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    SubjectRe: [PATCH v10 01/11] drm/etnaviv: Add a dedicated function to register an irq handler
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    Am Samstag, dem 24.06.2023 um 23:53 +0800 schrieb Sui Jingfeng:
    > Hi,
    >
    > On 2023/6/21 18:16, Lucas Stach wrote:
    > > Am Mittwoch, dem 21.06.2023 um 17:20 +0800 schrieb Sui Jingfeng:
    > > > Hi,
    > > >
    > > > On 2023/6/21 17:07, Lucas Stach wrote:
    > > > > Am Dienstag, dem 20.06.2023 um 17:47 +0800 schrieb Sui Jingfeng:
    > > > > > From: Sui Jingfeng <suijingfeng@loongson.cn>
    > > > > >
    > > > > > Because getting IRQ from a device is platform-dependent, PCI devices have
    > > > > > different methods for getting an IRQ. This patch is a preparation to extend
    > > > > > this driver for supporting the PCI devices.
    > > > > >
    > > > > > Cc: Lucas Stach <l.stach@pengutronix.de>
    > > > > > Cc: Christian Gmeiner <christian.gmeiner@gmail.com>
    > > > > > Cc: Philipp Zabel <p.zabel@pengutronix.de>
    > > > > > Cc: Bjorn Helgaas <bhelgaas@google.com>
    > > > > > Cc: Daniel Vetter <daniel@ffwll.ch>
    > > > > > Signed-off-by: Sui Jingfeng <suijingfeng@loongson.cn>
    > > > > > ---
    > > > > > drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 32 +++++++++++++++++++--------
    > > > > > 1 file changed, 23 insertions(+), 9 deletions(-)
    > > > > >
    > > > > > diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
    > > > > > index de8c9894967c..a03e81337d8f 100644
    > > > > > --- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
    > > > > > +++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
    > > > > > @@ -1817,6 +1817,27 @@ static const struct of_device_id etnaviv_gpu_match[] = {
    > > > > > };
    > > > > > MODULE_DEVICE_TABLE(of, etnaviv_gpu_match);
    > > > > >
    > > > > > +static int etnaviv_gpu_register_irq(struct etnaviv_gpu *gpu, int irq)
    > > > > > +{
    > > > > > + struct device *dev = gpu->dev;
    > > > > > + int err;
    > > > > > +
    > > > > > + if (irq < 0)
    > > > > > + return irq;
    > > > > > +
    > > > > > + err = devm_request_irq(dev, irq, irq_handler, 0, dev_name(dev), gpu);
    > > > > > + if (err) {
    > > > > > + dev_err(dev, "failed to request irq %u: %d\n", irq, err);
    > > > > > + return err;
    > > > > > + }
    > > > > > +
    > > > > > + gpu->irq = irq;
    > > > > > +
    > > > > > + dev_info(dev, "irq(%d) handler registered\n", irq);
    > > > > There is no reason to put this into the kernel log.
    > > > I want to see the IRQ of the device when debugging,
    > > >
    > > > etnaviv actually print very less.
    > > >
    > > > This serve as a minimal signal  to us the etnaviv_gpu_register_irq()
    > > > function is successful at driver load time.
    > > >
    > > And debugging is a very different use-case than normal operation. If
    > > it's needed at all, downgrade this to dev_dbg. This isn't interesting
    > > information for a ordinary user of a system.
    > >
    > > > > It's no different
    > > > > than other resources to the driver and we don't log each one of those
    > > > > either.
    > > > >
    > > > > In fact I don't see any reason for this change in the first place.
    > > > > Effectively you are moving a single function call into a new function,
    > > > > which doesn't seem like an improvement.
    > > > This is to make the patch easy to review, each patch is only introduce a
    > > > small function,
    > > >
    > > What I'm saying is that I don't see the need to introduce this function
    > > at all. All you need to do is move platform_get_irq out into the
    > > platform device code path. The devm_request_irq can stay where it is,
    > > as the only difference between platform and PCI device is how the irq
    > > number is retrieved from the platform.
    >
    > Yes, you are right. I understand what are asking, but my point is:
    >
    >
    > This patch is paving the way for us to introduce the PCI device driver.
    >
    > All of the patches before the patch
    > v10-0006-drm-etnaviv-Add-driver-support-for-the-PCI-devic.patch
    >
    > are actually doing the preparation.
    >
    >
    > Look at the patch 0006, I achieve the goal by 128 insertions and 7
    > deletions.
    >
    > while the only 7 deletions are actually for code shading(convert the
    > static function to global function).
    >
    > There is No large area diff and NO distortion.
    >
    > The goal is adding a PCI device driver on the top of what we already have.
    >
    >
    > Before the cleanup, the etnaviv_gpu_platform_probe() function is just
    > like is a *glue*.
    >
    > Originally,  it integrate a lot of irrelevant part together.
    >
    >
    > 1.  Mapping MMIO registers make it platform-dependent;
    >
    > 2.  Calling platform_get_irq(pdev, 0) make it platform-dependent;
    >
    I get that and I'm fine with moving this out of this function. But
    that's not what you are actually doing in this patch. You are moving
    devm_request_irq out of this function, which isn't necessary, since the
    request IRQ is not platform dependent. It's the retrieval of the IRQ
    number to request (platform_get_irq/pdev->irq) which is platform
    dependent.

    Regards,
    Lucas

    > 3.  Getting Clocks by calling devm_clk_get() make it platform-dependent;
    >
    > 4.  Calling component_add() make it subsytem and framework-dependent;
    >
    >
    > All of above list item is deny us to introduce the PCI device driver
    > wrapper.
    >
    > It(sub-functional code) is not relevant to each other.
    >
    > Hence the first five patch is actually do the clean,
    >
    > for the clarify(and tidy and good looking) of the patch 6.
    >
    >
    > I will drop the printing, but keep the cleanup function there,
    >
    > Is this acceptable?
    >
    >
    > > Regards,
    > > Lucas
    > >
    > > > which is paving the way for we introducing the PCI device driver.
    > > >
    > > > Otherwise when we introducing the PCI device driver, the patch is looks
    > > > ugly,
    > > >
    > > > It is difficult to review.
    > > >
    > > > > Regards,
    > > > > Lucas
    > > > >
    > > > > > +
    > > > > > + return 0;
    > > > > > +}
    > > > > > +
    > > > > > static int etnaviv_gpu_platform_probe(struct platform_device *pdev)
    > > > > > {
    > > > > > struct device *dev = &pdev->dev;
    > > > > > @@ -1837,16 +1858,9 @@ static int etnaviv_gpu_platform_probe(struct platform_device *pdev)
    > > > > > return PTR_ERR(gpu->mmio);
    > > > > >
    > > > > > /* Get Interrupt: */
    > > > > > - gpu->irq = platform_get_irq(pdev, 0);
    > > > > > - if (gpu->irq < 0)
    > > > > > - return gpu->irq;
    > > > > > -
    > > > > > - err = devm_request_irq(&pdev->dev, gpu->irq, irq_handler, 0,
    > > > > > - dev_name(gpu->dev), gpu);
    > > > > > - if (err) {
    > > > > > - dev_err(dev, "failed to request IRQ%u: %d\n", gpu->irq, err);
    > > > > > + err = etnaviv_gpu_register_irq(gpu, platform_get_irq(pdev, 0));
    > > > > > + if (err)
    > > > > > return err;
    > > > > > - }
    > > > > >
    > > > > > /* Get Clocks: */
    > > > > > gpu->clk_reg = devm_clk_get_optional(&pdev->dev, "reg");
    >

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