[PATCH] isdn4linux: Siemens Gigaset drivers - M105 USB DECT adapter

And: Tilman Schmidt <tilman@imap.cc>

This patch adds the connection-specific module "usb_gigaset", the hardware
driver for Gigaset base stations connected via the M105 USB DECT adapter.  It
contains the code for handling probe/disconnect, AT command/response
transmission, and call setup and termination, as well as handling asynchronous
data transfers, PPP framing, byte stuffing, and flow control.

Signed-off-by: Hansjoerg Lipp <hjlipp@web.de>
Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 597 insertions, 0 deletions

diff --git a/drivers/isdn/gigaset/asyncdata.c b/drivers/isdn/gigaset/asyncdata.c
new file mode 100644
index 000000000000..171f8b703d61
--- /dev/null
+++ b/drivers/isdn/gigaset/asyncdata.c
@@ -0,0 +1,597 @@
+/*
+ * Common data handling layer for ser_gigaset and usb_gigaset
+ *
+ * Copyright (c) 2005 by Tilman Schmidt <tilman@imap.cc>,
+ *                       Hansjoerg Lipp <hjlipp@web.de>,
+ *                       Stefan Eilers <Eilers.Stefan@epost.de>.
+ *
+ * =====================================================================
+ *	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 the Free Software Foundation; either version 2 of
+ *	the License, or (at your option) any later version.
+ * =====================================================================
+ * ToDo: ...
+ * =====================================================================
+ * Version: $Id: asyncdata.c,v 1.2.2.7 2005/11/13 23:05:18 hjlipp Exp $
+ * =====================================================================
+ */
+
+#include "gigaset.h"
+#include <linux/crc-ccitt.h>
+
+//#define GIG_M10x_STUFF_VOICE_DATA
+
+/* check if byte must be stuffed/escaped
+ * I'm not sure which data should be encoded.
+ * Therefore I will go the hard way and decode every value
+ * less than 0x20, the flag sequence and the control escape char.
+ */
+static inline int muststuff(unsigned char c)
+{
+	if (c < PPP_TRANS) return 1;
+	if (c == PPP_FLAG) return 1;
+	if (c == PPP_ESCAPE) return 1;
+	/* other possible candidates: */
+	/* 0x91: XON with parity set */
+	/* 0x93: XOFF with parity set */
+	return 0;
+}
+
+/* == data input =========================================================== */
+
+/* process a block of received bytes in command mode (modem response)
+ * Return value:
+ *	number of processed bytes
+ */
+static inline int cmd_loop(unsigned char c, unsigned char *src, int numbytes,
+                           struct inbuf_t *inbuf)
+{
+	struct cardstate *cs = inbuf->cs;
+	unsigned cbytes      = cs->cbytes;
+	int inputstate = inbuf->inputstate;
+	int startbytes = numbytes;
+
+	for (;;) {
+		cs->respdata[cbytes] = c;
+		if (c == 10 || c == 13) {
+			dbg(DEBUG_TRANSCMD, "%s: End of Command (%d Bytes)",
+			    __func__, cbytes);
+			cs->cbytes = cbytes;
+			gigaset_handle_modem_response(cs); /* can change cs->dle */
+			cbytes = 0;
+
+			if (cs->dle &&
+			    !(inputstate & INS_DLE_command)) {
+				inputstate &= ~INS_command;
+				break;
+			}
+		} else {
+			/* advance in line buffer, checking for overflow */
+			if (cbytes < MAX_RESP_SIZE - 1)
+				cbytes++;
+			else
+				warn("response too large");
+		}
+
+		if (!numbytes)
+			break;
+		c = *src++;
+		--numbytes;
+		if (c == DLE_FLAG &&
+		    (cs->dle || inputstate & INS_DLE_command)) {
+			inputstate |= INS_DLE_char;
+			break;
+		}
+	}
+
+	cs->cbytes = cbytes;
+	inbuf->inputstate = inputstate;
+
+	return startbytes - numbytes;
+}
+
+/* process a block of received bytes in lock mode (tty i/f)
+ * Return value:
+ *	number of processed bytes
+ */
+static inline int lock_loop(unsigned char *src, int numbytes,
+                            struct inbuf_t *inbuf)
+{
+	struct cardstate *cs = inbuf->cs;
+
+	gigaset_dbg_buffer(DEBUG_LOCKCMD, "received response", numbytes, src, 0);
+	gigaset_if_receive(cs, src, numbytes);
+
+	return numbytes;
+}
+
+/* process a block of received bytes in HDLC data mode
+ * Collect HDLC frames, undoing byte stuffing and watching for DLE escapes.
+ * When a frame is complete, check the FCS and pass valid frames to the LL.
+ * If DLE is encountered, return immediately to let the caller handle it.
+ * Return value:
+ *	number of processed bytes
+ *	numbytes (all bytes processed) on error --FIXME
+ */
+static inline int hdlc_loop(unsigned char c, unsigned char *src, int numbytes,
+                            struct inbuf_t *inbuf)
+{
+	struct cardstate *cs = inbuf->cs;
+	struct bc_state *bcs = inbuf->bcs;
+	int inputstate;
+	__u16 fcs;
+	struct sk_buff *skb;
+	unsigned char error;
+	struct sk_buff *compskb;
+	int startbytes = numbytes;
+	int l;
+
+	IFNULLRETVAL(bcs, numbytes);
+	inputstate = bcs->inputstate;
+	fcs = bcs->fcs;
+	skb = bcs->skb;
+	IFNULLRETVAL(skb, numbytes);
+
+	if (unlikely(inputstate & INS_byte_stuff)) {
+		inputstate &= ~INS_byte_stuff;
+		goto byte_stuff;
+	}
+	for (;;) {
+		if (unlikely(c == PPP_ESCAPE)) {
+			if (unlikely(!numbytes)) {
+				inputstate |= INS_byte_stuff;
+				break;
+			}
+			c = *src++;
+			--numbytes;
+			if (unlikely(c == DLE_FLAG &&
+				     (cs->dle ||
+				      inbuf->inputstate & INS_DLE_command))) {
+				inbuf->inputstate |= INS_DLE_char;
+				inputstate |= INS_byte_stuff;
+				break;
+			}
+byte_stuff:
+			c ^= PPP_TRANS;
+#ifdef CONFIG_GIGASET_DEBUG
+			if (unlikely(!muststuff(c)))
+				dbg(DEBUG_HDLC,
+				    "byte stuffed: 0x%02x", c);
+#endif
+		} else if (unlikely(c == PPP_FLAG)) {
+			if (unlikely(inputstate & INS_skip_frame)) {
+				if (!(inputstate & INS_have_data)) { /* 7E 7E */
+					//dbg(DEBUG_HDLC, "(7e)7e------------------------");
+#ifdef CONFIG_GIGASET_DEBUG
+					++bcs->emptycount;
+#endif
+				} else
+					dbg(DEBUG_HDLC,
+					    "7e----------------------------");
+
+				/* end of frame */
+				error = 1;
+				gigaset_rcv_error(NULL, cs, bcs);
+			} else if (!(inputstate & INS_have_data)) { /* 7E 7E */
+				//dbg(DEBUG_HDLC, "(7e)7e------------------------");
+#ifdef CONFIG_GIGASET_DEBUG
+				++bcs->emptycount;
+#endif
+				break;
+			} else {
+				dbg(DEBUG_HDLC,
+				    "7e----------------------------");
+
+				/* end of frame */
+				error = 0;
+
+				if (unlikely(fcs != PPP_GOODFCS)) {
+					err("Packet checksum at %lu failed, "
+					    "packet is corrupted (%u bytes)!",
+					    bcs->rcvbytes, skb->len);
+					compskb = NULL;
+					gigaset_rcv_error(compskb, cs, bcs);
+					error = 1;
+				} else {
+					if (likely((l = skb->len) > 2)) {
+						skb->tail -= 2;
+						skb->len -= 2;
+					} else {
+						dev_kfree_skb(skb);
+						skb = NULL;
+						inputstate |= INS_skip_frame;
+						if (l == 1) {
+							err("invalid packet size (1)!");
+							error = 1;
+							gigaset_rcv_error(NULL, cs, bcs);
+						}
+					}
+					if (likely(!(error ||
+						     (inputstate &
+						      INS_skip_frame)))) {
+						gigaset_rcv_skb(skb, cs, bcs);
+					}
+				}
+			}
+
+			if (unlikely(error))
+				if (skb)
+					dev_kfree_skb(skb);
+
+			fcs = PPP_INITFCS;
+			inputstate &= ~(INS_have_data | INS_skip_frame);
+			if (unlikely(bcs->ignore)) {
+				inputstate |= INS_skip_frame;
+				skb = NULL;
+			} else if (likely((skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN)) != NULL)) {
+				skb_reserve(skb, HW_HDR_LEN);
+			} else {
+				warn("could not allocate new skb");
+				inputstate |= INS_skip_frame;
+			}
+
+			break;
+#ifdef CONFIG_GIGASET_DEBUG
+		} else if (unlikely(muststuff(c))) {
+			/* Should not happen. Possible after ZDLE=1<CR><LF>. */
+			dbg(DEBUG_HDLC, "not byte stuffed: 0x%02x", c);
+#endif
+		}
+
+		/* add character */
+
+#ifdef CONFIG_GIGASET_DEBUG
+		if (unlikely(!(inputstate & INS_have_data))) {
+			dbg(DEBUG_HDLC,
+			    "7e (%d x) ================", bcs->emptycount);
+			bcs->emptycount = 0;
+		}
+#endif
+
+		inputstate |= INS_have_data;
+
+		if (likely(!(inputstate & INS_skip_frame))) {
+			if (unlikely(skb->len == SBUFSIZE)) {
+				warn("received packet too long");
+				dev_kfree_skb_any(skb);
+				skb = NULL;
+				inputstate |= INS_skip_frame;
+				break;
+			}
+			*gigaset_skb_put_quick(skb, 1) = c;
+			/* *__skb_put (skb, 1) = c; */
+			fcs = crc_ccitt_byte(fcs, c);
+		}
+
+		if (unlikely(!numbytes))
+			break;
+		c = *src++;
+		--numbytes;
+		if (unlikely(c == DLE_FLAG &&
+			     (cs->dle ||
+			      inbuf->inputstate & INS_DLE_command))) {
+			inbuf->inputstate |= INS_DLE_char;
+			break;
+		}
+	}
+	bcs->inputstate = inputstate;
+	bcs->fcs = fcs;
+	bcs->skb = skb;
+	return startbytes - numbytes;
+}
+
+/* process a block of received bytes in transparent data mode
+ * Invert bytes, undoing byte stuffing and watching for DLE escapes.
+ * If DLE is encountered, return immediately to let the caller handle it.
+ * Return value:
+ *	number of processed bytes
+ *	numbytes (all bytes processed) on error --FIXME
+ */
+static inline int iraw_loop(unsigned char c, unsigned char *src, int numbytes,
+                            struct inbuf_t *inbuf)
+{
+	struct cardstate *cs = inbuf->cs;
+	struct bc_state *bcs = inbuf->bcs;
+	int inputstate;
+	struct sk_buff *skb;
+	int startbytes = numbytes;
+
+	IFNULLRETVAL(bcs, numbytes);
+	inputstate = bcs->inputstate;
+	skb = bcs->skb;
+	IFNULLRETVAL(skb, numbytes);
+
+	for (;;) {
+		/* add character */
+		inputstate |= INS_have_data;
+
+		if (likely(!(inputstate & INS_skip_frame))) {
+			if (unlikely(skb->len == SBUFSIZE)) {
+				//FIXME just pass skb up and allocate a new one
+				warn("received packet too long");
+				dev_kfree_skb_any(skb);
+				skb = NULL;
+				inputstate |= INS_skip_frame;
+				break;
+			}
+			*gigaset_skb_put_quick(skb, 1) = gigaset_invtab[c];
+		}
+
+		if (unlikely(!numbytes))
+			break;
+		c = *src++;
+		--numbytes;
+		if (unlikely(c == DLE_FLAG &&
+			     (cs->dle ||
+			      inbuf->inputstate & INS_DLE_command))) {
+			inbuf->inputstate |= INS_DLE_char;
+			break;
+		}
+	}
+
+	/* pass data up */
+	if (likely(inputstate & INS_have_data)) {
+		if (likely(!(inputstate & INS_skip_frame))) {
+			gigaset_rcv_skb(skb, cs, bcs);
+		}
+		inputstate &= ~(INS_have_data | INS_skip_frame);
+		if (unlikely(bcs->ignore)) {
+			inputstate |= INS_skip_frame;
+			skb = NULL;
+		} else if (likely((skb = dev_alloc_skb(SBUFSIZE + HW_HDR_LEN))
+				  != NULL)) {
+			skb_reserve(skb, HW_HDR_LEN);
+		} else {
+			warn("could not allocate new skb");
+			inputstate |= INS_skip_frame;
+		}
+	}
+
+	bcs->inputstate = inputstate;
+	bcs->skb = skb;
+	return startbytes - numbytes;
+}
+
+/* process a block of data received from the device
+ */
+void gigaset_m10x_input(struct inbuf_t *inbuf)
+{
+	struct cardstate *cs;
+	unsigned tail, head, numbytes;
+	unsigned char *src, c;
+	int procbytes;
+
+	head = atomic_read(&inbuf->head);
+	tail = atomic_read(&inbuf->tail);
+	dbg(DEBUG_INTR, "buffer state: %u -> %u", head, tail);
+
+	if (head != tail) {
+		cs = inbuf->cs;
+		src = inbuf->data + head;
+		numbytes = (head > tail ? RBUFSIZE : tail) - head;
+		dbg(DEBUG_INTR, "processing %u bytes", numbytes);
+
+		while (numbytes) {
+			if (atomic_read(&cs->mstate) == MS_LOCKED) {
+				procbytes = lock_loop(src, numbytes, inbuf);
+				src += procbytes;
+				numbytes -= procbytes;
+			} else {
+				c = *src++;
+				--numbytes;
+				if (c == DLE_FLAG && (cs->dle ||
+				    inbuf->inputstate & INS_DLE_command)) {
+					if (!(inbuf->inputstate & INS_DLE_char)) {
+						inbuf->inputstate |= INS_DLE_char;
+						goto nextbyte;
+					}
+					/* <DLE> <DLE> => <DLE> in data stream */
+					inbuf->inputstate &= ~INS_DLE_char;
+				}
+
+				if (!(inbuf->inputstate & INS_DLE_char)) {
+
+					/* FIXME Einfach je nach Modus Funktionszeiger in cs setzen [hier+hdlc_loop]?  */
+					/* FIXME Spart folgendes "if" und ermoeglicht andere Protokolle */
+					if (inbuf->inputstate & INS_command)
+						procbytes = cmd_loop(c, src, numbytes, inbuf);
+					else if (inbuf->bcs->proto2 == ISDN_PROTO_L2_HDLC)
+						procbytes = hdlc_loop(c, src, numbytes, inbuf);
+					else
+						procbytes = iraw_loop(c, src, numbytes, inbuf);
+
+					src += procbytes;
+					numbytes -= procbytes;
+				} else {  /* DLE-char */
+					inbuf->inputstate &= ~INS_DLE_char;
+					switch (c) {
+					case 'X': /*begin of command*/
+#ifdef CONFIG_GIGASET_DEBUG
+						if (inbuf->inputstate & INS_command)
+							err("received <DLE> 'X' in command mode");
+#endif
+						inbuf->inputstate |=
+							INS_command | INS_DLE_command;
+						break;
+					case '.': /*end of command*/
+#ifdef CONFIG_GIGASET_DEBUG
+						if (!(inbuf->inputstate & INS_command))
+							err("received <DLE> '.' in hdlc mode");
+#endif
+						inbuf->inputstate &= cs->dle ?
+							~(INS_DLE_command|INS_command)
+							: ~INS_DLE_command;
+						break;
+					//case DLE_FLAG: /*DLE_FLAG in data stream*/ /* schon oben behandelt! */
+					default:
+						err("received 0x10 0x%02x!", (int) c);
+						/* FIXME: reset driver?? */
+					}
+				}
+			}
+nextbyte:
+			if (!numbytes) {
+				/* end of buffer, check for wrap */
+				if (head > tail) {
+					head = 0;
+					src = inbuf->data;
+					numbytes = tail;
+				} else {
+					head = tail;
+					break;
+				}
+			}
+		}
+
+		dbg(DEBUG_INTR, "setting head to %u", head);
+		atomic_set(&inbuf->head, head);
+	}
+}
+
+
+/* == data output ========================================================== */
+
+/* Encoding of a PPP packet into an octet stuffed HDLC frame
+ * with FCS, opening and closing flags.
+ * parameters:
+ *	skb	skb containing original packet (freed upon return)
+ *	head	number of headroom bytes to allocate in result skb
+ *	tail	number of tailroom bytes to allocate in result skb
+ * Return value:
+ *	pointer to newly allocated skb containing the result frame
+ */
+static struct sk_buff *HDLC_Encode(struct sk_buff *skb, int head, int tail)
+{
+	struct sk_buff *hdlc_skb;
+	__u16 fcs;
+	unsigned char c;
+	unsigned char *cp;
+	int len;
+	unsigned int stuf_cnt;
+
+	stuf_cnt = 0;
+	fcs = PPP_INITFCS;
+	cp = skb->data;
+	len = skb->len;
+	while (len--) {
+		if (muststuff(*cp))
+			stuf_cnt++;
+		fcs = crc_ccitt_byte(fcs, *cp++);
+	}
+	fcs ^= 0xffff;                 /* complement */
+
+	/* size of new buffer: original size + number of stuffing bytes
+	 * + 2 bytes FCS + 2 stuffing bytes for FCS (if needed) + 2 flag bytes
+	 */
+	hdlc_skb = dev_alloc_skb(skb->len + stuf_cnt + 6 + tail + head);
+	if (!hdlc_skb) {
+		err("unable to allocate memory for HDLC encoding!");
+		dev_kfree_skb(skb);
+		return NULL;
+	}
+	skb_reserve(hdlc_skb, head);
+
+	/* Copy acknowledge request into new skb */
+	memcpy(hdlc_skb->head, skb->head, 2);
+
+	/* Add flag sequence in front of everything.. */
+	*(skb_put(hdlc_skb, 1)) = PPP_FLAG;
+
+	/* Perform byte stuffing while copying data. */
+	while (skb->len--) {
+		if (muststuff(*skb->data)) {
+			*(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
+			*(skb_put(hdlc_skb, 1)) = (*skb->data++) ^ PPP_TRANS;
+		} else
+			*(skb_put(hdlc_skb, 1)) = *skb->data++;
+	}
+
+	/* Finally add FCS (byte stuffed) and flag sequence */
+	c = (fcs & 0x00ff);      /* least significant byte first */
+	if (muststuff(c)) {
+		*(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
+		c ^= PPP_TRANS;
+	}
+	*(skb_put(hdlc_skb, 1)) = c;
+
+	c = ((fcs >> 8) & 0x00ff);
+	if (muststuff(c)) {
+		*(skb_put(hdlc_skb, 1)) = PPP_ESCAPE;
+		c ^= PPP_TRANS;
+	}
+	*(skb_put(hdlc_skb, 1)) = c;
+
+	*(skb_put(hdlc_skb, 1)) = PPP_FLAG;
+
+	dev_kfree_skb(skb);
+	return hdlc_skb;
+}
+
+/* Encoding of a raw packet into an octet stuffed bit inverted frame
+ * parameters:
+ *	skb	skb containing original packet (freed upon return)
+ *	head	number of headroom bytes to allocate in result skb
+ *	tail	number of tailroom bytes to allocate in result skb
+ * Return value:
+ *	pointer to newly allocated skb containing the result frame
+ */
+static struct sk_buff *iraw_encode(struct sk_buff *skb, int head, int tail)
+{
+	struct sk_buff *iraw_skb;
+	unsigned char c;
+	unsigned char *cp;
+	int len;
+
+	/* worst case: every byte must be stuffed */
+	iraw_skb = dev_alloc_skb(2*skb->len + tail + head);
+	if (!iraw_skb) {
+		err("unable to allocate memory for HDLC encoding!");
+		dev_kfree_skb(skb);
+		return NULL;
+	}
+	skb_reserve(iraw_skb, head);
+
+	cp = skb->data;
+	len = skb->len;
+	while (len--) {
+		c = gigaset_invtab[*cp++];
+		if (c == DLE_FLAG)
+			*(skb_put(iraw_skb, 1)) = c;
+		*(skb_put(iraw_skb, 1)) = c;
+	}
+	dev_kfree_skb(skb);
+	return iraw_skb;
+}
+
+/* gigaset_send_skb
+ * called by common.c to queue an skb for sending
+ * and start transmission if necessary
+ * parameters:
+ *	B Channel control structure
+ *	skb
+ * Return value:
+ *	number of bytes accepted for sending
+ *	(skb->len if ok, 0 if out of buffer space)
+ *	or error code (< 0, eg. -EINVAL)
+ */
+int gigaset_m10x_send_skb(struct bc_state *bcs, struct sk_buff *skb)
+{
+	unsigned len;
+
+	IFNULLRETVAL(bcs, -EFAULT);
+	IFNULLRETVAL(skb, -EFAULT);
+	len = skb->len;
+
+	if (bcs->proto2 == ISDN_PROTO_L2_HDLC)
+		skb = HDLC_Encode(skb, HW_HDR_LEN, 0);
+	else
+		skb = iraw_encode(skb, HW_HDR_LEN, 0);
+	if (!skb)
+		return -ENOMEM;
+
+	skb_queue_tail(&bcs->squeue, skb);
+	tasklet_schedule(&bcs->cs->write_tasklet);
+
+	return len;	/* ok so far */
+}