usb: data structs and helpers for usb descriptors.

This patch adds hw/usb-desc.[ch] files.  They carry data structures
for various usb descriptors and helper functions to generate usb
packets from the structures.

The intention is to have a internal representation of the device
desription which is more usable than the current char array blobs,
so we can have common code handle common usb device emulation using
the device description.

The usage of this infrastructure is optional for usb drivers as there
are cases such as pass-through where it probably isn't very useful.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

1 files changed, 238 insertions, 0 deletions

diff --git a/hw/usb-desc.c b/hw/usb-desc.c
new file mode 100644
index 000000000..559ced78b
--- /dev/null
+++ b/hw/usb-desc.c
@@ -0,0 +1,238 @@
+#include "usb.h"
+#include "usb-desc.h"
+#include "trace.h"
+
+/* ------------------------------------------------------------------ */
+
+static uint8_t usb_lo(uint16_t val)
+{
+    return val & 0xff;
+}
+
+static uint8_t usb_hi(uint16_t val)
+{
+    return (val >> 8) & 0xff;
+}
+
+int usb_desc_device(const USBDescID *id, const USBDescDevice *dev,
+                    uint8_t *dest, size_t len)
+{
+    uint8_t bLength = 0x12;
+
+    if (len < bLength) {
+        return -1;
+    }
+
+    dest[0x00] = bLength;
+    dest[0x01] = USB_DT_DEVICE;
+
+    dest[0x02] = usb_lo(dev->bcdUSB);
+    dest[0x03] = usb_hi(dev->bcdUSB);
+    dest[0x04] = dev->bDeviceClass;
+    dest[0x05] = dev->bDeviceSubClass;
+    dest[0x06] = dev->bDeviceProtocol;
+    dest[0x07] = dev->bMaxPacketSize0;
+
+    dest[0x08] = usb_lo(id->idVendor);
+    dest[0x09] = usb_hi(id->idVendor);
+    dest[0x0a] = usb_lo(id->idProduct);
+    dest[0x0b] = usb_hi(id->idProduct);
+    dest[0x0c] = usb_lo(id->bcdDevice);
+    dest[0x0d] = usb_hi(id->bcdDevice);
+    dest[0x0e] = id->iManufacturer;
+    dest[0x0f] = id->iProduct;
+    dest[0x10] = id->iSerialNumber;
+
+    dest[0x11] = dev->bNumConfigurations;
+
+    return bLength;
+}
+
+int usb_desc_config(const USBDescConfig *conf, uint8_t *dest, size_t len)
+{
+    uint8_t  bLength = 0x09;
+    uint16_t wTotalLength = 0;
+    int i, rc, count;
+
+    if (len < bLength) {
+        return -1;
+    }
+
+    dest[0x00] = bLength;
+    dest[0x01] = USB_DT_CONFIG;
+    dest[0x04] = conf->bNumInterfaces;
+    dest[0x05] = conf->bConfigurationValue;
+    dest[0x06] = conf->iConfiguration;
+    dest[0x07] = conf->bmAttributes;
+    dest[0x08] = conf->bMaxPower;
+    wTotalLength += bLength;
+
+    count = conf->nif ? conf->nif : conf->bNumInterfaces;
+    for (i = 0; i < count; i++) {
+        rc = usb_desc_iface(conf->ifs + i, dest + wTotalLength, len - wTotalLength);
+        if (rc < 0) {
+            return rc;
+        }
+        wTotalLength += rc;
+    }
+
+    dest[0x02] = usb_lo(wTotalLength);
+    dest[0x03] = usb_hi(wTotalLength);
+    return wTotalLength;
+}
+
+int usb_desc_iface(const USBDescIface *iface, uint8_t *dest, size_t len)
+{
+    uint8_t bLength = 0x09;
+    int i, rc, pos = 0;
+
+    if (len < bLength) {
+        return -1;
+    }
+
+    dest[0x00] = bLength;
+    dest[0x01] = USB_DT_INTERFACE;
+    dest[0x02] = iface->bInterfaceNumber;
+    dest[0x03] = iface->bAlternateSetting;
+    dest[0x04] = iface->bNumEndpoints;
+    dest[0x05] = iface->bInterfaceClass;
+    dest[0x06] = iface->bInterfaceSubClass;
+    dest[0x07] = iface->bInterfaceProtocol;
+    dest[0x08] = iface->iInterface;
+    pos += bLength;
+
+    for (i = 0; i < iface->ndesc; i++) {
+        rc = usb_desc_other(iface->descs + i, dest + pos, len - pos);
+        if (rc < 0) {
+            return rc;
+        }
+        pos += rc;
+    }
+
+    for (i = 0; i < iface->bNumEndpoints; i++) {
+        rc = usb_desc_endpoint(iface->eps + i, dest + pos, len - pos);
+        if (rc < 0) {
+            return rc;
+        }
+        pos += rc;
+    }
+
+    return pos;
+}
+
+int usb_desc_endpoint(const USBDescEndpoint *ep, uint8_t *dest, size_t len)
+{
+    uint8_t bLength = 0x07;
+
+    if (len < bLength) {
+        return -1;
+    }
+
+    dest[0x00] = bLength;
+    dest[0x01] = USB_DT_ENDPOINT;
+    dest[0x02] = ep->bEndpointAddress;
+    dest[0x03] = ep->bmAttributes;
+    dest[0x04] = usb_lo(ep->wMaxPacketSize);
+    dest[0x05] = usb_hi(ep->wMaxPacketSize);
+    dest[0x06] = ep->bInterval;
+
+    return bLength;
+}
+
+int usb_desc_other(const USBDescOther *desc, uint8_t *dest, size_t len)
+{
+    int bLength = desc->length ? desc->length : desc->data[0];
+
+    if (len < bLength) {
+        return -1;
+    }
+
+    memcpy(dest, desc->data, bLength);
+    return bLength;
+}
+
+int usb_desc_string(const char* const *str, int index, uint8_t *dest, size_t len)
+{
+    uint8_t bLength, pos, i;
+
+    if (len < 4) {
+        return -1;
+    }
+
+    if (index == 0) {
+        /* language ids */
+        dest[0] = 4;
+        dest[1] = USB_DT_STRING;
+        dest[2] = 0x09;
+        dest[3] = 0x04;
+        return 4;
+    }
+
+    if (str[index] == NULL) {
+        return 0;
+    }
+    bLength = strlen(str[index]) * 2 + 2;
+    dest[0] = bLength;
+    dest[1] = USB_DT_STRING;
+    i = 0; pos = 2;
+    while (pos+1 < bLength && pos+1 < len) {
+        dest[pos++] = str[index][i++];
+        dest[pos++] = 0;
+    }
+    return pos;
+}
+
+/* ------------------------------------------------------------------ */
+
+int usb_desc_get_descriptor(USBDevice *dev, int value, uint8_t *dest, size_t len)
+{
+    const USBDesc *desc = dev->info->usb_desc;
+    uint8_t buf[256];
+    uint8_t type = value >> 8;
+    uint8_t index = value & 0xff;
+    int ret = -1;
+
+    switch(type) {
+    case USB_DT_DEVICE:
+        ret = usb_desc_device(&desc->id, desc->full, buf, sizeof(buf));
+        trace_usb_desc_device(dev->addr, len, ret);
+        break;
+    case USB_DT_CONFIG:
+        if (index < desc->full->bNumConfigurations) {
+            ret = usb_desc_config(desc->full->confs + index, buf, sizeof(buf));
+        }
+        trace_usb_desc_config(dev->addr, index, len, ret);
+        break;
+    case USB_DT_STRING:
+        ret = usb_desc_string(desc->str, index, buf, sizeof(buf));
+        trace_usb_desc_string(dev->addr, index, len, ret);
+        break;
+    default:
+        fprintf(stderr, "%s: %d unknown type %d (len %zd)\n", __FUNCTION__,
+                dev->addr, type, len);
+        break;
+    }
+
+    if (ret > 0) {
+        if (ret > len) {
+            ret = len;
+        }
+        memcpy(dest, buf, ret);
+    }
+    return ret;
+}
+
+int usb_desc_handle_control(USBDevice *dev, int request, int value,
+                            int index, int length, uint8_t *data)
+{
+    const USBDesc *desc = dev->info->usb_desc;
+    int ret = -1;
+
+    assert(desc != NULL);
+    switch(request) {
+    case DeviceRequest | USB_REQ_GET_DESCRIPTOR:
+        ret = usb_desc_get_descriptor(dev, value, data, length);
+        break;
+    }
+    return ret;
+}