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Message-ID: <56A90971.4020409@ti.com>
Date: Wed, 27 Jan 2016 12:16:17 -0600
From: Suman Anna <s-anna@...com>
To: Tony Lindgren <tony@...mide.com>,
Kishon Vijay Abraham I <kishon@...com>
CC: Bjorn Helgaas <bhelgaas@...gle.com>, <richardcochran@...il.com>,
Russell King <linux@....linux.org.uk>,
<linux-omap@...r.kernel.org>,
<linux-arm-kernel@...ts.infradead.org>,
<linux-kernel@...r.kernel.org>, <nsekhar@...com>
Subject: Re: [PATCH v3 3/3] pci: dra7xx: use pdata callbacks to perform reset
Hi Tony,
On 01/27/2016 11:31 AM, Tony Lindgren wrote:
> * Kishon Vijay Abraham I <kishon@...com> [160114 06:12]:
>> 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.
> ...
>
>> --- 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?
>
>> @@ -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
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