第16章　USB主机、设备与Gadget驱动之USB UDC与Gadget驱动（二）

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最新推荐文章于 2024-07-14 00:15:00 发布 · 4.1k 阅读

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16.4.2　Chipidea（公司） USB UDC（USB设备控制器）驱动

Chipidea USB UDC驱动的主体代码路径：drivers/usb/chipidea/udc.c，代码清单16.33列出其初始化流程部分，并定义了usb_ep_ops、usb_gadget_ops，在最终进行usb_add_gadget_udc（）之前填充好了UDC的端点列表。

代码清单16.33　Chipidea USB UDC驱动实例

/**
* Endpoint-specific part of the API to the USB controller hardware
* Check "usb_gadget.h" for details
*/
static const struct usb_ep_ops usb_ep_ops = {
.enable = ep_enable,
.disable = ep_disable,
.alloc_request = ep_alloc_request,
.free_request = ep_free_request,
.queue = ep_queue,
.dequeue = ep_dequeue,
.set_halt = ep_set_halt,
.set_wedge = ep_set_wedge,
.fifo_flush = ep_fifo_flush,

};

/**
* Device operations part of the API to the USB controller hardware,
* which don't involve endpoints (or i/o)
* Check "usb_gadget.h" for details
*/
static const struct usb_gadget_ops usb_gadget_ops = {
.vbus_session = ci_udc_vbus_session,
.wakeup = ci_udc_wakeup,
.pullup = ci_udc_pullup,
.vbus_draw = ci_udc_vbus_draw,
.udc_start = ci_udc_start,
.udc_stop = ci_udc_stop,

};

static int init_eps(struct ci_hdrc *ci)
{
int retval = 0, i, j;

for (i = 0; i < ci->hw_ep_max/2; i++)
for (j = RX; j <= TX; j++) {
int k = i + j * ci->hw_ep_max/2;
struct ci_hw_ep *hwep = &ci->ci_hw_ep[k];

scnprintf(hwep->name, sizeof(hwep->name), "ep%i%s", i, (j == TX) ? "in" : "out");
hwep->ci = ci;
hwep->lock = &ci->lock;
hwep->td_pool = ci->td_pool;
hwep->ep.name = hwep->name;
hwep->ep.ops = &usb_ep_ops;
/*
* for ep0: maxP defined in desc, for other
* eps, maxP is set by epautoconfig() called
* by gadget layer
*/
usb_ep_set_maxpacket_limit(&hwep->ep, (unsigned short)~0);
INIT_LIST_HEAD(&hwep->qh.queue);
hwep->qh.ptr = dma_pool_alloc(ci->qh_pool, GFP_KERNEL, &hwep->qh.dma);
if (hwep->qh.ptr == NULL)
retval = -ENOMEM;
else
memset(hwep->qh.ptr, 0, sizeof(*hwep->qh.ptr));

/*
* set up shorthands for ep0 out and in endpoints,