Re: [PATCH 1/2] PCI: mediatek-gen3: Stop acquiring spinlocks in {suspend,resume}_noirq

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Il 08/06/23 19:15, Bjorn Helgaas ha scritto:
On Thu, May 04, 2023 at 01:35:08PM +0200, AngeloGioacchino Del Regno wrote:
In mtk_pcie_suspend_noirq() and mtk_pcie_resume_noirq() we are,
respectively, disabling and enabling generation of interrupts and
then saving and restoring the enabled interrupts register: since
we're using noirq PM callbacks, that can be safely done without
holding any spin lock.

Tangent: it's annoying that pcie-mediatek.c and pcie-mediatek-gen3.c
use identical "mtk_pcie_suspend_noirq()" names.  That makes browsing
harder than it needs to be.  But I see that you refer to
mediatek-gen3.

+++ b/drivers/pci/controller/pcie-mediatek-gen3.c
@@ -963,8 +963,6 @@ static void mtk_pcie_irq_save(struct mtk_gen3_pcie *pcie)
  {
  	int i;
- raw_spin_lock(&pcie->irq_lock);
-
  	pcie->saved_irq_state = readl_relaxed(pcie->base + PCIE_INT_ENABLE_REG);
for (i = 0; i < PCIE_MSI_SET_NUM; i++) {
@@ -973,16 +971,12 @@ static void mtk_pcie_irq_save(struct mtk_gen3_pcie *pcie)
  		msi_set->saved_irq_state = readl_relaxed(msi_set->base +
  					   PCIE_MSI_SET_ENABLE_OFFSET);
  	}
-
-	raw_spin_unlock(&pcie->irq_lock);
  }

Jianjun added mtk_pcie_irq_save() and mtk_pcie_irq_restore() with
d537dc125f07 ("PCI: mediatek-gen3: Add system PM support").

I suggest looking at other drivers and structuring mediatek-gen3
similarly, including using similar function names.  No other drivers
have a .*_pcie_irq_save() function.  Several have .*_pcie_host_init(),
and some of those do include some IRQ setup.

Bjorn

Hello Bjorn,
thanks for the feedback!

Yes, I of course refer to the Gen3 driver... I'll check other drivers and
will try to improve the consistency of this one with the others as soon as
I have some bandwidth to perform the job.

Thanks again,
Angelo



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