Hi Tony,

On 01/27/2016 11:31 AM, Tony Lindgren wrote:

* Kishon Vijay Abraham I [off-list ref] [160114 06:12]:

quoted

Use assert/deassert callbacks populated in the platform data to
to perform reset of PCIe.

Use these callbacks until a reset controller driver is
is available in the kernel to reset PCIe.

...

quoted

--- a/drivers/pci/host/pci-dra7xx.c
+++ b/drivers/pci/host/pci-dra7xx.c

@@ -347,6 +404,10 @@ static int __init dra7xx_pcie_probe(struct platform_device *pdev)
 	enum of_gpio_flags flags;
 	unsigned long gpio_flags;
 
+	ret = dra7xx_pcie_reset(pdev);
+	if (ret)
+		return ret;
+
 	dra7xx = devm_kzalloc(dev, sizeof(*dra7xx), GFP_KERNEL);
 	if (!dra7xx)
 		return -ENOMEM;

With the hwmod data properly configured the reset already happens
for the device by the bus driver, the hwmod code in this case?

quoted

@@ -457,6 +518,7 @@ static int __exit dra7xx_pcie_remove(struct platform_device *pdev)
 	struct pcie_port *pp = &dra7xx->pp;
 	struct device *dev = &pdev->dev;
 	int count = dra7xx->phy_count;
+	int ret;
 
 	if (pp->irq_domain)
 		irq_domain_remove(pp->irq_domain);

@@ -467,6 +529,10 @@ static int __exit dra7xx_pcie_remove(struct platform_device *pdev)
 		phy_exit(dra7xx->phy[count]);
 	}
 
+	ret = dra7xx_pcie_assert_reset(pdev);
+	if (ret < 0)
+		return ret;
+
 	return 0;
 }

Why do you need another reset here? Can't you just implement PM runtime
in the driver and do the usual pm_runtime_put_sync followed by
pm_runtime_disable?

The omap_hwmod_enable/disable code does not deal with hardresets (PRCM
reset lines) and so the pm_runtime_get_sync/put_sync only end up dealing
with clocks, and we need to invoke the reset functions separately.
Modules with softresets in SYSCONFIG are ok, as they are dealt with
properly.

Basically I'm wondering how come we need these platform data callbacks
at all.

The hardresets are controlled through the
omap_device_assert(deassert)_hardreset functions, and since these are
limited to mach-omap2, we are invoking them through platform data callbacks.


regards
Suman