Re: [PATCH v3 15/15] xhci: tegra: Enable ELPG for runtime/system PM

JC Kuo
2020-10-15T08:12:46Z

I will amend accordingly and submit new patch.

Thanks for review.
JC

On 9/28/20 10:06 PM, Thierry Reding wrote:
> On Wed, Sep 09, 2020 at 04:10:41PM +0800, JC Kuo wrote:
>> This commit implements the complete programming sequence for ELPG
>> entry and exit.
>>
>> 1. At ELPG entry, invokes tegra_xusb_padctl_enable_phy_sleepwalk()
>> and tegra_xusb_padctl_enable_phy_wake() to configure XUSB PADCTL
>> sleepwalk and wake detection circuits to maintain USB lines level
>> and respond to wake events (wake-on-connect, wake-on-disconnect,
>> device-initiated-wake).
>>
>> 2. At ELPG exit, invokes tegra_xusb_padctl_disable_phy_sleepwalk()
>> and tegra_xusb_padctl_disable_phy_wake() to disarm sleepwalk and
>> wake detection circuits.
>>
>> At runtime suspend, XUSB host controller can enter ELPG to reduce
>> power consumption. When XUSB PADCTL wake detection circuit detects
>> a wake event, an interrupt will be raised. xhci-tegra driver then
>> will invoke pm_runtime_resume() for xhci-tegra.
>>
>> Runtime resume could also be triggered by protocol drivers, this is
>> the host-initiated-wake event. At runtime resume, xhci-tegra driver
>> brings XUSB host controller out of ELPG to handle the wake events.
>>
>> The same ELPG enter/exit procedure will be performed for system
>> suspend/resume path so USB devices can remain connected across SC7.
>>
>> Signed-off-by: JC Kuo <jckuo@nvidia.com>
>> ---
>> v3:
>> use 'unsigned int' for PHY index
>> remove unnecessary 'else'
>> drop IRQF_TRIGGER_HIGH when invokes devm_request_threaded_irq()
>>
>> drivers/usb/host/xhci-tegra.c | 389 +++++++++++++++++++++++++++++++---
>> 1 file changed, 360 insertions(+), 29 deletions(-)
>>
>> diff --git a/drivers/usb/host/xhci-tegra.c b/drivers/usb/host/xhci-tegra.c
>> index aabff8ee0bb3..ba3f40e78171 100644
>> --- a/drivers/usb/host/xhci-tegra.c
>> +++ b/drivers/usb/host/xhci-tegra.c
>> @@ -15,9 +15,11 @@
>> #include <linux/kernel.h>
>> #include <linux/module.h>
>> #include <linux/of_device.h>
>> +#include <linux/of_irq.h>
>> #include <linux/phy/phy.h>
>> #include <linux/phy/tegra/xusb.h>
>> #include <linux/platform_device.h>
>> +#include <linux/usb/ch9.h>
>> #include <linux/pm.h>
>> #include <linux/pm_domain.h>
>> #include <linux/pm_runtime.h>
>> @@ -224,6 +226,7 @@ struct tegra_xusb {
>>
>> int xhci_irq;
>> int mbox_irq;
>> + int padctl_irq;
>>
>> void __iomem *ipfs_base;
>> void __iomem *fpci_base;
>> @@ -269,10 +272,13 @@ struct tegra_xusb {
>> dma_addr_t phys;
>> } fw;
>>
>> + bool suspended;
>> struct tegra_xusb_context context;
>> };
>>
>> static struct hc_driver __read_mostly tegra_xhci_hc_driver;
>> +static int tegra_xusb_exit_elpg(struct tegra_xusb *tegra, bool runtime);
>> +static int tegra_xusb_enter_elpg(struct tegra_xusb *tegra, bool runtime);
>
> Can we reshuffle the code to avoid these predeclarations? Looks like
> they're only used in tegra_xusb_runtime_{suspend,resume}(), so perhaps
> move the implementations right before those?
>
> Thierry
>