[PATCH 04/57] media: atomisp: Move power-management over to a custom pm-domain

Hans de Goede
2023-01-23T12:53:16Z

The atomisp does not use standard PCI power-management through the
PCI config space. Instead this driver directly tells the P-Unit to
disable the ISP over the IOSF. The standard PCI subsystem pm_ops will
try to access the config space before (resume) / after (suspend) this
driver has turned the ISP on / off, resulting in the following errors:

Unable to change power state from D0 to D3hot, device inaccessible
Unable to change power state from D3cold to D0, device inaccessible

Getting logged into dmesg a whole bunch of time during boot as well as
every time the camera is used.

To avoid these errors use a custom pm_domain instead of standard driver
pm-callbacks so that all the PCI subsys suspend / resume handling is
skipped and call pci_save_state() / pci_restore_state() ourselves.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
---
.../media/atomisp/pci/atomisp_internal.h | 1 +
.../staging/media/atomisp/pci/atomisp_v4l2.c | 44 ++++++++++++++-----
2 files changed, 33 insertions(+), 12 deletions(-)

diff --git a/drivers/staging/media/atomisp/pci/atomisp_internal.h b/drivers/staging/media/atomisp/pci/atomisp_internal.h
index 675007d7d9af..fa38d91420cf 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_internal.h
+++ b/drivers/staging/media/atomisp/pci/atomisp_internal.h
@@ -210,6 +210,7 @@ struct atomisp_device {
void __iomem *base;
const struct firmware *firmware;

+ struct dev_pm_domain pm_domain;
struct pm_qos_request pm_qos;
s32 max_isr_latency;

diff --git a/drivers/staging/media/atomisp/pci/atomisp_v4l2.c b/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
index e786b81921da..e994a4a5284e 100644
--- a/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
+++ b/drivers/staging/media/atomisp/pci/atomisp_v4l2.c
@@ -19,6 +19,7 @@
*/
#include <linux/module.h>
#include <linux/pci.h>
+#include <linux/pm_domain.h>
#include <linux/pm_runtime.h>
#include <linux/pm_qos.h>
#include <linux/timer.h>
@@ -524,7 +525,7 @@ static int atomisp_save_iunit_reg(struct atomisp_device *isp)
return 0;
}

-static int __maybe_unused atomisp_restore_iunit_reg(struct atomisp_device *isp)
+static int atomisp_restore_iunit_reg(struct atomisp_device *isp)
{
struct pci_dev *pdev = to_pci_dev(isp->dev);

@@ -662,6 +663,7 @@ static void punit_ddr_dvfs_enable(bool enable)

static int atomisp_mrfld_power(struct atomisp_device *isp, bool enable)
{
+ struct pci_dev *pdev = to_pci_dev(isp->dev);
unsigned long timeout;
u32 val = enable ? MRFLD_ISPSSPM0_IUNIT_POWER_ON :
MRFLD_ISPSSPM0_IUNIT_POWER_OFF;
@@ -703,6 +705,7 @@ static int atomisp_mrfld_power(struct atomisp_device *isp, bool enable)
tmp = (tmp >> MRFLD_ISPSSPM0_ISPSSS_OFFSET) & MRFLD_ISPSSPM0_ISPSSC_MASK;
if (tmp == val) {
trace_ipu_cstate(enable);
+ pdev->current_state = enable ? PCI_D0 : PCI_D3cold;
return 0;
}

@@ -743,6 +746,7 @@ int atomisp_power_off(struct device *dev)
pci_write_config_dword(pdev, MRFLD_PCI_CSI_CONTROL, reg);

cpu_latency_qos_update_request(&isp->pm_qos, PM_QOS_DEFAULT_VALUE);
+ pci_save_state(pdev);
return atomisp_mrfld_power(isp, false);
}

@@ -756,6 +760,7 @@ int atomisp_power_on(struct device *dev)
if (ret)
return ret;

+ pci_restore_state(to_pci_dev(dev));
cpu_latency_qos_update_request(&isp->pm_qos, isp->max_isr_latency);

/*restore register values for iUnit and iUnitPHY registers*/
@@ -767,7 +772,7 @@ int atomisp_power_on(struct device *dev)
return atomisp_css_init(isp);
}

-static int __maybe_unused atomisp_suspend(struct device *dev)
+static int atomisp_suspend(struct device *dev)
{
struct atomisp_device *isp = (struct atomisp_device *)
dev_get_drvdata(dev);
@@ -790,10 +795,12 @@ static int __maybe_unused atomisp_suspend(struct device *dev)
}
spin_unlock_irqrestore(&isp->lock, flags);

+ pm_runtime_resume(dev);
+
return atomisp_power_off(dev);
}

-static int __maybe_unused atomisp_resume(struct device *dev)
+static int atomisp_resume(struct device *dev)
{
return atomisp_power_on(dev);
}
@@ -1603,6 +1610,26 @@ static int atomisp_pci_probe(struct pci_dev *pdev, const struct pci_device_id *i
/* save the iunit context only once after all the values are init'ed. */
atomisp_save_iunit_reg(isp);

+ /*
+ * The atomisp does not use standard PCI power-management through the
+ * PCI config space. Instead this driver directly tells the P-Unit to
+ * disable the ISP over the IOSF. The standard PCI subsystem pm_ops will
+ * try to access the config space before (resume) / after (suspend) this
+ * driver has turned the ISP on / off, resulting in the following errors:
+ *
+ * "Unable to change power state from D0 to D3hot, device inaccessible"
+ * "Unable to change power state from D3cold to D0, device inaccessible"
+ *
+ * To avoid these errors override the pm_domain so that all the PCI
+ * subsys suspend / resume handling is skipped.
+ */
+ isp->pm_domain.ops.runtime_suspend = atomisp_power_off;
+ isp->pm_domain.ops.runtime_resume = atomisp_power_on;
+ isp->pm_domain.ops.suspend = atomisp_suspend;
+ isp->pm_domain.ops.resume = atomisp_resume;
+
+ dev_pm_domain_set(&pdev->dev, &isp->pm_domain);
+
pm_runtime_put_noidle(&pdev->dev);
pm_runtime_allow(&pdev->dev);

@@ -1645,6 +1672,7 @@ static int atomisp_pci_probe(struct pci_dev *pdev, const struct pci_device_id *i
request_irq_fail:
hmm_cleanup();
pm_runtime_get_noresume(&pdev->dev);
+ dev_pm_domain_set(&pdev->dev, NULL);
atomisp_unregister_entities(isp);
register_entities_fail:
atomisp_uninitialize_modules(isp);
@@ -1697,6 +1725,7 @@ static void atomisp_pci_remove(struct pci_dev *pdev)

pm_runtime_forbid(&pdev->dev);
pm_runtime_get_noresume(&pdev->dev);
+ dev_pm_domain_set(&pdev->dev, NULL);
cpu_latency_qos_remove_request(&isp->pm_qos);

atomisp_msi_irq_uninit(isp);
@@ -1721,17 +1750,8 @@ static const struct pci_device_id atomisp_pci_tbl[] = {

MODULE_DEVICE_TABLE(pci, atomisp_pci_tbl);

-static const struct dev_pm_ops atomisp_pm_ops = {
- .runtime_suspend = atomisp_power_off,
- .runtime_resume = atomisp_power_on,
- .suspend = atomisp_suspend,
- .resume = atomisp_resume,
-};

static struct pci_driver atomisp_pci_driver = {
- .driver = {
- .pm = &atomisp_pm_ops,
- },
.name = "atomisp-isp2",
.id_table = atomisp_pci_tbl,
.probe = atomisp_pci_probe,
--
2.39.0