On Wed, Oct 29, 2025 at 12:46:54PM -0500, Bjorn Helgaas wrote:

On Wed, Oct 29, 2025 at 05:33:31PM +0100, Thierry Reding wrote:

quoted

From: Thierry Reding <redacted>

Pass the driver-specific data via the syscore struct and use it in the
syscore ops.

Would be nice to include the "instead of global variable" part here so
the commit log includes the benefit and can stand alone even without
the subject.

Good point.

Awesome to get rid of another global variable!  More comments below.

\o/

quoted

+++ b/arch/mips/pci/pci-alchemy.c

@@ -33,6 +33,7 @@
 
 struct alchemy_pci_context {
 	struct pci_controller alchemy_pci_ctrl; /* leave as first member! */
+	struct syscore syscore;
 	void __iomem *regs;			/* ctrl base */
 	/* tools for wired entry for config space access */
 	unsigned long last_elo0;

@@ -46,12 +47,6 @@ struct alchemy_pci_context {
 	int (*board_pci_idsel)(unsigned int devsel, int assert);
 };
 
-/* for syscore_ops. There's only one PCI controller on Alchemy chips, so this
- * should suffice for now.
- */
-static struct alchemy_pci_context *__alchemy_pci_ctx;
-
-
 /* IO/MEM resources for PCI. Keep the memres in sync with fixup_bigphys_addr
  * in arch/mips/alchemy/common/setup.c
  */

@@ -306,9 +301,7 @@ static int alchemy_pci_def_idsel(unsigned int devsel, int assert)
 /* save PCI controller register contents. */
 static int alchemy_pci_suspend(void *data)
 {
-	struct alchemy_pci_context *ctx = __alchemy_pci_ctx;
-	if (!ctx)
-		return 0;
+	struct alchemy_pci_context *ctx = data;
 
 	ctx->pm[0]  = __raw_readl(ctx->regs + PCI_REG_CMEM);
 	ctx->pm[1]  = __raw_readl(ctx->regs + PCI_REG_CONFIG) & 0x0009ffff;

@@ -328,9 +321,7 @@ static int alchemy_pci_suspend(void *data)
 
 static void alchemy_pci_resume(void *data)
 {
-	struct alchemy_pci_context *ctx = __alchemy_pci_ctx;
-	if (!ctx)
-		return;
+	struct alchemy_pci_context *ctx = data;
 
 	__raw_writel(ctx->pm[0],  ctx->regs + PCI_REG_CMEM);
 	__raw_writel(ctx->pm[2],  ctx->regs + PCI_REG_B2BMASK_CCH);

@@ -359,10 +350,6 @@ static const struct syscore_ops alchemy_pci_syscore_ops = {
 	.resume = alchemy_pci_resume,
 };
 
-static struct syscore alchemy_pci_syscore = {
-	.ops = &alchemy_pci_syscore_ops,
-};
-
 static int alchemy_pci_probe(struct platform_device *pdev)
 {
 	struct alchemy_pci_platdata *pd = pdev->dev.platform_data;

@@ -480,9 +467,10 @@ static int alchemy_pci_probe(struct platform_device *pdev)
 	__raw_writel(val, ctx->regs + PCI_REG_CONFIG);
 	wmb();
 
-	__alchemy_pci_ctx = ctx;
 	platform_set_drvdata(pdev, ctx);
-	register_syscore(&alchemy_pci_syscore);
+	ctx->syscore.ops = &alchemy_pci_syscore_ops;
+	ctx->syscore.data = ctx;
+	register_syscore(&ctx->syscore);

As far as I can tell, the only use of syscore in this driver is for
suspend/resume.

This is a regular platform_device driver, so instead of syscore, I
think it should use generic power management like other PCI host
controller drivers do, something like this:

  static int alchemy_pci_suspend_noirq(struct device *dev)
  ...

  static int alchemy_pci_resume_noirq(struct device *dev)
  ...

  static DEFINE_NOIRQ_DEV_PM_OPS(alchemy_pci_pm_ops,
                                 alchemy_pci_suspend_noirq,
                                 alchemy_pci_resume_noirq);

  static struct platform_driver alchemy_pcictl_driver = {
          .probe          = alchemy_pci_probe,
          .driver = {
                  .name   = "alchemy-pci",
                  .pm     = pm_sleep_ptr(&alchemy_pci_pm_ops),
          },
  };

Here's a sample in another driver:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/pci/controller/cadence/pci-j721e.c?id=v6.17#n663

I thought so too, but then I looked at the history and saw that it was
initially regular PM ops and then fixed by using syscore in this commit:

    commit 864c6c22e9a5742b0f43c983b6c405d52817bacd
    Author: Manuel Lauss [off-list ref]
    Date:   Wed Nov 16 15:42:28 2011 +0100
    
        MIPS: Alchemy: Fix PCI PM
    
        Move PCI Controller PM to syscore_ops since the platform_driver PM methods
        are called way too late on resume and far too early on suspend (after and
        before PCI device resume/suspend).
        This also allows to simplify wired entry management a bit.
    
        Signed-off-by: Manuel Lauss [off-list ref]
        Cc: linux-mips@linux-mips.org
        Patchwork: https://patchwork.linux-mips.org/patch/3007/
        Signed-off-by: Ralf Baechle [off-list ref]

So unfortunately I don't think it'll work for this driver.

Thierry