlike msm_devfreq_suspend(), it doesn't set the df->suspended flag

accordingly. This means the df->suspended flag does not match the actual

devfreq state after initialization and msm_devfreq_get_dev_status() will

end up accessing GMU registers, causing the crash.

Fix this by setting df->suspended correctly during initialization.

Patchwork: https://patchwork.freedesktop.org/patch/650772/