Initial commit: Schunix as it stands before the SchOS rename
An x86-64 operating system built from xv6, now largely rewritten: SMP, a copy-on-write root filesystem (SchFS), PCI/USB/virtio drivers, a TTF rasteriser, and a Linux-numbered syscall ABI. No history before this point -- the tree was never under version control. This commit exists so the rename that follows has something to undo to.
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Nexoniarz
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185
kernel/drivers/usb/hub/usb_hub.c
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185
kernel/drivers/usb/hub/usb_hub.c
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// USB hub class driver.
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//
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// A hub is what makes USB a tree rather than a handful of sockets, and
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// nothing about driving one is special: every operation is an ordinary
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// control request sent to the hub as a device. "Reset port 3" is a
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// SET_FEATURE(PORT_RESET, wIndex=3). The hub has an interrupt endpoint too,
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// which reports which ports have changed, but that is only needed for
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// hotplug -- at boot it is enough to walk every port and look.
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//
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// What *is* special is what the host controller has to be told. xHCI does not
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// discover topology; it is informed of it. A device three hubs deep is
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// addressed by a route string naming the port taken at each tier, and a
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// slow device behind a fast hub is scheduled against that hub's transaction
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// translator rather than against the device. So this driver's real job is
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// less "operate the hub" than "tell the controller what shape the tree is".
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#include "types.h"
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#include "defs.h"
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#include "param.h"
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#include "spinlock.h"
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#include "dma.h"
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#include "usb.h"
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#define MAX_PORTS 15 // per hub; more than any real bus hub has
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static int
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hub_request(struct usb_dev *dev, int type, int req, int value, int index,
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void *buf, int len)
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{
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struct usb_setup s;
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s.bmRequestType = type;
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s.bRequest = req;
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s.wValue = value;
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s.wIndex = index;
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s.wLength = len;
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return dev->ops->control(dev, &s, buf, len);
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}
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static int
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port_set_feature(struct usb_dev *dev, int port, int feature)
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{
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return hub_request(dev, USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_OTHER,
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USB_REQ_SET_FEATURE, feature, port, 0, 0);
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}
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static int
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port_clear_feature(struct usb_dev *dev, int port, int feature)
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{
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return hub_request(dev, USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_OTHER,
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USB_REQ_CLEAR_FEATURE, feature, port, 0, 0);
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}
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// Returns wPortStatus, or -1. The change bits are in the upper half and are
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// deliberately dropped here -- they are acknowledged separately.
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static int
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port_status(struct usb_dev *dev, int port, void *scratch)
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{
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uint16 *st = scratch;
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if(hub_request(dev, USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_OTHER,
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USB_REQ_GET_STATUS, 0, port, scratch, 4) < 0)
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return -1;
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return st[0];
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}
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// Bring up whatever is plugged into one downstream port.
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static void
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hub_port(struct usb_dev *hub, int port, void *scratch)
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{
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int st, speed, i;
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st = port_status(hub, port, scratch);
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if(st < 0 || !(st & PORTSTAT_CONNECTION))
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return;
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// Acknowledge the connect-change bit before resetting. Leaving it set is
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// harmless here but confuses any later attempt to use these bits for
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// hotplug, which is what they are actually for.
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port_clear_feature(hub, port, PORT_FEAT_C_CONNECTION);
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if(port_set_feature(hub, port, PORT_FEAT_RESET) < 0){
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cprintf("usb-hub: port %d would not reset\n", port);
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return;
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}
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// A hub does not report reset completion by clearing the request; it sets
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// C_PORT_RESET and enables the port. Poll for the enable rather than
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// guessing at a delay, because the time depends on the device.
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for(i = 0; i < 200; i++){
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microdelay(1000);
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st = port_status(hub, port, scratch);
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if(st >= 0 && !(st & PORTSTAT_RESET) && (st & PORTSTAT_ENABLE))
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break;
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}
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port_clear_feature(hub, port, PORT_FEAT_C_RESET);
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st = port_status(hub, port, scratch);
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if(st < 0 || !(st & PORTSTAT_ENABLE)){
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cprintf("usb-hub: port %d did not enable after reset\n", port);
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return;
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}
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// Speed comes out of two status bits rather than a field, and the absence
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// of both means full speed.
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if(st & PORTSTAT_LOWSPEED)
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speed = USB_SPEED_LOW;
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else if(st & PORTSTAT_HIGHSPEED)
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speed = USB_SPEED_HIGH;
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else
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speed = USB_SPEED_FULL;
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// A device needs time to settle after reset before it will answer on
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// endpoint 0. The specification calls this TRSTRCY and allows 10 ms.
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microdelay(20000);
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hub->ops->attach(hub, port, speed);
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}
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static int
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hub_probe(struct usb_dev *dev)
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{
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struct usb_hub_desc *hd;
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void *scratch;
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int nports, mtt, i;
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scratch = dma_alloc(64, 64);
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if(scratch == 0)
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return -1;
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// The hub descriptor is class-specific, so it comes from a class GET
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// request rather than the standard one -- same request number, different
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// recipient and type.
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if(hub_request(dev, USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_DEVICE,
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USB_REQ_GET_DESCRIPTOR, USB_DT_HUB << 8, 0,
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scratch, sizeof(struct usb_hub_desc)) < 0){
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cprintf("usb-hub: no hub descriptor\n");
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dma_free(scratch, 64);
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return -1;
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}
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hd = scratch;
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nports = hd->bNbrPorts;
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if(nports < 1 || nports > MAX_PORTS){
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cprintf("usb-hub: %d ports is not a number of ports\n", nports);
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dma_free(scratch, 64);
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return -1;
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}
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mtt = (hd->wHubCharacteristics & HUB_CHAR_TT_MASK) != 0;
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cprintf("usb-hub: %d ports on slot %d\n", nports, dev->slot);
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// Tell the controller *before* powering anything on. Addressing a device
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// behind a slot the controller does not know is a hub fails, and it fails
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// at Address Device with a completion code rather than anywhere useful.
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if(dev->ops->set_hub(dev, nports, mtt) < 0){
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dma_free(scratch, 64);
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return -1;
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}
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// Ports come up unpowered. bPwrOn2PwrGood is how long the hub says it needs
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// after switching power on before a device behind it is worth talking to,
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// in 2 ms units -- a number the hub knows and we do not.
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for(i = 1; i <= nports; i++)
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port_set_feature(dev, i, PORT_FEAT_POWER);
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microdelay((hd->bPwrOn2PwrGood * 2 + 10) * 1000);
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for(i = 1; i <= nports; i++)
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hub_port(dev, i, scratch);
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dma_free(scratch, 64);
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return 0;
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}
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// Any hub, whatever its protocol: 0 is a full-speed hub, 1 single-TT, 2
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// multi-TT, and they differ only in how transactions are translated, which
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// is the controller's problem rather than ours.
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const struct usb_driver usb_hub_driver = {
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.name = "usb-hub",
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.class = USB_CLASS_HUB,
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.subclass = 0xFF,
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.protocol = 0xFF,
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.devclass = DEVCLASS_BUS,
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.probe = hub_probe,
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};
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