1 files changed, 606 insertions, 0 deletions

diff --git a/drivers/staging/isdn/gigaset/asyncdata.c b/drivers/staging/isdn/gigaset/asyncdata.c
new file mode 100644
index 000000000000..a34b3c9d8a71
--- /dev/null
+++ b/drivers/staging/isdn/gigaset/asyncdata.c
@@ -0,0 +1,606 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * 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.
+ *
+ * =====================================================================
+ * =====================================================================
+ */
+
+#include "gigaset.h"
+#include <linux/crc-ccitt.h>
+#include <linux/bitrev.h>
+#include <linux/export.h>
+
+/* check if byte must be stuffed/escaped
+ * I'm not sure which data should be encoded.
+ * Therefore I will go the hard way and encode 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
+ * (mstate != MS_LOCKED && (inputstate & INS_command))
+ * Append received bytes to the command response buffer and forward them
+ * line by line to the response handler. Exit whenever a mode/state change
+ * might have occurred.
+ * Note: Received lines may be terminated by CR, LF, or CR LF, which will be
+ * removed before passing the line to the response handler.
+ * Return value:
+ *	number of processed bytes
+ */
+static unsigned cmd_loop(unsigned numbytes, struct inbuf_t *inbuf)
+{
+	unsigned char *src = inbuf->data + inbuf->head;
+	struct cardstate *cs = inbuf->cs;
+	unsigned cbytes = cs->cbytes;
+	unsigned procbytes = 0;
+	unsigned char c;
+
+	while (procbytes < numbytes) {
+		c = *src++;
+		procbytes++;
+
+		switch (c) {
+		case '\n':
+			if (cbytes == 0 && cs->respdata[0] == '\r') {
+				/* collapse LF with preceding CR */
+				cs->respdata[0] = 0;
+				break;
+			}
+			/* fall through */
+		case '\r':
+			/* end of message line, pass to response handler */
+			if (cbytes >= MAX_RESP_SIZE) {
+				dev_warn(cs->dev, "response too large (%d)\n",
+					 cbytes);
+				cbytes = MAX_RESP_SIZE;
+			}
+			cs->cbytes = cbytes;
+			gigaset_dbg_buffer(DEBUG_TRANSCMD, "received response",
+					   cbytes, cs->respdata);
+			gigaset_handle_modem_response(cs);
+			cbytes = 0;
+
+			/* store EOL byte for CRLF collapsing */
+			cs->respdata[0] = c;
+
+			/* cs->dle may have changed */
+			if (cs->dle && !(inbuf->inputstate & INS_DLE_command))
+				inbuf->inputstate &= ~INS_command;
+
+			/* return for reevaluating state */
+			goto exit;
+
+		case DLE_FLAG:
+			if (inbuf->inputstate & INS_DLE_char) {
+				/* quoted DLE: clear quote flag */
+				inbuf->inputstate &= ~INS_DLE_char;
+			} else if (cs->dle ||
+				   (inbuf->inputstate & INS_DLE_command)) {
+				/* DLE escape, pass up for handling */
+				inbuf->inputstate |= INS_DLE_char;
+				goto exit;
+			}
+			/* quoted or not in DLE mode: treat as regular data */
+			/* fall through */
+		default:
+			/* append to line buffer if possible */
+			if (cbytes < MAX_RESP_SIZE)
+				cs->respdata[cbytes] = c;
+			cbytes++;
+		}
+	}
+exit:
+	cs->cbytes = cbytes;
+	return procbytes;
+}
+
+/* process a block of received bytes in lock mode
+ * All received bytes are passed unmodified to the tty i/f.
+ * Return value:
+ *	number of processed bytes
+ */
+static unsigned lock_loop(unsigned numbytes, struct inbuf_t *inbuf)
+{
+	unsigned char *src = inbuf->data + inbuf->head;
+
+	gigaset_dbg_buffer(DEBUG_LOCKCMD, "received response", numbytes, src);
+	gigaset_if_receive(inbuf->cs, src, numbytes);
+	return numbytes;
+}
+
+/* process a block of received bytes in HDLC data mode
+ * (mstate != MS_LOCKED && !(inputstate & INS_command) && proto2 == L2_HDLC)
+ * 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
+ */
+static unsigned hdlc_loop(unsigned numbytes, struct inbuf_t *inbuf)
+{
+	struct cardstate *cs = inbuf->cs;
+	struct bc_state *bcs = cs->bcs;
+	int inputstate = bcs->inputstate;
+	__u16 fcs = bcs->rx_fcs;
+	struct sk_buff *skb = bcs->rx_skb;
+	unsigned char *src = inbuf->data + inbuf->head;
+	unsigned procbytes = 0;
+	unsigned char c;
+
+	if (inputstate & INS_byte_stuff) {
+		if (!numbytes)
+			return 0;
+		inputstate &= ~INS_byte_stuff;
+		goto byte_stuff;
+	}
+
+	while (procbytes < numbytes) {
+		c = *src++;
+		procbytes++;
+		if (c == DLE_FLAG) {
+			if (inputstate & INS_DLE_char) {
+				/* quoted DLE: clear quote flag */
+				inputstate &= ~INS_DLE_char;
+			} else if (cs->dle || (inputstate & INS_DLE_command)) {
+				/* DLE escape, pass up for handling */
+				inputstate |= INS_DLE_char;
+				break;
+			}
+		}
+
+		if (c == PPP_ESCAPE) {
+			/* byte stuffing indicator: pull in next byte */
+			if (procbytes >= numbytes) {
+				/* end of buffer, save for later processing */
+				inputstate |= INS_byte_stuff;
+				break;
+			}
+byte_stuff:
+			c = *src++;
+			procbytes++;
+			if (c == DLE_FLAG) {
+				if (inputstate & INS_DLE_char) {
+					/* quoted DLE: clear quote flag */
+					inputstate &= ~INS_DLE_char;
+				} else if (cs->dle ||
+					   (inputstate & INS_DLE_command)) {
+					/* DLE escape, pass up for handling */
+					inputstate |=
+						INS_DLE_char | INS_byte_stuff;
+					break;
+				}
+			}
+			c ^= PPP_TRANS;
+#ifdef CONFIG_GIGASET_DEBUG
+			if (!muststuff(c))
+				gig_dbg(DEBUG_HDLC, "byte stuffed: 0x%02x", c);
+#endif
+		} else if (c == PPP_FLAG) {
+			/* end of frame: process content if any */
+			if (inputstate & INS_have_data) {
+				gig_dbg(DEBUG_HDLC,
+					"7e----------------------------");
+
+				/* check and pass received frame */
+				if (!skb) {
+					/* skipped frame */
+					gigaset_isdn_rcv_err(bcs);
+				} else if (skb->len < 2) {
+					/* frame too short for FCS */
+					dev_warn(cs->dev,
+						 "short frame (%d)\n",
+						 skb->len);
+					gigaset_isdn_rcv_err(bcs);
+					dev_kfree_skb_any(skb);
+				} else if (fcs != PPP_GOODFCS) {
+					/* frame check error */
+					dev_err(cs->dev,
+						"Checksum failed, %u bytes corrupted!\n",
+						skb->len);
+					gigaset_isdn_rcv_err(bcs);
+					dev_kfree_skb_any(skb);
+				} else {
+					/* good frame */
+					__skb_trim(skb, skb->len - 2);
+					gigaset_skb_rcvd(bcs, skb);
+				}
+
+				/* prepare reception of next frame */
+				inputstate &= ~INS_have_data;
+				skb = gigaset_new_rx_skb(bcs);
+			} else {
+				/* empty frame (7E 7E) */
+#ifdef CONFIG_GIGASET_DEBUG
+				++bcs->emptycount;
+#endif
+				if (!skb) {
+					/* skipped (?) */
+					gigaset_isdn_rcv_err(bcs);
+					skb = gigaset_new_rx_skb(bcs);
+				}
+			}
+
+			fcs = PPP_INITFCS;
+			continue;
+#ifdef CONFIG_GIGASET_DEBUG
+		} else if (muststuff(c)) {
+			/* Should not happen. Possible after ZDLE=1<CR><LF>. */
+			gig_dbg(DEBUG_HDLC, "not byte stuffed: 0x%02x", c);
+#endif
+		}
+
+		/* regular data byte, append to skb */
+#ifdef CONFIG_GIGASET_DEBUG
+		if (!(inputstate & INS_have_data)) {
+			gig_dbg(DEBUG_HDLC, "7e (%d x) ================",
+				bcs->emptycount);
+			bcs->emptycount = 0;
+		}
+#endif
+		inputstate |= INS_have_data;
+		if (skb) {
+			if (skb->len >= bcs->rx_bufsize) {
+				dev_warn(cs->dev, "received packet too long\n");
+				dev_kfree_skb_any(skb);
+				/* skip remainder of packet */
+				bcs->rx_skb = skb = NULL;
+			} else {
+				__skb_put_u8(skb, c);
+				fcs = crc_ccitt_byte(fcs, c);
+			}
+		}
+	}
+
+	bcs->inputstate = inputstate;
+	bcs->rx_fcs = fcs;
+	return procbytes;
+}
+
+/* process a block of received bytes in transparent data mode
+ * (mstate != MS_LOCKED && !(inputstate & INS_command) && proto2 != L2_HDLC)
+ * 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
+ */
+static unsigned iraw_loop(unsigned numbytes, struct inbuf_t *inbuf)
+{
+	struct cardstate *cs = inbuf->cs;
+	struct bc_state *bcs = cs->bcs;
+	int inputstate = bcs->inputstate;
+	struct sk_buff *skb = bcs->rx_skb;
+	unsigned char *src = inbuf->data + inbuf->head;
+	unsigned procbytes = 0;
+	unsigned char c;
+
+	if (!skb) {
+		/* skip this block */
+		gigaset_new_rx_skb(bcs);
+		return numbytes;
+	}
+
+	while (procbytes < numbytes && skb->len < bcs->rx_bufsize) {
+		c = *src++;
+		procbytes++;
+
+		if (c == DLE_FLAG) {
+			if (inputstate & INS_DLE_char) {
+				/* quoted DLE: clear quote flag */
+				inputstate &= ~INS_DLE_char;
+			} else if (cs->dle || (inputstate & INS_DLE_command)) {
+				/* DLE escape, pass up for handling */
+				inputstate |= INS_DLE_char;
+				break;
+			}
+		}
+
+		/* regular data byte: append to current skb */
+		inputstate |= INS_have_data;
+		__skb_put_u8(skb, bitrev8(c));
+	}
+
+	/* pass data up */
+	if (inputstate & INS_have_data) {
+		gigaset_skb_rcvd(bcs, skb);
+		inputstate &= ~INS_have_data;
+		gigaset_new_rx_skb(bcs);
+	}
+
+	bcs->inputstate = inputstate;
+	return procbytes;
+}
+
+/* process DLE escapes
+ * Called whenever a DLE sequence might be encountered in the input stream.
+ * Either processes the entire DLE sequence or, if that isn't possible,
+ * notes the fact that an initial DLE has been received in the INS_DLE_char
+ * inputstate flag and resumes processing of the sequence on the next call.
+ */
+static void handle_dle(struct inbuf_t *inbuf)
+{
+	struct cardstate *cs = inbuf->cs;
+
+	if (cs->mstate == MS_LOCKED)
+		return;		/* no DLE processing in lock mode */
+
+	if (!(inbuf->inputstate & INS_DLE_char)) {
+		/* no DLE pending */
+		if (inbuf->data[inbuf->head] == DLE_FLAG &&
+		    (cs->dle || inbuf->inputstate & INS_DLE_command)) {
+			/* start of DLE sequence */
+			inbuf->head++;
+			if (inbuf->head == inbuf->tail ||
+			    inbuf->head == RBUFSIZE) {
+				/* end of buffer, save for later processing */
+				inbuf->inputstate |= INS_DLE_char;
+				return;
+			}
+		} else {
+			/* regular data byte */
+			return;
+		}
+	}
+
+	/* consume pending DLE */
+	inbuf->inputstate &= ~INS_DLE_char;
+
+	switch (inbuf->data[inbuf->head]) {
+	case 'X':	/* begin of event message */
+		if (inbuf->inputstate & INS_command)
+			dev_notice(cs->dev,
+				   "received <DLE>X in command mode\n");
+		inbuf->inputstate |= INS_command | INS_DLE_command;
+		inbuf->head++;	/* byte consumed */
+		break;
+	case '.':	/* end of event message */
+		if (!(inbuf->inputstate & INS_DLE_command))
+			dev_notice(cs->dev,
+				   "received <DLE>. without <DLE>X\n");
+		inbuf->inputstate &= ~INS_DLE_command;
+		/* return to data mode if in DLE mode */
+		if (cs->dle)
+			inbuf->inputstate &= ~INS_command;
+		inbuf->head++;	/* byte consumed */
+		break;
+	case DLE_FLAG:	/* DLE in data stream */
+		/* mark as quoted */
+		inbuf->inputstate |= INS_DLE_char;
+		if (!(cs->dle || inbuf->inputstate & INS_DLE_command))
+			dev_notice(cs->dev,
+				   "received <DLE><DLE> not in DLE mode\n");
+		break;	/* quoted byte left in buffer */
+	default:
+		dev_notice(cs->dev, "received <DLE><%02x>\n",
+			   inbuf->data[inbuf->head]);
+		/* quoted byte left in buffer */
+	}
+}
+
+/**
+ * gigaset_m10x_input() - process a block of data received from the device
+ * @inbuf:	received data and device descriptor structure.
+ *
+ * Called by hardware module {ser,usb}_gigaset with a block of received
+ * bytes. Separates the bytes received over the serial data channel into
+ * user data and command replies (locked/unlocked) according to the
+ * current state of the interface.
+ */
+void gigaset_m10x_input(struct inbuf_t *inbuf)
+{
+	struct cardstate *cs = inbuf->cs;
+	unsigned numbytes, procbytes;
+
+	gig_dbg(DEBUG_INTR, "buffer state: %u -> %u", inbuf->head, inbuf->tail);
+
+	while (inbuf->head != inbuf->tail) {
+		/* check for DLE escape */
+		handle_dle(inbuf);
+
+		/* process a contiguous block of bytes */
+		numbytes = (inbuf->head > inbuf->tail ?
+			    RBUFSIZE : inbuf->tail) - inbuf->head;
+		gig_dbg(DEBUG_INTR, "processing %u bytes", numbytes);
+		/*
+		 * numbytes may be 0 if handle_dle() ate the last byte.
+		 * This does no harm, *_loop() will just return 0 immediately.
+		 */
+
+		if (cs->mstate == MS_LOCKED)
+			procbytes = lock_loop(numbytes, inbuf);
+		else if (inbuf->inputstate & INS_command)
+			procbytes = cmd_loop(numbytes, inbuf);
+		else if (cs->bcs->proto2 == L2_HDLC)
+			procbytes = hdlc_loop(numbytes, inbuf);
+		else
+			procbytes = iraw_loop(numbytes, inbuf);
+		inbuf->head += procbytes;
+
+		/* check for buffer wraparound */
+		if (inbuf->head >= RBUFSIZE)
+			inbuf->head = 0;
+
+		gig_dbg(DEBUG_INTR, "head set to %u", inbuf->head);
+	}
+}
+EXPORT_SYMBOL_GPL(gigaset_m10x_input);
+
+
+/* == data output ========================================================== */
+
+/*
+ * Encode a data packet into an octet stuffed HDLC frame with FCS,
+ * opening and closing flags, preserving headroom data.
+ * parameters:
+ *	skb		skb containing original packet (freed upon return)
+ * Return value:
+ *	pointer to newly allocated skb containing the result frame
+ *	and the original link layer header, NULL on error
+ */
+static struct sk_buff *HDLC_Encode(struct sk_buff *skb)
+{
+	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
+	 * + room for link layer header
+	 */
+	hdlc_skb = dev_alloc_skb(skb->len + stuf_cnt + 6 + skb->mac_len);
+	if (!hdlc_skb) {
+		dev_kfree_skb_any(skb);
+		return NULL;
+	}
+
+	/* Copy link layer header into new skb */
+	skb_reset_mac_header(hdlc_skb);
+	skb_reserve(hdlc_skb, skb->mac_len);
+	memcpy(skb_mac_header(hdlc_skb), skb_mac_header(skb), skb->mac_len);
+	hdlc_skb->mac_len = skb->mac_len;
+
+	/* Add flag sequence in front of everything.. */
+	skb_put_u8(hdlc_skb, PPP_FLAG);
+
+	/* Perform byte stuffing while copying data. */
+	while (skb->len--) {
+		if (muststuff(*skb->data)) {
+			skb_put_u8(hdlc_skb, PPP_ESCAPE);
+			skb_put_u8(hdlc_skb, (*skb->data++) ^ PPP_TRANS);
+		} else
+			skb_put_u8(hdlc_skb, *skb->data++);
+	}
+
+	/* Finally add FCS (byte stuffed) and flag sequence */
+	c = (fcs & 0x00ff);	/* least significant byte first */
+	if (muststuff(c)) {
+		skb_put_u8(hdlc_skb, PPP_ESCAPE);
+		c ^= PPP_TRANS;
+	}
+	skb_put_u8(hdlc_skb, c);
+
+	c = ((fcs >> 8) & 0x00ff);
+	if (muststuff(c)) {
+		skb_put_u8(hdlc_skb, PPP_ESCAPE);
+		c ^= PPP_TRANS;
+	}
+	skb_put_u8(hdlc_skb, c);
+
+	skb_put_u8(hdlc_skb, PPP_FLAG);
+
+	dev_kfree_skb_any(skb);
+	return hdlc_skb;
+}
+
+/*
+ * Encode a data packet into an octet stuffed raw bit inverted frame,
+ * preserving headroom data.
+ * parameters:
+ *	skb		skb containing original packet (freed upon return)
+ * Return value:
+ *	pointer to newly allocated skb containing the result frame
+ *	and the original link layer header, NULL on error
+ */
+static struct sk_buff *iraw_encode(struct sk_buff *skb)
+{
+	struct sk_buff *iraw_skb;
+	unsigned char c;
+	unsigned char *cp;
+	int len;
+
+	/* size of new buffer (worst case = every byte must be stuffed):
+	 * 2 * original size + room for link layer header
+	 */
+	iraw_skb = dev_alloc_skb(2 * skb->len + skb->mac_len);
+	if (!iraw_skb) {
+		dev_kfree_skb_any(skb);
+		return NULL;
+	}
+
+	/* copy link layer header into new skb */
+	skb_reset_mac_header(iraw_skb);
+	skb_reserve(iraw_skb, skb->mac_len);
+	memcpy(skb_mac_header(iraw_skb), skb_mac_header(skb), skb->mac_len);
+	iraw_skb->mac_len = skb->mac_len;
+
+	/* copy and stuff data */
+	cp = skb->data;
+	len = skb->len;
+	while (len--) {
+		c = bitrev8(*cp++);
+		if (c == DLE_FLAG)
+			skb_put_u8(iraw_skb, c);
+		skb_put_u8(iraw_skb, c);
+	}
+	dev_kfree_skb_any(skb);
+	return iraw_skb;
+}
+
+/**
+ * gigaset_m10x_send_skb() - queue an skb for sending
+ * @bcs:	B channel descriptor structure.
+ * @skb:	data to send.
+ *
+ * Called by LL to encode and queue an skb for sending, and start
+ * transmission if necessary.
+ * Once the payload data has been transmitted completely, gigaset_skb_sent()
+ * will be called with the skb's link layer header preserved.
+ *
+ * Return value:
+ *	number of bytes accepted for sending (skb->len) if ok,
+ *	error code < 0 (eg. -ENOMEM) on error
+ */
+int gigaset_m10x_send_skb(struct bc_state *bcs, struct sk_buff *skb)
+{
+	struct cardstate *cs = bcs->cs;
+	unsigned len = skb->len;
+	unsigned long flags;
+
+	if (bcs->proto2 == L2_HDLC)
+		skb = HDLC_Encode(skb);
+	else
+		skb = iraw_encode(skb);
+	if (!skb) {
+		dev_err(cs->dev,
+			"unable to allocate memory for encoding!\n");
+		return -ENOMEM;
+	}
+
+	skb_queue_tail(&bcs->squeue, skb);
+	spin_lock_irqsave(&cs->lock, flags);
+	if (cs->connected)
+		tasklet_schedule(&cs->write_tasklet);
+	spin_unlock_irqrestore(&cs->lock, flags);
+
+	return len;	/* ok so far */
+}
+EXPORT_SYMBOL_GPL(gigaset_m10x_send_skb);