Messages in this thread | | | Subject | Re: [PATCH 09/12] usb: roles: Add Intel XHCI USB role switch driver | From | Hans de Goede <> | Date | Sun, 25 Feb 2018 14:29:25 +0100 |
| |
Hi,
On 16-02-18 14:47, Andy Shevchenko wrote: > On Fri, Feb 16, 2018 at 12:47 PM, Hans de Goede <hdegoede@redhat.com> wrote: >> Various Intel SoCs (Cherry Trail, Broxton and others) have an internal USB >> role switch for swiching the OTG USB data lines between the xHCI host >> controller and the dwc3 gadget controller. >> >> Note on some Cherry Trail systems there is ACPI/AML code listening to >> edge interrupts on the id-pin (through an _AIE ACPI method) and switching >> the role between ROLE_HOST and ROLE_NONE based on the id-pin. Note it does >> not set the role to ROLE_DEVICE, because device-mode is usually not used >> under Windows. >> >> The presence of AML code which modifies the cfg0 reg (on some systems) >> means that we our read/write/modify of cfg0 may race with the AML code >> doing the same to avoid this we take the global ACPI lock while doing >> the read/write/modify. > >> +/* register definition */ >> +#define DUAL_ROLE_CFG0 0x68 >> +#define SW_VBUS_VALID (1 << 24) >> +#define SW_IDPIN_EN (1 << 21) >> +#define SW_IDPIN (1 << 20) >> + >> +#define DUAL_ROLE_CFG1 0x6c >> +#define HOST_MODE (1 << 29) > > Does it make sense to use BIT() macro above?
Yes, fixed for v2.
> > >> +struct intel_xhci_acpi_match { >> + const char *hid; >> + int hrv; >> +}; > > Consider to unify with struct acpi_ac_bl.
That is not a bad idea, but probably best done as a follow-up commit, since this patch-set already touches enough subsystems as is.
I just added this to my TODO: -Add acpi_find_dev_present() helprt which takes an array of and returns a pointer to (or NULL): struct acpi_dev_present_match { const char *hid; const char *uid; int hrv; }; And use this in drivers/acpi/ac.c drivers/acpi/battery.c, drivers/usb/roles/intel-xhci-usb-role-switch.c, ...
>> +static const struct intel_xhci_acpi_match allow_userspace_ctrl_ids[] = { >> + { "INT33F4", 3 }, /* X-Powers AXP288 PMIC */ >> +}; >> + >> +static int intel_xhci_usb_set_role(struct device *dev, enum usb_role role) >> +{ >> + struct intel_xhci_usb_data *data = dev_get_drvdata(dev); >> + unsigned long timeout; >> + acpi_status status; > >> + u32 glk = -1U; > > I prefer to see consistency and moreover less confusing set, like > > ~0U
Looks like a chose a bad example as user of the acpi_acquire_global_lock() function, others don't init this at all because it is not necessary.
> >> + u32 val; >> + >> + /* >> + * On many CHT devices ACPI event (_AEI) handlers read / modify / >> + * write the cfg0 register, just like we do. Take the ACPI lock >> + * to avoid us racing with the AML code. >> + */ >> + status = acpi_acquire_global_lock(ACPI_WAIT_FOREVER, &glk); > > FOREVER?! > Wouldn't be slightly long under certain circumstances?
The mode-switch itself may take up-to 600ms, so I don't think any delays caused by this will be a problem. This is just some weird ACPI-subsys-ism where instead of just having a mutex and using mutex_trylock() where necessary, the ACPICA code has its own private timeout handling. I'm sure if I were to just do a mutex_lock() here nobody would fall over that. The FOREVER just makes this look scarier then it really is, in theory any mutex_lock() call can wait forever.
>> + if (ACPI_FAILURE(status) && status != AE_NOT_CONFIGURED) { >> + dev_err(dev, "Error could not acquire lock\n"); >> + return -EIO; >> + } > >> + acpi_release_global_lock(glk); > >> + /* Polling on CFG1 register to confirm mode switch.*/ >> + do { >> + val = readl(data->base + DUAL_ROLE_CFG1); > >> + if (!!(val & HOST_MODE) == (role == USB_ROLE_HOST)) > > I would prefer ^ instead of first ==, but it's up to you. > >> + return 0; >> + >> + /* Interval for polling is set to about 5 - 10 ms */ >> + usleep_range(5000, 10000); >> + } while (time_before(jiffies, timeout)); >> + >> + dev_warn(dev, "Timeout waiting for role-switch\n"); >> + return -ETIMEDOUT; >> +} > >> +static int intel_xhci_usb_probe(struct platform_device *pdev) >> +{ >> + struct device *dev = &pdev->dev; >> + struct intel_xhci_usb_data *data; >> + struct resource *res; >> + resource_size_t size; >> + int i, ret; >> + >> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > >> + size = (res->end + 1) - res->start; > > resource_size()
Fixed for v2.
>> + data->base = devm_ioremap_nocache(dev, res->start, size); > > So, what's wrong with devm_ioremap_resource() ? > ...which also prints an error message.
Nothing, I inherited this from the Android X86 patches this is based on, fixed for v2.
> >> + if (IS_ERR(data->base)) { >> + ret = PTR_ERR(data->base); > >> + dev_err(dev, "Error iomaping registers: %d\n", ret); > > At least printing return code is useless. Driver core does this. > >> + return ret; >> + } >> + > >> + data->role_sw = usb_role_switch_register(dev, &sw_desc); >> + if (IS_ERR(data->role_sw)) { >> + ret = PTR_ERR(data->role_sw); > >> + dev_err(dev, "Error registering role-switch: %d\n", ret); > > Ditto.
Ok, both dropped.
> >> + return ret; >> + } >> + >> + return 0; >> +} > >> +static const struct platform_device_id intel_xhci_usb_table[] = { >> + { .name = DRV_NAME }, > >> + {}, > > No comma, please.
Fixed for v2.
Regards,
Hans
| |