[RFC PATCH v2 3/3] usb: scan multiple buses simultaneously with coroutines
Jerome Forissier
jerome.forissier at linaro.org
Tue Jan 28 14:53:58 CET 2025
On 1/28/25 12:58, Michal Simek wrote:
> Hi,
>
> út 28. 1. 2025 v 11:20 odesílatel Jerome Forissier
> <jerome.forissier at linaro.org> napsal:
>>
>> Use the coroutines framework to scan USB buses in parallel for better
>> performance. Tested on arm64 QEMU on a somewhat contrived example
>> (4 USB buses, each with one audio device, one keyboard, one mouse and
>> one tablet).
>>
>> $ make qemu_arm64_defconfig
>> $ make -j$(nproc) CROSS_COMPILE="ccache aarch64-linux-gnu-"
>> $ qemu-system-aarch64 -M virt -nographic -cpu max -bios u-boot.bin \
>> $(for i in {1..4}; do echo -device qemu-xhci,id=xhci$i \
>> -device\ usb-{audio,kbd,mouse,tablet},bus=xhci$i.0; \
>> done)
>>
>> The time spent in usb_init() is reported on the console and shows a
>> significant improvement with COROUTINES enabled.
>>
>> ** Without COROUTINES
>>
>> Bus xhci_pci: Register 8001040 NbrPorts 8
>> Starting the controller
>> USB XHCI 1.00
>> Bus xhci_pci: Register 8001040 NbrPorts 8
>> Starting the controller
>> USB XHCI 1.00
>> Bus xhci_pci: Register 8001040 NbrPorts 8
>> Starting the controller
>> USB XHCI 1.00
>> Bus xhci_pci: Register 8001040 NbrPorts 8
>> Starting the controller
>> USB XHCI 1.00
>> scanning bus xhci_pci for devices... 6 USB Device(s) found
>> scanning bus xhci_pci for devices... 6 USB Device(s) found
>> scanning bus xhci_pci for devices... 6 USB Device(s) found
>> scanning bus xhci_pci for devices... 6 USB Device(s) found
>> USB: 4 bus(es) scanned in 5873 ms
>>
>> ** With COROUTINES
>>
>> Bus xhci_pci: Register 8001040 NbrPorts 8
>> Starting the controller
>> USB XHCI 1.00
>> Bus xhci_pci: Register 8001040 NbrPorts 8
>> Starting the controller
>> USB XHCI 1.00
>> Bus xhci_pci: Register 8001040 NbrPorts 8
>> Starting the controller
>> USB XHCI 1.00
>> Bus xhci_pci: Register 8001040 NbrPorts 8
>> Starting the controller
>> USB XHCI 1.00
>> Scanning 4 USB bus(es)... done
>> Bus xhci_pci: 6 USB device(s) found
>> Bus xhci_pci: 6 USB device(s) found
>> Bus xhci_pci: 6 USB device(s) found
>> Bus xhci_pci: 6 USB device(s) found
>> USB: 4 bus(es) scanned in 2213 ms
>>
>> Signed-off-by: Jerome Forissier <jerome.forissier at linaro.org>
>> ---
>> drivers/usb/host/usb-uclass.c | 152 +++++++++++++++++++++++++++++++++-
>> 1 file changed, 149 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/usb/host/usb-uclass.c b/drivers/usb/host/usb-uclass.c
>> index bfec303e7af..3104efe7f9e 100644
>> --- a/drivers/usb/host/usb-uclass.c
>> +++ b/drivers/usb/host/usb-uclass.c
>> @@ -9,6 +9,7 @@
>> #define LOG_CATEGORY UCLASS_USB
>>
>> #include <bootdev.h>
>> +#include <coroutines.h>
>> #include <dm.h>
>> #include <errno.h>
>> #include <log.h>
>> @@ -18,6 +19,8 @@
>> #include <dm/lists.h>
>> #include <dm/uclass-internal.h>
>>
>> +#include <time.h>
>> +
>> static bool asynch_allowed;
>>
>> struct usb_uclass_priv {
>> @@ -221,6 +224,40 @@ int usb_stop(void)
>> return err;
>> }
>>
>> +static int nbus;
>> +
>> +#if CONFIG_IS_ENABLED(COROUTINES)
>> +static void usb_scan_bus(struct udevice *bus, bool recurse)
>> +{
>> + struct usb_bus_priv *priv;
>> + struct udevice *dev;
>> + int ret;
>> +
>> + priv = dev_get_uclass_priv(bus);
>> +
>> + assert(recurse); /* TODO: Support non-recusive */
>> +
>> + debug("\n");
>> + ret = usb_scan_device(bus, 0, USB_SPEED_FULL, &dev);
>> + if (ret)
>> + printf("Scanning bus %s failed, error %d\n", bus->name, ret);
>> +}
>> +
>> +static void usb_report_devices(struct uclass *uc)
>> +{
>> + struct usb_bus_priv *priv;
>> + struct udevice *bus;
>> +
>> + uclass_foreach_dev(bus, uc) {
>> + priv = dev_get_uclass_priv(bus);
>> + printf("Bus %s: ", bus->name);
>> + if (priv->next_addr == 0)
>> + printf("No USB device found\n");
>> + else
>> + printf("%d USB device(s) found\n", priv->next_addr);
>> + }
>> +}
>> +#else
>> static void usb_scan_bus(struct udevice *bus, bool recurse)
>> {
>> struct usb_bus_priv *priv;
>> @@ -240,7 +277,81 @@ static void usb_scan_bus(struct udevice *bus, bool recurse)
>> printf("No USB Device found\n");
>> else
>> printf("%d USB Device(s) found\n", priv->next_addr);
>> + nbus++;
>> }
>> +#endif
>> +
>> +#if CONFIG_IS_ENABLED(COROUTINES)
>> +extern int udelay_yield;
>> +
>> +static void usb_scan_bus_co(void)
>> +{
>> + usb_scan_bus((struct udevice *)co_get_arg(), true);
>> + co_exit();
>> +}
>> +
>> +static struct co_stack *stk;
>> +static struct co *main_co;
>> +static struct co **co;
>> +static int co_sz = 8;
>> +
>> +static int add_usb_scan_bus_co(struct udevice *bus)
>> +{
>> + if (!co) {
>> + co = malloc(co_sz * sizeof(*co));
>> + if (!co)
>> + return -ENOMEM;
>> + }
>> + if (nbus == co_sz) {
>> + struct co **nco;
>> +
>> + co_sz *= 2;
>> + nco = realloc(co, co_sz * sizeof(*co));
>> + if (!nco)
>> + return -ENOMEM;
>> + co = nco;
>> + }
>> + if (!main_co) {
>> + main_co = co_create(NULL, NULL, 0, NULL, NULL);
>> + if (!main_co)
>> + return -ENOMEM;
>> + }
>> + if (!stk) {
>> + stk = co_stack_new(32768);
>> + if (!stk)
>> + return -ENOMEM;
>> + }
>> + co[nbus] = co_create(main_co, stk, 0, usb_scan_bus_co, bus);
>> + if (!co[nbus])
>> + return -ENOMEM;
>> + nbus++;
>> + return 0;
>> +}
>> +
>> +static void usb_scan_cleanup(void)
>> +{
>> + int i;
>> +
>> + for (i = 0; i < nbus; i++) {
>> + co_destroy(co[i]);
>> + co[i] = NULL;
>> + }
>> + nbus = 0;
>> + co_destroy(main_co);
>> + main_co = NULL;
>> + co_stack_destroy(stk);
>> + stk = NULL;
>> +}
>> +#else
>> +static int add_usb_scan_bus_co(struct udevice *bus)
>> +{
>> + return 0;
>> +}
>> +
>> +static void usb_scan_cleanup(void)
>> +{
>> +}
>> +#endif
>>
>> static void remove_inactive_children(struct uclass *uc, struct udevice *bus)
>> {
>> @@ -289,6 +400,7 @@ static int usb_probe_companion(struct udevice *bus)
>>
>> int usb_init(void)
>> {
>> + unsigned long t0 = timer_get_us();
>> int controllers_initialized = 0;
>> struct usb_uclass_priv *uc_priv;
>> struct usb_bus_priv *priv;
>> @@ -355,10 +467,40 @@ int usb_init(void)
>> continue;
>>
>> priv = dev_get_uclass_priv(bus);
>> - if (!priv->companion)
>> - usb_scan_bus(bus, true);
>> + if (!priv->companion) {
>> + if (CONFIG_IS_ENABLED(COROUTINES)) {
>> + ret = add_usb_scan_bus_co(bus);
>> + if (ret)
>> + goto out;
>> + } else {
>> + usb_scan_bus(bus, true);
>> + }
>> + }
>> }
>>
>> +#if CONFIG_IS_ENABLED(COROUTINES)
>> + {
>> + bool done;
>> + int i;
>> +
>> + printf("Scanning %d USB bus(es)... ", nbus);
>> + udelay_yield = 0xCAFEDECA;
>> + do {
>> + done = true;
>> + for (i = 0; i < nbus; i++) {
>> + if (!co[i]->done) {
>> + done = false;
>> + co_resume(co[i]);
>> + }
>> + }
>> + } while (!done);
>> + udelay_yield = 0;
>> + printf("done\n");
>> +
>> + usb_report_devices(uc);
>> + }
>> +#endif
>> +
>> /*
>> * Now that the primary controllers have been scanned and have handed
>> * over any devices they do not understand to their companions, scan
>> @@ -388,7 +530,11 @@ int usb_init(void)
>> /* if we were not able to find at least one working bus, bail out */
>> if (controllers_initialized == 0)
>> printf("No USB controllers found\n");
>> -
>> +out:
>> + if (nbus)
>> + printf("USB: %d bus(es) scanned in %ld ms\n", nbus,
>> + (timer_get_us() - t0) / 1000);
>> + usb_scan_cleanup();
>> return usb_started ? 0 : -ENOENT;
>> }
>>
>> --
>> 2.43.0
>>
>
> I have tested it on kr260 which is using 2 usb interfaces and there is
> an issue with usb hub initialization.
> That board has two hubs connected over i2c and only one of them is
> initialized over i2c.
> It means there is some work which needs to happen and likely some
> locking should be in place.
Hmmmm... I was kind of expecting that :-/ Do you think the kv260 has a
similar problem? If so I can use mine to troubleshoot.
Thanks,
--
Jerome
> Thanks,
> Michal
>
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