/*
* uss720.c -- USS720 USB Parport Cable.
*
- * Copyright (C) 1999
- * Thomas Sailer (sailer@ife.ee.ethz.ch)
+ * Copyright (C) 1999, 2005
+ * Thomas Sailer (t.sailer@alumni.ethz.ch)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* Based on parport_pc.c
*
* History:
- * 0.1 04.08.99 Created
- * 0.2 07.08.99 Some fixes mainly suggested by Tim Waugh
- * Interrupt handling currently disabled because
- * usb_request_irq crashes somewhere within ohci.c
- * for no apparent reason (that is for me, anyway)
- * ECP currently untested
- * 0.3 10.08.99 fixing merge errors
- * 0.4 13.08.99 Added Vendor/Product ID of Brad Hard's cable
- * 0.5 20.09.99 usb_control_msg wrapper used
- * Nov01.00 usb_device_table support by Adam J. Richter
- * 08.04.01 Identify version on module load. gb
+ * 0.1 04.08.1999 Created
+ * 0.2 07.08.1999 Some fixes mainly suggested by Tim Waugh
+ * Interrupt handling currently disabled because
+ * usb_request_irq crashes somewhere within ohci.c
+ * for no apparent reason (that is for me, anyway)
+ * ECP currently untested
+ * 0.3 10.08.1999 fixing merge errors
+ * 0.4 13.08.1999 Added Vendor/Product ID of Brad Hard's cable
+ * 0.5 20.09.1999 usb_control_msg wrapper used
+ * Nov01.2000 usb_device_table support by Adam J. Richter
+ * 08.04.2001 Identify version on module load. gb
+ * 0.6 02.09.2005 Fix "scheduling in interrupt" problem by making save/restore
+ * context asynchronous
*
*/
#include <linux/init.h>
#include <linux/usb.h>
#include <linux/delay.h>
+#include <linux/completion.h>
+#include <linux/kref.h>
/*
* Version Information
*/
-#define DRIVER_VERSION "v0.5"
-#define DRIVER_AUTHOR "Thomas M. Sailer, sailer@ife.ee.ethz.ch"
+#define DRIVER_VERSION "v0.6"
+#define DRIVER_AUTHOR "Thomas M. Sailer, t.sailer@alumni.ethz.ch"
#define DRIVER_DESC "USB Parport Cable driver for Cables using the Lucent Technologies USS720 Chip"
/* --------------------------------------------------------------------- */
struct parport_uss720_private {
struct usb_device *usbdev;
- void *irqhandle;
- unsigned int irqpipe;
- unsigned char reg[7]; /* USB registers */
+ struct parport *pp;
+ struct kref ref_count;
+ __u8 reg[7]; /* USB registers */
+ struct list_head asynclist;
+ spinlock_t asynclock;
+};
+
+struct uss720_async_request {
+ struct parport_uss720_private *priv;
+ struct kref ref_count;
+ struct list_head asynclist;
+ struct completion compl;
+ struct urb *urb;
+ struct usb_ctrlrequest dr;
+ __u8 reg[7];
};
/* --------------------------------------------------------------------- */
-static int get_1284_register(struct parport *pp, unsigned char reg, unsigned char *val)
+static void destroy_priv(struct kref *kref)
{
- struct parport_uss720_private *priv = pp->private_data;
- struct usb_device *usbdev = priv->usbdev;
- static const unsigned char regindex[9] = {
- 4, 0, 1, 5, 5, 0, 2, 3, 6
- };
- int ret;
+ struct parport_uss720_private *priv = container_of(kref, struct parport_uss720_private, ref_count);
- if (!usbdev)
- return -1;
- ret = usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev,0), 3, 0xc0, ((unsigned int)reg) << 8, 0, priv->reg, 7, 1000);
- if (ret != 7) {
- printk(KERN_DEBUG "uss720: get_1284_register(%d) failed, status 0x%x expected 7\n",
- (unsigned int)reg, ret);
- ret = -1;
- } else {
+ usb_put_dev(priv->usbdev);
+ kfree(priv);
+ dbg("destroying priv datastructure");
+}
+
+static void destroy_async(struct kref *kref)
+{
+ struct uss720_async_request *rq = container_of(kref, struct uss720_async_request, ref_count);
+ struct parport_uss720_private *priv = rq->priv;
+ unsigned long flags;
+
+ if (likely(rq->urb))
+ usb_free_urb(rq->urb);
+ spin_lock_irqsave(&priv->asynclock, flags);
+ list_del_init(&rq->asynclist);
+ spin_unlock_irqrestore(&priv->asynclock, flags);
+ kfree(rq);
+ kref_put(&priv->ref_count, destroy_priv);
+}
+
+/* --------------------------------------------------------------------- */
+
+static void async_complete(struct urb *urb, struct pt_regs *ptregs)
+{
+ struct uss720_async_request *rq;
+ struct parport *pp;
+ struct parport_uss720_private *priv;
+
+ rq = urb->context;
+ priv = rq->priv;
+ pp = priv->pp;
+ if (urb->status) {
+ err("async_complete: urb error %d", urb->status);
+ } else if (rq->dr.bRequest == 3) {
+ memcpy(priv->reg, rq->reg, sizeof(priv->reg));
#if 0
- printk(KERN_DEBUG "uss720: get_1284_register(%d) return %02x %02x %02x %02x %02x %02x %02x\n",
- (unsigned int)reg, (unsigned int)priv->reg[0], (unsigned int)priv->reg[1],
- (unsigned int)priv->reg[2], (unsigned int)priv->reg[3], (unsigned int)priv->reg[4],
- (unsigned int)priv->reg[5], (unsigned int)priv->reg[6]);
+ dbg("async_complete regs %02x %02x %02x %02x %02x %02x %02x",
+ (unsigned int)priv->reg[0], (unsigned int)priv->reg[1], (unsigned int)priv->reg[2],
+ (unsigned int)priv->reg[3], (unsigned int)priv->reg[4], (unsigned int)priv->reg[5],
+ (unsigned int)priv->reg[6]);
#endif
/* if nAck interrupts are enabled and we have an interrupt, call the interrupt procedure */
- if (priv->reg[2] & priv->reg[1] & 0x10)
+ if (rq->reg[2] & rq->reg[1] & 0x10 && pp)
parport_generic_irq(0, pp, NULL);
- ret = 0;
}
- if (val)
- *val = priv->reg[(reg >= 9) ? 0 : regindex[reg]];
- return ret;
+ complete(&rq->compl);
+ kref_put(&rq->ref_count, destroy_async);
}
-static int set_1284_register(struct parport *pp, unsigned char reg, unsigned char val)
+static struct uss720_async_request *submit_async_request(struct parport_uss720_private *priv,
+ __u8 request, __u8 requesttype, __u16 value, __u16 index,
+ gfp_t mem_flags)
{
- struct parport_uss720_private *priv = pp->private_data;
- struct usb_device *usbdev = priv->usbdev;
+ struct usb_device *usbdev;
+ struct uss720_async_request *rq;
+ unsigned long flags;
int ret;
+ if (!priv)
+ return NULL;
+ usbdev = priv->usbdev;
if (!usbdev)
- return -1;
- ret = usb_control_msg(usbdev, usb_sndctrlpipe(usbdev,0), 4, 0x40, (((unsigned int)reg) << 8) | val, 0, NULL, 0, 1000);
- if (ret) {
- printk(KERN_DEBUG "uss720: set_1284_register(%u,0x%02x) failed, status 0x%x\n",
- (unsigned int)reg, (unsigned int)val, ret);
- } else {
-#if 0
- printk(KERN_DEBUG "uss720: set_1284_register(%u,0x%02x)\n",
- (unsigned int)reg, (unsigned int)val);
-#endif
+ return NULL;
+ rq = kmalloc(sizeof(struct uss720_async_request), mem_flags);
+ if (!rq) {
+ err("submit_async_request out of memory");
+ return NULL;
+ }
+ kref_init(&rq->ref_count);
+ INIT_LIST_HEAD(&rq->asynclist);
+ init_completion(&rq->compl);
+ kref_get(&priv->ref_count);
+ rq->priv = priv;
+ rq->urb = usb_alloc_urb(0, mem_flags);
+ if (!rq->urb) {
+ kref_put(&rq->ref_count, destroy_async);
+ err("submit_async_request out of memory");
+ return NULL;
}
+ rq->dr.bRequestType = requesttype;
+ rq->dr.bRequest = request;
+ rq->dr.wValue = cpu_to_le16(value);
+ rq->dr.wIndex = cpu_to_le16(index);
+ rq->dr.wLength = cpu_to_le16((request == 3) ? sizeof(rq->reg) : 0);
+ usb_fill_control_urb(rq->urb, usbdev, (requesttype & 0x80) ? usb_rcvctrlpipe(usbdev, 0) : usb_sndctrlpipe(usbdev, 0),
+ (unsigned char *)&rq->dr,
+ (request == 3) ? rq->reg : NULL, (request == 3) ? sizeof(rq->reg) : 0, async_complete, rq);
+ /* rq->urb->transfer_flags |= URB_ASYNC_UNLINK; */
+ spin_lock_irqsave(&priv->asynclock, flags);
+ list_add_tail(&rq->asynclist, &priv->asynclist);
+ spin_unlock_irqrestore(&priv->asynclock, flags);
+ ret = usb_submit_urb(rq->urb, mem_flags);
+ if (!ret) {
+ kref_get(&rq->ref_count);
+ return rq;
+ }
+ kref_put(&rq->ref_count, destroy_async);
+ err("submit_async_request submit_urb failed with %d", ret);
+ return NULL;
+}
+
+static unsigned int kill_all_async_requests_priv(struct parport_uss720_private *priv)
+{
+ struct uss720_async_request *rq;
+ unsigned long flags;
+ unsigned int ret = 0;
+
+ spin_lock_irqsave(&priv->asynclock, flags);
+ list_for_each_entry(rq, &priv->asynclist, asynclist) {
+ usb_unlink_urb(rq->urb);
+ ret++;
+ }
+ spin_unlock_irqrestore(&priv->asynclock, flags);
return ret;
}
/* --------------------------------------------------------------------- */
+static int get_1284_register(struct parport *pp, unsigned char reg, unsigned char *val, gfp_t mem_flags)
+{
+ struct parport_uss720_private *priv;
+ struct uss720_async_request *rq;
+ static const unsigned char regindex[9] = {
+ 4, 0, 1, 5, 5, 0, 2, 3, 6
+ };
+ int ret;
+
+ if (!pp)
+ return -EIO;
+ priv = pp->private_data;
+ rq = submit_async_request(priv, 3, 0xc0, ((unsigned int)reg) << 8, 0, mem_flags);
+ if (!rq) {
+ err("get_1284_register(%u) failed", (unsigned int)reg);
+ return -EIO;
+ }
+ if (!val) {
+ kref_put(&rq->ref_count, destroy_async);
+ return 0;
+ }
+ if (wait_for_completion_timeout(&rq->compl, HZ)) {
+ ret = rq->urb->status;
+ *val = priv->reg[(reg >= 9) ? 0 : regindex[reg]];
+ if (ret)
+ warn("get_1284_register: usb error %d", ret);
+ kref_put(&rq->ref_count, destroy_async);
+ return ret;
+ }
+ warn("get_1284_register timeout");
+ kill_all_async_requests_priv(priv);
+ return -EIO;
+}
+
+static int set_1284_register(struct parport *pp, unsigned char reg, unsigned char val, gfp_t mem_flags)
+{
+ struct parport_uss720_private *priv;
+ struct uss720_async_request *rq;
+
+ if (!pp)
+ return -EIO;
+ priv = pp->private_data;
+ rq = submit_async_request(priv, 4, 0x40, (((unsigned int)reg) << 8) | val, 0, mem_flags);
+ if (!rq) {
+ err("set_1284_register(%u,%u) failed", (unsigned int)reg, (unsigned int)val);
+ return -EIO;
+ }
+ kref_put(&rq->ref_count, destroy_async);
+ return 0;
+}
+
+/* --------------------------------------------------------------------- */
+
/* ECR modes */
#define ECR_SPP 00
#define ECR_PS2 01
{
struct parport_uss720_private *priv = pp->private_data;
int mode;
+ __u8 reg;
- if (get_1284_register(pp, 6, NULL))
+ if (get_1284_register(pp, 6, ®, GFP_KERNEL))
return -EIO;
/* Bits <7:5> contain the mode. */
mode = (priv->reg[2] >> 5) & 0x7;
case ECR_ECP: /* ECP Parallel Port mode */
/* Poll slowly. */
for (;;) {
- if (get_1284_register(pp, 6, NULL))
+ if (get_1284_register(pp, 6, ®, GFP_KERNEL))
return -EIO;
if (priv->reg[2] & 0x01)
break;
}
}
/* Set the mode. */
- if (set_1284_register(pp, 6, m << 5))
+ if (set_1284_register(pp, 6, m << 5, GFP_KERNEL))
+ return -EIO;
+ if (get_1284_register(pp, 6, ®, GFP_KERNEL))
return -EIO;
return 0;
}
{
unsigned char stat;
- if (get_1284_register(pp, 1, &stat))
+ if (get_1284_register(pp, 1, &stat, GFP_KERNEL))
return 1;
return stat & 1;
}
static void parport_uss720_write_data(struct parport *pp, unsigned char d)
{
- set_1284_register(pp, 0, d);
+ set_1284_register(pp, 0, d, GFP_KERNEL);
}
static unsigned char parport_uss720_read_data(struct parport *pp)
{
unsigned char ret;
- if (get_1284_register(pp, 0, &ret))
+ if (get_1284_register(pp, 0, &ret, GFP_KERNEL))
return 0;
return ret;
}
struct parport_uss720_private *priv = pp->private_data;
d = (d & 0xf) | (priv->reg[1] & 0xf0);
- if (set_1284_register(pp, 2, d))
+ if (set_1284_register(pp, 2, d, GFP_KERNEL))
return;
priv->reg[1] = d;
}
mask &= 0x0f;
val &= 0x0f;
d = (priv->reg[1] & (~mask)) ^ val;
- if (set_1284_register(pp, 2, d))
+ if (set_1284_register(pp, 2, d, GFP_KERNEL))
return 0;
priv->reg[1] = d;
return d & 0xf;
{
unsigned char ret;
- if (get_1284_register(pp, 1, &ret))
+ if (get_1284_register(pp, 1, &ret, GFP_KERNEL))
return 0;
return ret & 0xf8;
}
unsigned char d;
d = priv->reg[1] & ~0x10;
- if (set_1284_register(pp, 2, d))
+ if (set_1284_register(pp, 2, d, GFP_KERNEL))
return;
priv->reg[1] = d;
}
unsigned char d;
d = priv->reg[1] | 0x10;
- if (set_1284_register(pp, 2, d))
+ if (set_1284_register(pp, 2, d, GFP_KERNEL))
return;
priv->reg[1] = d;
}
unsigned char d;
d = priv->reg[1] & ~0x20;
- if (set_1284_register(pp, 2, d))
+ if (set_1284_register(pp, 2, d, GFP_KERNEL))
return;
priv->reg[1] = d;
}
unsigned char d;
d = priv->reg[1] | 0x20;
- if (set_1284_register(pp, 2, d))
+ if (set_1284_register(pp, 2, d, GFP_KERNEL))
return;
priv->reg[1] = d;
}
{
struct parport_uss720_private *priv = pp->private_data;
- if (get_1284_register(pp, 2, NULL))
+#if 0
+ if (get_1284_register(pp, 2, NULL, GFP_ATOMIC))
return;
+#endif
s->u.pc.ctr = priv->reg[1];
s->u.pc.ecr = priv->reg[2];
}
static void parport_uss720_restore_state(struct parport *pp, struct parport_state *s)
{
- set_1284_register(pp, 2, s->u.pc.ctr);
- set_1284_register(pp, 6, s->u.pc.ecr);
- get_1284_register(pp, 2, NULL);
+ struct parport_uss720_private *priv = pp->private_data;
+
+ set_1284_register(pp, 2, s->u.pc.ctr, GFP_ATOMIC);
+ set_1284_register(pp, 6, s->u.pc.ecr, GFP_ATOMIC);
+ get_1284_register(pp, 2, NULL, GFP_ATOMIC);
+ priv->reg[1] = s->u.pc.ctr;
+ priv->reg[2] = s->u.pc.ecr;
}
static size_t parport_uss720_epp_read_data(struct parport *pp, void *buf, size_t length, int flags)
if (change_mode(pp, ECR_EPP))
return 0;
for (; got < length; got++) {
- if (get_1284_register(pp, 4, (char *)buf))
+ if (get_1284_register(pp, 4, (char *)buf, GFP_KERNEL))
break;
buf++;
if (priv->reg[0] & 0x01) {
if (change_mode(pp, ECR_EPP))
return 0;
for (; written < length; written++) {
- if (set_1284_register(pp, 4, (char *)buf))
+ if (set_1284_register(pp, 4, (char *)buf, GFP_KERNEL))
break;
((char*)buf)++;
- if (get_1284_register(pp, 1, NULL))
+ if (get_1284_register(pp, 1, NULL, GFP_KERNEL))
break;
if (priv->reg[0] & 0x01) {
clear_epp_timeout(pp);
if (change_mode(pp, ECR_EPP))
return 0;
for (; got < length; got++) {
- if (get_1284_register(pp, 3, (char *)buf))
+ if (get_1284_register(pp, 3, (char *)buf, GFP_KERNEL))
break;
buf++;
if (priv->reg[0] & 0x01) {
if (change_mode(pp, ECR_EPP))
return 0;
for (; written < length; written++) {
- if (set_1284_register(pp, 3, *(char *)buf))
+ if (set_1284_register(pp, 3, *(char *)buf, GFP_KERNEL))
break;
buf++;
- if (get_1284_register(pp, 1, NULL))
+ if (get_1284_register(pp, 1, NULL, GFP_KERNEL))
break;
if (priv->reg[0] & 0x01) {
clear_epp_timeout(pp);
if (change_mode(pp, ECR_ECP))
return 0;
for (; written < len; written++) {
- if (set_1284_register(pp, 5, *(char *)buffer))
+ if (set_1284_register(pp, 5, *(char *)buffer, GFP_KERNEL))
break;
buffer++;
}
static int uss720_probe(struct usb_interface *intf,
const struct usb_device_id *id)
{
- struct usb_device *usbdev = interface_to_usbdev(intf);
+ struct usb_device *usbdev = usb_get_dev(interface_to_usbdev(intf));
struct usb_host_interface *interface;
struct usb_host_endpoint *endpoint;
struct parport_uss720_private *priv;
struct parport *pp;
+ unsigned char reg;
int i;
- printk(KERN_DEBUG "uss720: probe: vendor id 0x%x, device id 0x%x\n",
- le16_to_cpu(usbdev->descriptor.idVendor),
- le16_to_cpu(usbdev->descriptor.idProduct));
+ dbg("probe: vendor id 0x%x, device id 0x%x\n",
+ le16_to_cpu(usbdev->descriptor.idVendor),
+ le16_to_cpu(usbdev->descriptor.idProduct));
/* our known interfaces have 3 alternate settings */
- if (intf->num_altsetting != 3)
+ if (intf->num_altsetting != 3) {
+ usb_put_dev(usbdev);
return -ENODEV;
-
+ }
i = usb_set_interface(usbdev, intf->altsetting->desc.bInterfaceNumber, 2);
- printk(KERN_DEBUG "uss720: set inteface result %d\n", i);
+ dbg("set inteface result %d", i);
interface = intf->cur_altsetting;
/*
* Allocate parport interface
*/
- printk(KERN_INFO "uss720: (C) 1999 by Thomas Sailer, <sailer@ife.ee.ethz.ch>\n");
-
- if (!(priv = kmalloc(sizeof(struct parport_uss720_private), GFP_KERNEL)))
+ if (!(priv = kcalloc(sizeof(struct parport_uss720_private), 1, GFP_KERNEL))) {
+ usb_put_dev(usbdev);
return -ENOMEM;
+ }
+ priv->pp = NULL;
+ priv->usbdev = usbdev;
+ kref_init(&priv->ref_count);
+ spin_lock_init(&priv->asynclock);
+ INIT_LIST_HEAD(&priv->asynclist);
if (!(pp = parport_register_port(0, PARPORT_IRQ_NONE, PARPORT_DMA_NONE, &parport_uss720_ops))) {
- printk(KERN_WARNING "usb-uss720: could not register parport\n");
+ warn("could not register parport");
goto probe_abort;
}
+ priv->pp = pp;
pp->private_data = priv;
- priv->usbdev = usbdev;
pp->modes = PARPORT_MODE_PCSPP | PARPORT_MODE_TRISTATE | PARPORT_MODE_EPP | PARPORT_MODE_ECP | PARPORT_MODE_COMPAT;
/* set the USS720 control register to manual mode, no ECP compression, enable all ints */
- set_1284_register(pp, 7, 0x00);
- set_1284_register(pp, 6, 0x30); /* PS/2 mode */
- set_1284_register(pp, 2, 0x0c);
+ set_1284_register(pp, 7, 0x00, GFP_KERNEL);
+ set_1284_register(pp, 6, 0x30, GFP_KERNEL); /* PS/2 mode */
+ set_1284_register(pp, 2, 0x0c, GFP_KERNEL);
/* debugging */
- get_1284_register(pp, 0, NULL);
- printk("uss720: reg: %02x %02x %02x %02x %02x %02x %02x\n",
- priv->reg[0], priv->reg[1], priv->reg[2], priv->reg[3], priv->reg[4], priv->reg[5], priv->reg[6]);
+ get_1284_register(pp, 0, ®, GFP_KERNEL);
+ dbg("reg: %02x %02x %02x %02x %02x %02x %02x",
+ priv->reg[0], priv->reg[1], priv->reg[2], priv->reg[3], priv->reg[4], priv->reg[5], priv->reg[6]);
endpoint = &interface->endpoint[2];
- printk(KERN_DEBUG "uss720: epaddr %d interval %d\n", endpoint->desc.bEndpointAddress, endpoint->desc.bInterval);
-#if 0
- priv->irqpipe = usb_rcvctrlpipe(usbdev, endpoint->bEndpointAddress);
- i = usb_request_irq(usbdev, priv->irqpipe,
- uss720_irq, endpoint->bInterval,
- pp, &priv->irqhandle);
- if (i) {
- printk (KERN_WARNING "usb-uss720: usb_request_irq failed (0x%x)\n", i);
- goto probe_abort_port;
- }
-#endif
+ dbg("epaddr %d interval %d", endpoint->desc.bEndpointAddress, endpoint->desc.bInterval);
parport_announce_port(pp);
- usb_set_intfdata (intf, pp);
+ usb_set_intfdata(intf, pp);
return 0;
-#if 0
-probe_abort_port:
- parport_put_port(pp);
-#endif
probe_abort:
- kfree(priv);
+ kill_all_async_requests_priv(priv);
+ kref_put(&priv->ref_count, destroy_priv);
return -ENODEV;
}
static void uss720_disconnect(struct usb_interface *intf)
{
- struct parport *pp = usb_get_intfdata (intf);
+ struct parport *pp = usb_get_intfdata(intf);
struct parport_uss720_private *priv;
+ struct usb_device *usbdev;
- usb_set_intfdata (intf, NULL);
+ dbg("disconnect");
+ usb_set_intfdata(intf, NULL);
if (pp) {
priv = pp->private_data;
- parport_remove_port(pp);
-#if 0
- usb_release_irq(usbdev, priv->irqhandle, priv->irqpipe);
-#endif
+ usbdev = priv->usbdev;
priv->usbdev = NULL;
+ priv->pp = NULL;
+ dbg("parport_remove_port");
+ parport_remove_port(pp);
parport_put_port(pp);
- kfree(priv);
+ kill_all_async_requests_priv(priv);
+ kref_put(&priv->ref_count, destroy_priv);
}
+ dbg("disconnect done");
}
/* table of cables that work through this driver */
static struct usb_driver uss720_driver = {
- .owner = THIS_MODULE,
.name = "uss720",
.probe = uss720_probe,
.disconnect = uss720_disconnect,
/* --------------------------------------------------------------------- */
-MODULE_AUTHOR( DRIVER_AUTHOR );
-MODULE_DESCRIPTION( DRIVER_DESC );
+MODULE_AUTHOR(DRIVER_AUTHOR);
+MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");
static int __init uss720_init(void)
goto out;
info(DRIVER_VERSION ":" DRIVER_DESC);
+ info("NOTE: this is a special purpose driver to allow nonstandard");
+ info("protocols (eg. bitbang) over USS720 usb to parallel cables");
+ info("If you just want to connect to a printer, use usblp instead");
out:
return retval;
}
git://git.onelab.eu / linux-2.6.git / blobdiff