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SubjectRe: [PATCH v4 0/8] Make fw_devlink=on more forgiving
Hi Saravana,

On Fri, Feb 5, 2021 at 11:26 PM Saravana Kannan <> wrote:
> There are a lot of devices/drivers where they never have a struct device
> created for them or the driver initializes the hardware without ever
> binding to the struct device.
> This series is intended to avoid any boot regressions due to such
> devices/drivers when fw_devlink=on and also address the handling of
> optional suppliers.
> Patch 1 and 2 addresses the issue of firmware nodes that look like
> they'll have struct devices created for them, but will never actually
> have struct devices added for them. For example, DT nodes with a
> compatible property that don't have devices added for them.
> Patch 3 and 4 allow for handling optional DT bindings.
> Patch 5 sets up a generic API to handle drivers that never bind with
> their devices.
> Patch 6 through 8 update different frameworks to use the new API.
> Thanks,
> Saravana
> Saravana Kannan (8):
> driver core: fw_devlink: Detect supplier devices that will never be
> added
> of: property: Don't add links to absent suppliers
> driver core: Add fw_devlink.strict kernel param
> of: property: Add fw_devlink support for optional properties
> driver core: fw_devlink: Handle suppliers that don't use driver core
> irqdomain: Mark fwnodes when their irqdomain is added/removed
> PM: domains: Mark fwnodes when their powerdomain is added/removed
> clk: Mark fwnodes when their clock provider is added/removed

Thanks for your series, which is now part of driver-core-next.
I gave driver-core-next + [1] a try on various Renesas boards.
Test results are below.
In general, the result looks much better than before.

[1] -

1. R-Car Gen2 (Koelsch), R-Car Gen3 (Salvator-X(S), Ebisu).

- Commit 2dfc564bda4a31bc ("soc: renesas: rcar-sysc: Mark device
node OF_POPULATED after init") is no longer needed (but already
queued for v5.12 anyway)

- Some devices are reprobed, despite their drivers returning
a real error code, and not -EPROBE_DEFER:

renesas_wdt e6020000.watchdog: Watchdog blacklisted on r8a7791 ES1.*
(rwdt_probe() returns -ENODEV)

sh-pfc e6060000.pinctrl: pin GP_7_23 already requested by
ee090000.pci; cannot claim for e6590000.usb
sh-pfc e6060000.pinctrl: pin-247 (e6590000.usb) status -22
sh-pfc e6060000.pinctrl: could not request pin 247
(GP_7_23) from group usb0 on device sh-pfc
renesas_usbhs e6590000.usb: Error applying setting,
reverse things back
renesas_usbhs: probe of e6590000.usb failed with error -22

rcar-pcie fe000000.pcie: host bridge /soc/pcie@fe000000 ranges:
rcar-pcie fe000000.pcie: IO
0x00fe100000..0x00fe1fffff -> 0x0000000000
rcar-pcie fe000000.pcie: MEM
0x00fe200000..0x00fe3fffff -> 0x00fe200000
rcar-pcie fe000000.pcie: MEM
0x0030000000..0x0037ffffff -> 0x0030000000
rcar-pcie fe000000.pcie: MEM
0x0038000000..0x003fffffff -> 0x0038000000
rcar-pcie fe000000.pcie: IB MEM
0x0040000000..0x00bfffffff -> 0x0040000000
rcar-pcie fe000000.pcie: IB MEM
0x0200000000..0x02ffffffff -> 0x0200000000
rcar-pcie fe000000.pcie: PCIe link down
(rcar_pcie_probe() returns -ENODEV)

xhci-hcd ee000000.usb: xHCI Host Controller
xhci-hcd ee000000.usb: new USB bus registered, assigned bus number 7
xhci-hcd ee000000.usb: Direct firmware load for
r8a779x_usb3_v3.dlmem failed with error -2
xhci-hcd ee000000.usb: can't setup: -2
xhci-hcd ee000000.usb: USB bus 7 deregistered
xhci-hcd: probe of ee000000.usb failed with error -2

- The PCI reprobing leads to a memory leak, for which I've sent a fix
"[PATCH] PCI: Fix memory leak in pci_register_io_range()"

- I2C on R-Car Gen3 does not seem to use DMA, according to

-dma4chan0 | e66d8000.i2c:tx
-dma4chan1 | e66d8000.i2c:rx
-dma5chan0 | e6510000.i2c:tx

- Disabling CONFIG_IPMMU_VMSA (IOMMU) now works, good!

ignoring dependency for device, assuming no driver

- Disabling CONFIG_RCAR_DMAC works for most devices, except for

-rcar_sound ec500000.sound: probed

ALSA device list:
- #0: rcar-sound
+ No soundcards found.

# cat /sys/kernel/debug/devices_deferred

platform e6510000.i2c: Linked as a sync state only
consumer to ec500000.sound
platform ec500000.sound: Linked as a consumer to e6060000.pinctrl
platform ec500000.sound: Linked as a consumer to
i2c 2-0010: Linked as a consumer to ec500000.sound
platform ec500000.sound: Linked as a consumer to 2-004f
cs2000-cp 2-004f: revision - C1
i2c-rcar e6510000.i2c: probed
i2c-rcar e6510000.i2c: Dropping the link to ec500000.sound
i2c 2-0010: probe deferral - supplier ec500000.sound not ready

With CONFIG_RCAR_DMAC=y, ec500000.sound is probed quite early.


ak4613: codec@10 {
clocks = <&rcar_sound 3>;

port {
ak4613_endpoint: endpoint {
remote-endpoint = <&rsnd_endpoint0>;

sound_card: sound {
dais = <&rsnd_port0 /* ak4613 */
&rsnd_port1 /* HDMI0 */
&rsnd_port2>; /* HDMI1 */

rcar_sound: sound@ec500000 {
ports {
rsnd_port0: port@0 {
rsnd_endpoint0: endpoint {
remote-endpoint =

2. SH/R-Mobile AG5 (kzm9g), APE6 (ape6evm), A1 (armadillo800-eva)

- "PATCH] soc: renesas: rmobile-sysc: Set OF_POPULATED and absorb
reset handling" is no longer needed

- On R-Mobile A1, I get a BUG and a memory leak:

BUG: spinlock bad magic on CPU#0, swapper/1
lock: lcdc0_device+0x10c/0x308, .magic: 00000000, .owner:
<none>/-1, .owner_cpu: 0
CPU: 0 PID: 1 Comm: swapper Not tainted
5.11.0-rc5-armadillo-00032-gf0a85c26907e #266
Hardware name: Generic R8A7740 (Flattened Device Tree)
[<c010c3c8>] (unwind_backtrace) from [<c010a49c>]
[<c010a49c>] (show_stack) from [<c0159534>]
[<c0159534>] (do_raw_spin_lock) from [<c04089d8>]
[<c04089d8>] (dev_pm_get_subsys_data) from [<c0413698>]
[<c0413698>] (genpd_add_device) from [<c041389c>]
[<c041389c>] (of_genpd_add_device) from [<c0a1e9bc>]
[<c0a1e9bc>] (board_staging_register_device) from
[<c0a1ea00>] (board_staging_register_devices+0x24/0x28)
[<c0a1ea00>] (board_staging_register_devices) from
[<c0a1ea30>] (runtime_board_check+0x2c/0x40)
[<c0a1ea30>] (runtime_board_check) from [<c0101fac>]
[<c0101fac>] (do_one_initcall) from [<c0a01034>]
[<c0a01034>] (kernel_init_freeable) from [<c05fd568>]
[<c05fd568>] (kernel_init) from [<c010011c>]
Exception stack(0xc19c9fb0 to 0xc19c9ff8)
9fa0: 00000000
00000000 00000000 00000000
9fc0: 00000000 00000000 00000000 00000000 00000000
00000000 00000000 00000000
9fe0: 00000000 00000000 00000000 00000000 00000013 00000000

unreferenced object 0xc4134e00 (size 512):
comm "swapper", pid 1, jiffies 4294937296 (age 3541.930s)
hex dump (first 32 bytes):
00 4e 13 c4 00 4e 13 c4 ff ff ff 7f ff ff ff 7f
ff ff ff 7f 02 00 00 00 00 5f 13 c4 1c 4e 13 c4
[<de1a3c34>] dev_pm_qos_constraints_allocate+0x10/0xcc
[<d21cf6e4>] dev_pm_qos_add_notifier+0x6c/0xd0
[<e04bbc90>] genpd_add_device+0x178/0x1c0
[<95067303>] of_genpd_add_device+0x34/0x4c
[<c334b97a>] board_staging_register_device+0xf8/0x118
[<01bd495a>] board_staging_register_devices+0x24/0x28
[<fb25a5d8>] runtime_board_check+0x2c/0x40
[<65aed679>] do_one_initcall+0xe0/0x278
[<97e3f4f7>] kernel_init_freeable+0x174/0x1c0
[<63c8fed0>] kernel_init+0x8/0x118
[<f704d96c>] ret_from_fork+0x14/0x38
[<00000000>] 0x0

3. RZ/A1 and RZ/A2: No issues.



Geert Uytterhoeven -- There's lots of Linux beyond ia32 --

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds

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