[PATCH AUTOSEL 5.8 22/72] firmware: arm_scmi: Fix SCMI genpd domain probing

Sasha Levin
2020-08-08T23:51:02Z

From: Cristian Marussi <cristian.marussi@arm.com>

[ Upstream commit e0f1a30cf184821499eeb67daedd7a3f21bbcb0b ]

When, at probe time, an SCMI communication failure inhibits the capacity
to query power domains states, such domains should be skipped.

Registering partially initialized SCMI power domains with genpd will
causes kernel panic.

arm-scmi timed out in resp(caller: scmi_power_state_get+0xa4/0xd0)
scmi-power-domain scmi_dev.2: failed to get state for domain 9
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
Mem abort info:
ESR = 0x96000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
Data abort info:
ISV = 0, ISS = 0x00000006
CM = 0, WnR = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=00000009f3691000
[0000000000000000] pgd=00000009f1ca0003, p4d=00000009f1ca0003, pud=00000009f35ea003, pmd=0000000000000000
Internal error: Oops: 96000006 [#1] PREEMPT SMP
CPU: 2 PID: 381 Comm: bash Not tainted 5.8.0-rc1-00011-gebd118c2cca8 #2
Hardware name: ARM LTD ARM Juno Development Platform/ARM Juno Development Platform, BIOS EDK II Jan 3 2020
Internal error: Oops: 96000006 [#1] PREEMPT SMP
pstate: 80000005 (Nzcv daif -PAN -UAO BTYPE=--)
pc : of_genpd_add_provider_onecell+0x98/0x1f8
lr : of_genpd_add_provider_onecell+0x48/0x1f8
Call trace:
of_genpd_add_provider_onecell+0x98/0x1f8
scmi_pm_domain_probe+0x174/0x1e8
scmi_dev_probe+0x90/0xe0
really_probe+0xe4/0x448
driver_probe_device+0xfc/0x168
device_driver_attach+0x7c/0x88
bind_store+0xe8/0x128
drv_attr_store+0x2c/0x40
sysfs_kf_write+0x4c/0x60
kernfs_fop_write+0x114/0x230
__vfs_write+0x24/0x50
vfs_write+0xbc/0x1e0
ksys_write+0x70/0xf8
__arm64_sys_write+0x24/0x30
el0_svc_common.constprop.3+0x94/0x160
do_el0_svc+0x2c/0x98
el0_sync_handler+0x148/0x1a8
el0_sync+0x158/0x180

Do not register any power domain that failed to be queried with genpd.

Fixes: 898216c97ed2 ("firmware: arm_scmi: add device power domain support using genpd")
Link: https://lore.kernel.org/r/20200619220330.12217-1-cristian.marussi@arm.com
Signed-off-by: Cristian Marussi <cristian.marussi@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/firmware/arm_scmi/scmi_pm_domain.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/firmware/arm_scmi/scmi_pm_domain.c b/drivers/firmware/arm_scmi/scmi_pm_domain.c
index bafbfe358f97d..9e44479f02842 100644
--- a/drivers/firmware/arm_scmi/scmi_pm_domain.c
+++ b/drivers/firmware/arm_scmi/scmi_pm_domain.c
@@ -85,7 +85,10 @@ static int scmi_pm_domain_probe(struct scmi_device *sdev)
for (i = 0; i < num_domains; i++, scmi_pd++) {
u32 state;

- domains[i] = &scmi_pd->genpd;
+ if (handle->power_ops->state_get(handle, i, &state)) {
+ dev_warn(dev, "failed to get state for domain %d\n", i);
+ continue;
+ }

scmi_pd->domain = i;
scmi_pd->handle = handle;
@@ -94,13 +97,10 @@ static int scmi_pm_domain_probe(struct scmi_device *sdev)
scmi_pd->genpd.power_off = scmi_pd_power_off;
scmi_pd->genpd.power_on = scmi_pd_power_on;

- if (handle->power_ops->state_get(handle, i, &state)) {
- dev_warn(dev, "failed to get state for domain %d\n", i);
- continue;
- }
-
pm_genpd_init(&scmi_pd->genpd, NULL,
state == SCMI_POWER_STATE_GENERIC_OFF);
+
+ domains[i] = &scmi_pd->genpd;
}

scmi_pd_data->domains = domains;
--
2.25.1