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linux/net/caif/cfdgml.c
Sjur Brændeland 4a9f65f630 caif: performance bugfix - allow radio stack to prioritize packets.
In the CAIF Payload message the Packet Type indication must be set to
    UNCLASSIFIED in order to allow packet prioritization in the modem's
    network stack. Otherwise TCP-Ack is not prioritized in the modems
    transmit queue.

Signed-off-by: Sjur Brændeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2011-04-11 13:15:58 -07:00

118 lines
3.0 KiB
C

/*
* Copyright (C) ST-Ericsson AB 2010
* Author: Sjur Brendeland/sjur.brandeland@stericsson.com
* License terms: GNU General Public License (GPL) version 2
*/
#define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
#include <linux/stddef.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <net/caif/caif_layer.h>
#include <net/caif/cfsrvl.h>
#include <net/caif/cfpkt.h>
#define container_obj(layr) ((struct cfsrvl *) layr)
#define DGM_CMD_BIT 0x80
#define DGM_FLOW_OFF 0x81
#define DGM_FLOW_ON 0x80
#define DGM_MTU 1500
static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt);
static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt);
struct cflayer *cfdgml_create(u8 channel_id, struct dev_info *dev_info)
{
struct cfsrvl *dgm = kmalloc(sizeof(struct cfsrvl), GFP_ATOMIC);
if (!dgm) {
pr_warn("Out of memory\n");
return NULL;
}
caif_assert(offsetof(struct cfsrvl, layer) == 0);
memset(dgm, 0, sizeof(struct cfsrvl));
cfsrvl_init(dgm, channel_id, dev_info, true);
dgm->layer.receive = cfdgml_receive;
dgm->layer.transmit = cfdgml_transmit;
snprintf(dgm->layer.name, CAIF_LAYER_NAME_SZ - 1, "dgm%d", channel_id);
dgm->layer.name[CAIF_LAYER_NAME_SZ - 1] = '\0';
return &dgm->layer;
}
static int cfdgml_receive(struct cflayer *layr, struct cfpkt *pkt)
{
u8 cmd = -1;
u8 dgmhdr[3];
int ret;
caif_assert(layr->up != NULL);
caif_assert(layr->receive != NULL);
caif_assert(layr->ctrlcmd != NULL);
if (cfpkt_extr_head(pkt, &cmd, 1) < 0) {
pr_err("Packet is erroneous!\n");
cfpkt_destroy(pkt);
return -EPROTO;
}
if ((cmd & DGM_CMD_BIT) == 0) {
if (cfpkt_extr_head(pkt, &dgmhdr, 3) < 0) {
pr_err("Packet is erroneous!\n");
cfpkt_destroy(pkt);
return -EPROTO;
}
ret = layr->up->receive(layr->up, pkt);
return ret;
}
switch (cmd) {
case DGM_FLOW_OFF: /* FLOW OFF */
layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_OFF_IND, 0);
cfpkt_destroy(pkt);
return 0;
case DGM_FLOW_ON: /* FLOW ON */
layr->ctrlcmd(layr, CAIF_CTRLCMD_FLOW_ON_IND, 0);
cfpkt_destroy(pkt);
return 0;
default:
cfpkt_destroy(pkt);
pr_info("Unknown datagram control %d (0x%x)\n", cmd, cmd);
return -EPROTO;
}
}
static int cfdgml_transmit(struct cflayer *layr, struct cfpkt *pkt)
{
u8 packet_type;
u32 zero = 0;
struct caif_payload_info *info;
struct cfsrvl *service = container_obj(layr);
int ret;
if (!cfsrvl_ready(service, &ret))
return ret;
/* STE Modem cannot handle more than 1500 bytes datagrams */
if (cfpkt_getlen(pkt) > DGM_MTU)
return -EMSGSIZE;
cfpkt_add_head(pkt, &zero, 3);
packet_type = 0x08; /* B9 set - UNCLASSIFIED */
cfpkt_add_head(pkt, &packet_type, 1);
/* Add info for MUX-layer to route the packet out. */
info = cfpkt_info(pkt);
info->channel_id = service->layer.id;
/* To optimize alignment, we add up the size of CAIF header
* before payload.
*/
info->hdr_len = 4;
info->dev_info = &service->dev_info;
ret = layr->dn->transmit(layr->dn, pkt);
if (ret < 0) {
u32 tmp32;
cfpkt_extr_head(pkt, &tmp32, 4);
}
return ret;
}