Hi Geert,

On Mon, Feb 15, 2021 at 7:16 AM Geert Uytterhoeven [off-list ref] wrote:

Hi Saravana,

On Fri, Feb 12, 2021 at 4:00 AM Saravana Kannan [off-list ref] wrote:

quoted

On Thu, Feb 11, 2021 at 5:00 AM Geert Uytterhoeven [off-list ref] wrote:

quoted

  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)

Rob doesn't like the proliferation of OF_POPULATED and we don't need
it anymore, so maybe work it out with him? It's a balance between some
wasted memory (struct device(s)) vs not proliferating OF_POPULATED.

quoted

quoted

  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
        https://lore.kernel.org/linux-arm-kernel/20210205133319.1921108-1-geert+renesas@glider.be/ (local)

Good to see more evidence that this series is fixing things at a more
generic level.

I spoke too soon: if CONFIG_POWER_RESET_RMOBILE=n,
booting fails again, as everything is waiting on the system controller,
which never becomes available.
Rcar-sysc doesn't suffer from this problem, cfr. above.
Perhaps because the rmobile-sysc bindings use a hierarchical instead
of a linear PM domain description, and thus consumers point to the
children of the system controller node?
Cfr. system-controller@e6180000 in arch/arm/boot/dts/r8a7740.dtsi.

Ok, I see what's going on. The problem is that the "power domain"
fwnode being registered is not the node that contains the "compatible"
property and becomes a device. So this patch[1] is not helping here.
Fix is to do something like this (to avoid using OF_POPULATED flag and
breaking reset):

diff --git a/drivers/soc/renesas/rmobile-sysc.c

b/drivers/soc/renesas/rmobile-sysc.c
index 9046b8c933cb..b7e66139ef7d 100644

--- a/drivers/soc/renesas/rmobile-sysc.c
+++ b/drivers/soc/renesas/rmobile-sysc.c

@@ -344,6 +344,7 @@ static int __init rmobile_init_pm_domains(void)
                        of_node_put(np);
                        break;
                }
+               fwnode_dev_initialized(&np->fwnode, true);
        }

        put_special_pds();

Can you give it a shot?

[1] - https://lore.kernel.org/lkml/20210205222644.2357303-8-saravanak@google.com/ (local)

quoted

quoted

      - 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>]
(show_stack+0x10/0x14)
            [<c010a49c>] (show_stack) from [<c0159534>]
(do_raw_spin_lock+0x20/0x94)
            [<c0159534>] (do_raw_spin_lock) from [<c04089d8>]
(dev_pm_get_subsys_data+0x30/0xa0)
            [<c04089d8>] (dev_pm_get_subsys_data) from [<c0413698>]
(genpd_add_device+0x34/0x1c0)
            [<c0413698>] (genpd_add_device) from [<c041389c>]
(of_genpd_add_device+0x34/0x4c)
            [<c041389c>] (of_genpd_add_device) from [<c0a1e9bc>]
(board_staging_register_device+0xf8/0x118)
            [<c0a1e9bc>] (board_staging_register_device) from

This is indeed a pre-existing problem.
of_genpd_add_device() is called before platform_device_register(),
as it needs to attach the genpd before the device is probed.
But the spinlock is only initialized when the device is registered.
This was masked before due to an unrelated wait context check failure,
which disabled any further spinlock checks, and exposed by fw_devlinks
changing probe order.
Patch sent.
"[PATCH] staging: board: Fix uninitialized spinlock when attaching genpd"
https://lore.kernel.org/r/20210215151405.2551143-1-geert+renesas@glider.be (local)

Great!

Thanks,
Saravana