[PATCH v2] firewire: ohci: convert to generic power management

From: Bjorn Helgaas
Date: Tue Oct 25 2022 - 17:25:43 EST


From: Vaibhav Gupta <vaibhavgupta40@xxxxxxxxx>

Convert ohci from legacy PCI power management to the generic power
management framework.

Previously, ohci used legacy PCI power management, and pci_suspend() and
pci_resume() were responsible for both device-specific things and generic
PCI things:

pci_suspend
software_reset() <-- device-specific
pci_save_state(pdev) <-- generic PCI
pci_set_power_state(pdev, pci_choose_state(pdev, state)) <-- generic PCI
pmac_ohci_off(pdev) <-- device-specific

pci_resume
pmac_ohci_on(pdev) <-- device-specific
pci_set_power_state(pdev, PCI_D0) <-- generic PCI
pci_restore_state(pdev) <-- generic PCI
ohci_enable() <-- device-specific
...

With generic power management, the PCI bus PM methods do the generic PCI
things, and the driver needs only the device-specific part, i.e.,

suspend_devices_and_enter
dpm_suspend_start(PMSG_SUSPEND)
pci_pm_suspend # PCI bus .suspend() method
pci_suspend # dev->driver->pm->suspend
software_reset() <-- device-specific
pmac_ohci_off(pdev) <-- device-specific (DIFFERENT ORDER)
suspend_enter
dpm_suspend_noirq(PMSG_SUSPEND)
pci_pm_suspend_noirq # PCI bus .suspend_noirq() method
pci_save_state <-- generic PCI
pci_prepare_to_sleep <-- generic PCI
pci_set_power_state
...
dpm_resume_end(PMSG_RESUME)
pci_pm_resume # PCI bus .resume() method
pci_restore_standard_config
pci_set_power_state(PCI_D0) <-- generic PCI
pci_restore_state <-- generic PCI
pci_resume # dev->driver->pm->resume
pmac_ohci_on(pdev) <-- device-specific (DIFFERENT ORDER)
ohci_enable() <-- device-specific
...

N.B. This changes the order of pmac_ohci_off() and pmac_ohci_on().
Previously, pmac_ohci_off() was called *after* pci_save_state() and
pci_set_power_state(), and this change calls it *before*.

Similarly, pmac_ohci_on() was previously called *before*
pci_set_power_state() and pci_restore_state() and this change calls it
*after*.

The code in pmac_ohci_on() and pmac_ohci_off() was added by ea8d006b91ac
("firewire: fw-ohci: PPC PMac platform code").

Signed-off-by: Vaibhav Gupta <vaibhavgupta40@xxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
---

v1 was posted at https://lore.kernel.org/r/20200720150715.624520-1-vaibhavgupta40@xxxxxxxxx

Changes from v1 to v2:
- Convert from SIMPLE_DEV_PM_OPS() (which is deprecated) to
DEFINE_SIMPLE_DEV_PM_OPS() and remove __maybe_unused annotations.
- Expand commit log.

drivers/firewire/ohci.c | 41 +++++++++++------------------------------
1 file changed, 11 insertions(+), 30 deletions(-)

diff --git a/drivers/firewire/ohci.c b/drivers/firewire/ohci.c
index 17c9d825188b..f3cceca51e59 100644
--- a/drivers/firewire/ohci.c
+++ b/drivers/firewire/ohci.c
@@ -3165,7 +3165,6 @@ static int ohci_set_iso_channels(struct fw_iso_context *base, u64 *channels)
return ret;
}

-#ifdef CONFIG_PM
static void ohci_resume_iso_dma(struct fw_ohci *ohci)
{
int i;
@@ -3183,7 +3182,6 @@ static void ohci_resume_iso_dma(struct fw_ohci *ohci)
ohci_start_iso(&ctx->base, 0, ctx->sync, ctx->tags);
}
}
-#endif

static int queue_iso_transmit(struct iso_context *ctx,
struct fw_iso_packet *packet,
@@ -3789,39 +3787,24 @@ static void pci_remove(struct pci_dev *dev)
dev_notice(&dev->dev, "removed fw-ohci device\n");
}

-#ifdef CONFIG_PM
-static int pci_suspend(struct pci_dev *dev, pm_message_t state)
+static int pci_suspend(struct device *dev)
{
- struct fw_ohci *ohci = pci_get_drvdata(dev);
- int err;
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct fw_ohci *ohci = pci_get_drvdata(pdev);

software_reset(ohci);
- err = pci_save_state(dev);
- if (err) {
- ohci_err(ohci, "pci_save_state failed\n");
- return err;
- }
- err = pci_set_power_state(dev, pci_choose_state(dev, state));
- if (err)
- ohci_err(ohci, "pci_set_power_state failed with %d\n", err);
- pmac_ohci_off(dev);
+ pmac_ohci_off(pdev);

return 0;
}

-static int pci_resume(struct pci_dev *dev)
+static int pci_resume(struct device *dev)
{
- struct fw_ohci *ohci = pci_get_drvdata(dev);
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct fw_ohci *ohci = pci_get_drvdata(pdev);
int err;

- pmac_ohci_on(dev);
- pci_set_power_state(dev, PCI_D0);
- pci_restore_state(dev);
- err = pci_enable_device(dev);
- if (err) {
- ohci_err(ohci, "pci_enable_device failed\n");
- return err;
- }
+ pmac_ohci_on(pdev);

/* Some systems don't setup GUID register on resume from ram */
if (!reg_read(ohci, OHCI1394_GUIDLo) &&
@@ -3838,7 +3821,6 @@ static int pci_resume(struct pci_dev *dev)

return 0;
}
-#endif

static const struct pci_device_id pci_table[] = {
{ PCI_DEVICE_CLASS(PCI_CLASS_SERIAL_FIREWIRE_OHCI, ~0) },
@@ -3847,15 +3829,14 @@ static const struct pci_device_id pci_table[] = {

MODULE_DEVICE_TABLE(pci, pci_table);

+static DEFINE_SIMPLE_DEV_PM_OPS(pci_pm_ops, pci_suspend, pci_resume);
+
static struct pci_driver fw_ohci_pci_driver = {
.name = ohci_driver_name,
.id_table = pci_table,
.probe = pci_probe,
.remove = pci_remove,
-#ifdef CONFIG_PM
- .resume = pci_resume,
- .suspend = pci_suspend,
-#endif
+ .driver.pm = &pci_pm_ops,
};

static int __init fw_ohci_init(void)
--
2.25.1