From: <Tudor.Ambarus@microchip.com>
To: <saravanak@google.com>
Cc: <corbet@lwn.net>, <gregkh@linuxfoundation.org>,
<rafael@kernel.org>, <khilman@kernel.org>,
<ulf.hansson@linaro.org>, <len.brown@intel.com>,
<lenb@kernel.org>, <pavel@ucw.cz>, <mturquette@baylibre.com>,
<sboyd@kernel.org>, <robh+dt@kernel.org>,
<frowand.list@gmail.com>, <maz@kernel.org>, <tglx@linutronix.de>,
<linux-doc@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<linux-pm@vger.kernel.org>, <linux-clk@vger.kernel.org>,
<devicetree@vger.kernel.org>, <linux-acpi@vger.kernel.org>,
<m.szyprowski@samsung.com>, <geert@linux-m68k.org>,
<kernel-team@android.com>
Subject: Re: [PATCH v4 0/8] Make fw_devlink=on more forgiving
Date: Wed, 10 Feb 2021 10:02:43 +0000 [thread overview]
Message-ID: <3ec7ba3a-bbf6-aa5f-7800-4fc91ab199ec@microchip.com> (raw)
In-Reply-To: <CAGETcx862JPn8759tk-69WySBvokxMXJaaOVY7L6V8FLwfpV8g@mail.gmail.com>
On 2/10/21 10:54 AM, Saravana Kannan wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>
> On Wed, Feb 10, 2021 at 12:19 AM <Tudor.Ambarus@microchip.com> wrote:
>>
>> Hi, Saravana,
>>
>> On 2/6/21 12:26 AM, 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
>>>
>>> .../admin-guide/kernel-parameters.txt | 5 ++
>>> drivers/base/core.c | 58 ++++++++++++++++++-
>>> drivers/base/power/domain.c | 2 +
>>> drivers/clk/clk.c | 3 +
>>> drivers/of/property.c | 16 +++--
>>> include/linux/fwnode.h | 20 ++++++-
>>> kernel/irq/irqdomain.c | 2 +
>>> 7 files changed, 98 insertions(+), 8 deletions(-)
>>>
>>
>> Even with this patch set applied, sama5d2_xplained can not boot.
>> Patch at [1] makes sama5d2_xplained boot again. Stephen applied it
>> to clk-next.
>
> I'm glad you won't actually have any boot issues in 5.12, but the fact
> you need [1] with this series doesn't make a lot of sense to me
> because:
>
> 1. The FWNODE_FLAG_INITIALIZED flag will be set for the clock fwnode
> in question way before any consumer devices are added.
Looks like in my case FWNODE_FLAG_INITIALIZED is not set, because
drivers/clk/at91/sama5d2.c uses of_clk_add_hw_provider().
> 2. Any consumer device added after (1) will stop trying to link to the
> clock device.
>
> Are you somehow adding a consumer to the clock fwnode before (1)?
>
> Can you try this patch without your clk fix? I was trying to avoid
> looping through a list, but looks like your case might somehow need
> it?
>
I tried it, didn't solve my boot problem. The following patch makes the
sama5d2_xplained boot again, even without the patch from [1]:
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 27ff90eacb1f..9370e4dfecae 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -4594,6 +4594,8 @@ int of_clk_add_hw_provider(struct device_node *np,
if (ret < 0)
of_clk_del_provider(np);
+ fwnode_dev_initialized(&np->fwnode, true);
+
return ret;
}
EXPORT_SYMBOL_GPL(of_clk_add_hw_provider);
Cheers,
ta
> -Saravana
>
> +++ b/drivers/base/core.c
> @@ -943,6 +943,31 @@ static void device_links_missing_supplier(struct
> device *dev)
> }
> }
>
> +static int fw_devlink_check_suppliers(struct device *dev)
> +{
> + struct fwnode_link *link;
> + int ret = 0;
> +
> + if (!dev->fwnode ||fw_devlink_is_permissive())
> + return 0;
> +
> + /*
> + * Device waiting for supplier to become available is not allowed to
> + * probe.
> + */
> + mutex_lock(&fwnode_link_lock);
> + list_for_each_entry(link, &dev->fwnode->suppliers, c_hook) {
> + if (link->supplier->flags & FWNODE_FLAG_INITIALIZED)
> + continue;
> +
> + ret = -EPROBE_DEFER;
> + break;
> + }
> + mutex_unlock(&fwnode_link_lock);
> +
> + return ret;
> +}
> +
> /**
> * device_links_check_suppliers - Check presence of supplier drivers.
> * @dev: Consumer device.
> @@ -964,21 +989,13 @@ int device_links_check_suppliers(struct device *dev)
> struct device_link *link;
> int ret = 0;
>
> - /*
> - * Device waiting for supplier to become available is not allowed to
> - * probe.
> - */
> - mutex_lock(&fwnode_link_lock);
> - if (dev->fwnode && !list_empty(&dev->fwnode->suppliers) &&
> - !fw_devlink_is_permissive()) {
> + if (fw_devlink_check_suppliers(dev)) {
> dev_dbg(dev, "probe deferral - wait for supplier %pfwP\n",
> list_first_entry(&dev->fwnode->suppliers,
> struct fwnode_link,
> c_hook)->supplier);
> - mutex_unlock(&fwnode_link_lock);
> return -EPROBE_DEFER;
> }
> - mutex_unlock(&fwnode_link_lock);
>
> device_links_write_lock();
>
>
>
>>
>> Cheers,
>> ta
>>
>> [1] https://lore.kernel.org/lkml/20210203154332.470587-1-tudor.ambarus@microchip.com/
next prev parent reply other threads:[~2021-02-10 10:06 UTC|newest]
Thread overview: 55+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20210205222651eucas1p28ef87073dea33c1c5224c14aa203bec5@eucas1p2.samsung.com>
2021-02-05 22:26 ` [PATCH v4 0/8] Make fw_devlink=on more forgiving Saravana Kannan
2021-02-05 22:26 ` [PATCH v4 1/8] driver core: fw_devlink: Detect supplier devices that will never be added Saravana Kannan
2021-02-05 22:26 ` [PATCH v4 2/8] of: property: Don't add links to absent suppliers Saravana Kannan
2021-02-09 21:25 ` Rob Herring
2021-02-05 22:26 ` [PATCH v4 3/8] driver core: Add fw_devlink.strict kernel param Saravana Kannan
2021-02-05 22:26 ` [PATCH v4 4/8] of: property: Add fw_devlink support for optional properties Saravana Kannan
2021-02-09 21:33 ` Rob Herring
2021-02-09 21:54 ` Saravana Kannan
2021-02-10 8:25 ` Geert Uytterhoeven
2021-02-05 22:26 ` [PATCH v4 5/8] driver core: fw_devlink: Handle suppliers that don't use driver core Saravana Kannan
2021-02-05 22:26 ` [PATCH v4 6/8] irqdomain: Mark fwnodes when their irqdomain is added/removed Saravana Kannan
2021-02-05 22:26 ` [PATCH v4 7/8] PM: domains: Mark fwnodes when their powerdomain " Saravana Kannan
2021-02-05 22:26 ` [PATCH v4 8/8] clk: Mark fwnodes when their clock provider " Saravana Kannan
2021-02-08 15:38 ` Rob Herring
2021-02-08 23:34 ` Saravana Kannan
2021-02-10 11:44 ` [PATCH] clk: Mark fwnodes when their clock provider is added Tudor Ambarus
2021-02-10 11:44 ` Tudor Ambarus
2021-02-11 13:00 ` Greg KH
2021-02-13 0:37 ` Stephen Boyd
[not found] ` <CGME20210325133159eucas1p297b769beb681743fb32d362a86cc6e3e@eucas1p2.samsung.com>
2021-03-25 13:31 ` Marek Szyprowski
2021-03-25 15:47 ` Geert Uytterhoeven
2021-03-25 18:25 ` Nicolas Saenz Julienne
2021-03-26 18:13 ` Stephen Boyd
2021-03-26 18:29 ` Geert Uytterhoeven
2021-04-21 3:26 ` Guenter Roeck
2021-04-21 7:00 ` Saravana Kannan
2021-02-10 19:13 ` Saravana Kannan
2021-03-30 15:42 ` Guenter Roeck
2021-03-30 16:26 ` Saravana Kannan
[not found] ` <161317679292.1254594.15797939257637374295@swboyd.mtv.corp.google.com>
2021-02-14 21:15 ` [PATCH v4 8/8] clk: Mark fwnodes when their clock provider is added/removed Saravana Kannan
2021-02-06 2:45 ` [PATCH v4 0/8] Make fw_devlink=on more forgiving Saravana Kannan
2021-02-06 19:41 ` Geert Uytterhoeven
2021-02-06 20:47 ` Saravana Kannan
2021-02-08 8:40 ` Marek Szyprowski
2021-02-08 23:57 ` Saravana Kannan
2021-02-10 8:19 ` Tudor.Ambarus
2021-02-10 8:54 ` Saravana Kannan
2021-02-10 10:02 ` Tudor.Ambarus [this message]
2021-02-10 19:14 ` Saravana Kannan
2021-02-11 13:00 ` Geert Uytterhoeven
2021-02-11 13:05 ` Geert Uytterhoeven
2021-02-12 2:59 ` Saravana Kannan
2021-02-12 8:14 ` Geert Uytterhoeven
2021-02-12 20:57 ` Saravana Kannan
2021-02-15 12:38 ` Geert Uytterhoeven
2021-02-15 21:26 ` Saravana Kannan
2021-02-16 8:05 ` Geert Uytterhoeven
2021-02-16 18:48 ` Saravana Kannan
2021-02-16 20:31 ` Geert Uytterhoeven
2021-02-17 23:57 ` Saravana Kannan
2021-02-25 9:21 ` Geert Uytterhoeven
2021-02-15 15:16 ` Geert Uytterhoeven
2021-02-15 21:57 ` Saravana Kannan
2021-02-16 12:58 ` Geert Uytterhoeven
2021-02-15 11:19 ` Geert Uytterhoeven
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