Commit 2ec7a802 authored by Daniel Starke's avatar Daniel Starke Committed by Greg Kroah-Hartman
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tty: n_gsm: add parameters used with parameter negotiation 

n_gsm is based on the 3GPP 07.010 and its newer version is the 3GPP 27.010.
See https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=1516


The changes from 07.010 to 27.010 are non-functional. Therefore, I refer to
the newer 27.010 here. Chapter 5.4.6.3.1 describes the encoding of the
parameter negotiation messages.

Add the parameters used there to 'gsm_mux' and 'gsm_dlci' and initialize both
according to the value ranges and recommended defaults defined in chapter 5.7.

Replace the use of the DLC default values from the 'gsm_mux' fields with the DLC
specific values from the 'gsm_dlci' fields where applicable.

Signed-off-by: default avatarDaniel Starke <daniel.starke@siemens.com>
Link: https://lore.kernel.org/r/20221103091743.2119-2-daniel.starke@siemens.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 7a121247

drivers/tty/n_gsm.c

+45 −13
Original line number Diff line number Diff line
@@ -40,6 +40,7 @@ 
#include <linux/tty.h>

#include <linux/ctype.h>

#include <linux/mm.h>

#include <linux/math.h>

#include <linux/string.h>

#include <linux/slab.h>

#include <linux/poll.h>
@@ -75,7 +76,12 @@ module_param(debug, int, 0600); 


#define T1	10		/* 100mS */

#define T2	34		/* 333mS */

#define T3	10		/* 10s */

#define N2	3		/* Retry 3 times */

#define K	2		/* outstanding I frames */



#define MAX_T3 255		/* In seconds. */

#define MAX_WINDOW_SIZE 7	/* Limit of K in error recovery mode. */



/* Use long timers for testing at low speed with debug on */

#ifdef DEBUG_TIMING
@@ -160,7 +166,12 @@ struct gsm_dlci { 
	int prev_adaption;

	u32 modem_rx;		/* Our incoming virtual modem lines */

	u32 modem_tx;		/* Our outgoing modem lines */

	unsigned int mtu;

	bool dead;		/* Refuse re-open */

	/* Configuration */

	u8 prio;		/* Priority */

	u8 ftype;		/* Frame type */

	u8 k;			/* Window size */

	/* Flow control */

	bool throttled;		/* Private copy of throttle state */

	bool constipated;	/* Throttle status for outgoing */
@@ -283,7 +294,9 @@ struct gsm_mux { 
	int adaption;		/* 1 or 2 supported */

	u8 ftype;		/* UI or UIH */

	int t1, t2;		/* Timers in 1/100th of a sec */

	unsigned int t3;	/* Power wake-up timer in seconds. */

	int n2;			/* Retry count */

	u8 k;			/* Window size */



	/* Statistics (not currently exposed) */

	unsigned long bad_fcs;
@@ -1075,12 +1088,12 @@ static int gsm_dlci_data_output(struct gsm_mux *gsm, struct gsm_dlci *dlci) 
		return 0;



	/* MTU/MRU count only the data bits but watch adaption mode */

	if ((len + h) > gsm->mtu)

		len = gsm->mtu - h;

	if ((len + h) > dlci->mtu)

		len = dlci->mtu - h;



	size = len + h;



	msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);

	msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);

	if (!msg)

		return -ENOMEM;

	dp = msg->data;
@@ -1144,19 +1157,19 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm, 
	len = dlci->skb->len + overhead;



	/* MTU/MRU count only the data bits */

	if (len > gsm->mtu) {

	if (len > dlci->mtu) {

		if (dlci->adaption == 3) {

			/* Over long frame, bin it */

			dev_kfree_skb_any(dlci->skb);

			dlci->skb = NULL;

			return 0;

		}

		len = gsm->mtu;

		len = dlci->mtu;

	} else

		last = 1;



	size = len + overhead;

	msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);

	msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);

	if (msg == NULL) {

		skb_queue_tail(&dlci->skb_list, dlci->skb);

		dlci->skb = NULL;
@@ -1213,7 +1226,7 @@ static int gsm_dlci_modem_output(struct gsm_mux *gsm, struct gsm_dlci *dlci, 
		return -EINVAL;

	}



	msg = gsm_data_alloc(gsm, dlci->addr, size, gsm->ftype);

	msg = gsm_data_alloc(gsm, dlci->addr, size, dlci->ftype);

	if (!msg) {

		pr_err("%s: gsm_data_alloc error", __func__);

		return -ENOMEM;
@@ -1338,8 +1351,9 @@ static void gsm_dlci_data_kick(struct gsm_dlci *dlci) 
static int gsm_control_command(struct gsm_mux *gsm, int cmd, const u8 *data,

			       int dlen)

{

	struct gsm_msg *msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);

	struct gsm_msg *msg;



	msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->dlci[0]->ftype);

	if (msg == NULL)

		return -ENOMEM;
@@ -1365,7 +1379,8 @@ static void gsm_control_reply(struct gsm_mux *gsm, int cmd, const u8 *data, 
					int dlen)

{

	struct gsm_msg *msg;

	msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->ftype);



	msg = gsm_data_alloc(gsm, 0, dlen + 2, gsm->dlci[0]->ftype);

	if (msg == NULL)

		return;

	msg->data[0] = (cmd & 0xFE) << 1 | EA;	/* Clear C/R */
@@ -2075,6 +2090,13 @@ static struct gsm_dlci *gsm_dlci_alloc(struct gsm_mux *gsm, int addr) 
	dlci->gsm = gsm;

	dlci->addr = addr;

	dlci->adaption = gsm->adaption;

	dlci->mtu = gsm->mtu;

	if (addr == 0)

		dlci->prio = 0;

	else

		dlci->prio = roundup(addr + 1, 8) - 1;

	dlci->ftype = gsm->ftype;

	dlci->k = gsm->k;

	dlci->state = DLCI_CLOSED;

	if (addr) {

		dlci->data = gsm_dlci_data;
@@ -2650,7 +2672,9 @@ static struct gsm_mux *gsm_alloc_mux(void) 


	gsm->t1 = T1;

	gsm->t2 = T2;

	gsm->t3 = T3;

	gsm->n2 = N2;

	gsm->k = K;

	gsm->ftype = UIH;

	gsm->adaption = 1;

	gsm->encoding = GSM_ADV_OPT;
@@ -2691,7 +2715,7 @@ static void gsm_copy_config_values(struct gsm_mux *gsm, 
	c->initiator = gsm->initiator;

	c->t1 = gsm->t1;

	c->t2 = gsm->t2;

	c->t3 = 0;	/* Not supported */

	c->t3 = gsm->t3;

	c->n2 = gsm->n2;

	if (gsm->ftype == UIH)

		c->i = 1;
@@ -2700,7 +2724,7 @@ static void gsm_copy_config_values(struct gsm_mux *gsm, 
	pr_debug("Ftype %d i %d\n", gsm->ftype, c->i);

	c->mru = gsm->mru;

	c->mtu = gsm->mtu;

	c->k = 0;

	c->k = gsm->k;

}



static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c)
@@ -2717,12 +2741,16 @@ static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c) 
		return -EINVAL;

	if (c->mru > MAX_MRU || c->mtu > MAX_MTU)

		return -EINVAL;

	if (c->t3 > MAX_T3)

		return -EINVAL;

	if (c->n2 > 255)

		return -EINVAL;

	if (c->encapsulation > 1)	/* Basic, advanced, no I */

		return -EINVAL;

	if (c->initiator > 1)

		return -EINVAL;

	if (c->k > MAX_WINDOW_SIZE)

		return -EINVAL;

	if (c->i == 0 || c->i > 2)	/* UIH and UI only */

		return -EINVAL;

	/*
@@ -2770,6 +2798,10 @@ static int gsm_config(struct gsm_mux *gsm, struct gsm_config *c) 
		gsm->t1 = c->t1;

	if (c->t2)

		gsm->t2 = c->t2;

	if (c->t3)

		gsm->t3 = c->t3;

	if (c->k)

		gsm->k = c->k;



	/*

	 * FIXME: We need to separate activation/deactivation from adding
@@ -3298,9 +3330,9 @@ static int gsm_create_network(struct gsm_dlci *dlci, struct gsm_netconfig *nc) 
		pr_err("alloc_netdev failed\n");

		return -ENOMEM;

	}

	net->mtu = dlci->gsm->mtu;

	net->mtu = dlci->mtu;

	net->min_mtu = MIN_MTU;

	net->max_mtu = dlci->gsm->mtu;

	net->max_mtu = dlci->mtu;

	mux_net = netdev_priv(net);

	mux_net->dlci = dlci;

	kref_init(&mux_net->ref);