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Date: Thu, 21 Dec 2023 17:45:16 +0200
From: Andy Shevchenko <andriy.shevchenko@...el.com>
To: Mark Hasemeyer <markhas@...omium.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
Tzung-Bi Shih <tzungbi@...nel.org>,
Raul Rangel <rrangel@...omium.org>,
Konrad Dybcio <konrad.dybcio@...aro.org>,
Rob Herring <robh@...nel.org>, Sudeep Holla <sudeep.holla@....com>,
Benson Leung <bleung@...omium.org>,
Bhanu Prakash Maiya <bhanumaiya@...omium.org>,
Chen-Yu Tsai <wenst@...omium.org>,
Guenter Roeck <groeck@...omium.org>, Lee Jones <lee@...nel.org>,
Prashant Malani <pmalani@...omium.org>,
Rob Barnes <robbarnes@...gle.com>,
Stephen Boyd <swboyd@...omium.org>, chrome-platform@...ts.linux.dev
Subject: Re: [PATCH v2 22/22] platform/chrome: cros_ec: Use PM subsystem to
manage wakeirq
On Wed, Dec 20, 2023 at 04:54:36PM -0700, Mark Hasemeyer wrote:
> The cros ec driver is manually managing the wake IRQ by calling
> enable_irq_wake()/disable_irq_wake() during suspend/resume.
>
> Modify the driver to use the power management subsystem to manage the
> wakeirq.
>
> Rather than assuming that the IRQ is wake capable, use the underlying
> firmware/device tree to determine whether or not to enable it as a wake
> source. Some Chromebooks rely solely on the ec_sync pin to wake the AP
> but do not specify the interrupt as wake capable in the ACPI _CRS. For
> LPC/ACPI based systems a DMI quirk is introduced listing boards whose
> firmware should not be trusted to provide correct wake capable values.
> For device tree base systems, it is not an issue as the relevant device
> tree entries have been updated and DTS is built from source for each
> ChromeOS update.
>
> The IRQ wake logic was added on an interface basis (lpc, spi, uart) as
> opposed to adding it to cros_ec.c because the i2c subsystem already
> enables the wakirq (if applicable) on our behalf.
...
> +static const struct dmi_system_id untrusted_fw_irq_wake_capable[] = {
> + {
> + .ident = "Brya",
> + .matches = {
> + DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Brya")
> + }
Leave trailing comma.
> + },
> + {
> + .ident = "Brask",
> + .matches = {
> + DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Brask")
> + }
Ditto.
It will reduce a churn in the future if adding more fields here.
> + },
> + { }
> +}
...
> +static bool cros_ec_should_force_irq_wake_capable(void)
> +{
> + return dmi_first_match(untrusted_fw_irq_wake_capable) != NULL;
' != NULL' is redundant.
> +}
...
> struct device *dev = &pdev->dev;
> + bool irq_wake = false;
Why not put this...
> struct acpi_device *adev;
> acpi_status status;
> struct cros_ec_device *ec_dev;
> + struct resource irqres;
...here?
> u8 buf[2] = {};
> int irq, ret;
...
> + irq = platform_get_irq_resource_optional(pdev, 0, &irqres);
> + if (irq > 0) {
> ec_dev->irq = irq;
> - else if (irq != -ENXIO) {
> + if (cros_ec_should_force_irq_wake_capable())
> + irq_wake = true;
> + else
> + irq_wake = irqres.flags & IORESOURCE_IRQ_WAKECAPABLE;
> + dev_dbg(dev, "IRQ: %i, wake_capable: %i\n", irq, irq_wake);
> + } else if (irq != -ENXIO) {
> dev_err(dev, "couldn't retrieve IRQ number (%d)\n", irq);
> return irq;
> }
Yeah, this is confusing now. Which one should I trust more: irq or irqres.start?
What is the point to have irqres with this duplication?
...
> - dev_err(dev, "couldn't register ec_dev (%d)\n", ret);
> + dev_err_probe(dev, ret, "couldn't register ec_dev (%d)\n", ret);
> return ret;
return dev_err_probe(...);
...
> + dev_err_probe(dev, ret, "Failed to init device for wakeup");
> + return ret;
Ditto.
...
> + if (!np)
> + return;
Why do you need this now?
I would expect either agnostic code or the very first mandatory of_*() call
will fail with the error anyway.
...
> ret = of_property_read_u32(np, "google,cros-ec-spi-msg-delay", &val);
> if (!ret)
> ec_spi->end_of_msg_delay = val;
> + if (ec_dev->irq > 0 && of_property_read_bool(np, "wakeup-source")) {
> + ec_spi->irq_wake = true;
> + dev_dbg(&spi->dev, "IRQ: %i, wake_capable: %i\n", ec_dev->irq, ec_spi->irq_wake);
> + }
if (ret)
return;
ec_spi->irq_wake = of_property_read_bool(np, "wakeup-source"));
dev_dbg(&spi->dev, "IRQ: %i, wake_capable: %s\n", ec_dev->irq, str_yes_no(ec_spi->irq_wake));
?
...
> + if (ec_spi->irq_wake) {
> + err = device_init_wakeup(dev, true);
> + if (err) {
> + dev_err_probe(dev, err, "Failed to init device for wakeup\n");
> + return err;
return dev_err_probe(...);
> + }
> + err = dev_pm_set_wake_irq(dev, ec_dev->irq);
> + if (err)
> + dev_err_probe(dev, err, "Failed to set irq(%d) for wake\n", ec_dev->irq);
Ditto.
> + }
> - return 0;
> + return err;
Unneeded change (see above how to use dev_err_probe() in an efficient way).
ret / err... Even in one file already some inconsistency...
...
> @@ -78,6 +80,7 @@ struct cros_ec_uart {
> u32 baudrate;
> u8 flowcontrol;
> u32 irq;
> + bool irq_wake;
> struct response_info response;
> };
Run `pahole` and amend respectively to avoid wasting memory.
...
> + dev_dbg(dev, "IRQ: %i, wake_capable: %i\n", ec_uart->irq, ec_uart->irq_wake);
str_yes_no() from string_choices.h?
...
> + /* Register a new cros_ec device */
> + ret = cros_ec_register(ec_dev);
> + if (ret) {
> + dev_err(dev, "Couldn't register ec_dev (%d)\n", ret);
> + return ret;
Why not dev_err_probe() here...
> + }
> +
> + if (ec_uart->irq_wake) {
> + ret = device_init_wakeup(dev, true);
> + if (ret) {
> + dev_err_probe(dev, ret, "Failed to init device for wakeup");
> + return ret;
...and here?
> + }
> + ret = dev_pm_set_wake_irq(dev, ec_uart->irq);
> + }
> + return ret;
> }
--
With Best Regards,
Andy Shevchenko
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