linux/net/nfc/digital_core.c
Thierry Escande 59ee2361c9 NFC Digital: Implement driver commands mechanism
This implements the mechanism used to send commands to the driver in
initiator mode through in_send_cmd().

Commands are serialized and sent to the driver by using a work item
on the system workqueue. Responses are handled asynchronously by
another work item. Once the digital stack receives the response through
the command_complete callback, the next command is sent to the driver.

This also implements the polling mechanism. It's handled by a work item
cycling on all supported protocols. The start poll command for a given
protocol is sent to the driver using the mechanism described above.
The process continues until a peer is discovered or stop_poll is
called. This patch implements the poll function for NFC-A that sends a
SENS_REQ command and waits for the SENS_RES response.

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2013-09-25 02:02:07 +02:00

478 lines
11 KiB
C

/*
* NFC Digital Protocol stack
* Copyright (c) 2013, Intel Corporation.
*
* This program is free software; you can redistribute it and/or modify it
* under the terms and conditions of the GNU General Public License,
* version 2, as published by the Free Software Foundation.
*
* This program is distributed in the hope it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*
*/
#include <linux/module.h>
#include "digital.h"
#define DIGITAL_PROTO_NFCA_RF_TECH \
(NFC_PROTO_JEWEL_MASK | NFC_PROTO_MIFARE_MASK)
struct digital_cmd {
struct list_head queue;
u8 type;
u8 pending;
u16 timeout;
struct sk_buff *req;
struct sk_buff *resp;
nfc_digital_cmd_complete_t cmd_cb;
void *cb_context;
};
struct sk_buff *digital_skb_alloc(struct nfc_digital_dev *ddev,
unsigned int len)
{
struct sk_buff *skb;
skb = alloc_skb(len + ddev->tx_headroom + ddev->tx_tailroom,
GFP_KERNEL);
if (skb)
skb_reserve(skb, ddev->tx_headroom);
return skb;
}
static inline void digital_switch_rf(struct nfc_digital_dev *ddev, bool on)
{
ddev->ops->switch_rf(ddev, on);
}
static inline void digital_abort_cmd(struct nfc_digital_dev *ddev)
{
ddev->ops->abort_cmd(ddev);
}
static void digital_wq_cmd_complete(struct work_struct *work)
{
struct digital_cmd *cmd;
struct nfc_digital_dev *ddev = container_of(work,
struct nfc_digital_dev,
cmd_complete_work);
mutex_lock(&ddev->cmd_lock);
cmd = list_first_entry_or_null(&ddev->cmd_queue, struct digital_cmd,
queue);
if (!cmd) {
mutex_unlock(&ddev->cmd_lock);
return;
}
list_del(&cmd->queue);
mutex_unlock(&ddev->cmd_lock);
if (!IS_ERR(cmd->resp))
print_hex_dump_debug("DIGITAL RX: ", DUMP_PREFIX_NONE, 16, 1,
cmd->resp->data, cmd->resp->len, false);
cmd->cmd_cb(ddev, cmd->cb_context, cmd->resp);
kfree(cmd);
schedule_work(&ddev->cmd_work);
}
static void digital_send_cmd_complete(struct nfc_digital_dev *ddev,
void *arg, struct sk_buff *resp)
{
struct digital_cmd *cmd = arg;
cmd->resp = resp;
schedule_work(&ddev->cmd_complete_work);
}
static void digital_wq_cmd(struct work_struct *work)
{
int rc;
struct digital_cmd *cmd;
struct nfc_digital_dev *ddev = container_of(work,
struct nfc_digital_dev,
cmd_work);
mutex_lock(&ddev->cmd_lock);
cmd = list_first_entry_or_null(&ddev->cmd_queue, struct digital_cmd,
queue);
if (!cmd || cmd->pending) {
mutex_unlock(&ddev->cmd_lock);
return;
}
mutex_unlock(&ddev->cmd_lock);
if (cmd->req)
print_hex_dump_debug("DIGITAL TX: ", DUMP_PREFIX_NONE, 16, 1,
cmd->req->data, cmd->req->len, false);
switch (cmd->type) {
case DIGITAL_CMD_IN_SEND:
rc = ddev->ops->in_send_cmd(ddev, cmd->req, cmd->timeout,
digital_send_cmd_complete, cmd);
break;
default:
PR_ERR("Unknown cmd type %d", cmd->type);
return;
}
if (!rc)
return;
PR_ERR("in_send_command returned err %d", rc);
mutex_lock(&ddev->cmd_lock);
list_del(&cmd->queue);
mutex_unlock(&ddev->cmd_lock);
kfree_skb(cmd->req);
kfree(cmd);
schedule_work(&ddev->cmd_work);
}
int digital_send_cmd(struct nfc_digital_dev *ddev, u8 cmd_type,
struct sk_buff *skb, u16 timeout,
nfc_digital_cmd_complete_t cmd_cb, void *cb_context)
{
struct digital_cmd *cmd;
cmd = kzalloc(sizeof(struct digital_cmd), GFP_KERNEL);
if (!cmd)
return -ENOMEM;
cmd->type = cmd_type;
cmd->timeout = timeout;
cmd->req = skb;
cmd->cmd_cb = cmd_cb;
cmd->cb_context = cb_context;
INIT_LIST_HEAD(&cmd->queue);
mutex_lock(&ddev->cmd_lock);
list_add_tail(&cmd->queue, &ddev->cmd_queue);
mutex_unlock(&ddev->cmd_lock);
schedule_work(&ddev->cmd_work);
return 0;
}
int digital_in_configure_hw(struct nfc_digital_dev *ddev, int type, int param)
{
int rc;
rc = ddev->ops->in_configure_hw(ddev, type, param);
if (rc)
PR_ERR("in_configure_hw failed: %d", rc);
return rc;
}
void digital_poll_next_tech(struct nfc_digital_dev *ddev)
{
digital_switch_rf(ddev, 0);
mutex_lock(&ddev->poll_lock);
if (!ddev->poll_tech_count) {
mutex_unlock(&ddev->poll_lock);
return;
}
ddev->poll_tech_index = (ddev->poll_tech_index + 1) %
ddev->poll_tech_count;
mutex_unlock(&ddev->poll_lock);
schedule_work(&ddev->poll_work);
}
static void digital_wq_poll(struct work_struct *work)
{
int rc;
struct digital_poll_tech *poll_tech;
struct nfc_digital_dev *ddev = container_of(work,
struct nfc_digital_dev,
poll_work);
mutex_lock(&ddev->poll_lock);
if (!ddev->poll_tech_count) {
mutex_unlock(&ddev->poll_lock);
return;
}
poll_tech = &ddev->poll_techs[ddev->poll_tech_index];
mutex_unlock(&ddev->poll_lock);
rc = poll_tech->poll_func(ddev, poll_tech->rf_tech);
if (rc)
digital_poll_next_tech(ddev);
}
static void digital_add_poll_tech(struct nfc_digital_dev *ddev, u8 rf_tech,
digital_poll_t poll_func)
{
struct digital_poll_tech *poll_tech;
if (ddev->poll_tech_count >= NFC_DIGITAL_POLL_MODE_COUNT_MAX)
return;
poll_tech = &ddev->poll_techs[ddev->poll_tech_count++];
poll_tech->rf_tech = rf_tech;
poll_tech->poll_func = poll_func;
}
/**
* start_poll operation
*
* For every supported protocol, the corresponding polling function is added
* to the table of polling technologies (ddev->poll_techs[]) using
* digital_add_poll_tech().
* When a polling function fails (by timeout or protocol error) the next one is
* schedule by digital_poll_next_tech() on the poll workqueue (ddev->poll_work).
*/
static int digital_start_poll(struct nfc_dev *nfc_dev, __u32 im_protocols,
__u32 tm_protocols)
{
struct nfc_digital_dev *ddev = nfc_get_drvdata(nfc_dev);
u32 matching_im_protocols, matching_tm_protocols;
PR_DBG("protocols: im 0x%x, tm 0x%x, supported 0x%x", im_protocols,
tm_protocols, ddev->protocols);
matching_im_protocols = ddev->protocols & im_protocols;
matching_tm_protocols = ddev->protocols & tm_protocols;
if (!matching_im_protocols && !matching_tm_protocols) {
PR_ERR("No known protocol");
return -EINVAL;
}
if (ddev->poll_tech_count) {
PR_ERR("Already polling");
return -EBUSY;
}
if (ddev->curr_protocol) {
PR_ERR("A target is already active");
return -EBUSY;
}
ddev->poll_tech_count = 0;
ddev->poll_tech_index = 0;
if (matching_im_protocols & DIGITAL_PROTO_NFCA_RF_TECH)
digital_add_poll_tech(ddev, NFC_DIGITAL_RF_TECH_106A,
digital_in_send_sens_req);
if (!ddev->poll_tech_count) {
PR_ERR("Unsupported protocols: im=0x%x, tm=0x%x",
matching_im_protocols, matching_tm_protocols);
return -EINVAL;
}
schedule_work(&ddev->poll_work);
return 0;
}
static void digital_stop_poll(struct nfc_dev *nfc_dev)
{
struct nfc_digital_dev *ddev = nfc_get_drvdata(nfc_dev);
mutex_lock(&ddev->poll_lock);
if (!ddev->poll_tech_count) {
PR_ERR("Polling operation was not running");
mutex_unlock(&ddev->poll_lock);
return;
}
ddev->poll_tech_count = 0;
mutex_unlock(&ddev->poll_lock);
cancel_work_sync(&ddev->poll_work);
digital_abort_cmd(ddev);
}
static int digital_dev_up(struct nfc_dev *nfc_dev)
{
struct nfc_digital_dev *ddev = nfc_get_drvdata(nfc_dev);
digital_switch_rf(ddev, 1);
return 0;
}
static int digital_dev_down(struct nfc_dev *nfc_dev)
{
struct nfc_digital_dev *ddev = nfc_get_drvdata(nfc_dev);
digital_switch_rf(ddev, 0);
return 0;
}
static int digital_dep_link_up(struct nfc_dev *nfc_dev,
struct nfc_target *target,
__u8 comm_mode, __u8 *gb, size_t gb_len)
{
return -EOPNOTSUPP;
}
static int digital_dep_link_down(struct nfc_dev *nfc_dev)
{
return -EOPNOTSUPP;
}
static int digital_activate_target(struct nfc_dev *nfc_dev,
struct nfc_target *target, __u32 protocol)
{
return 0;
}
static void digital_deactivate_target(struct nfc_dev *nfc_dev,
struct nfc_target *target)
{
struct nfc_digital_dev *ddev = nfc_get_drvdata(nfc_dev);
ddev->curr_protocol = 0;
}
static int digital_tg_send(struct nfc_dev *dev, struct sk_buff *skb)
{
return -EOPNOTSUPP;
}
static int digital_in_send(struct nfc_dev *nfc_dev, struct nfc_target *target,
struct sk_buff *skb, data_exchange_cb_t cb,
void *cb_context)
{
return -EOPNOTSUPP;
}
static struct nfc_ops digital_nfc_ops = {
.dev_up = digital_dev_up,
.dev_down = digital_dev_down,
.start_poll = digital_start_poll,
.stop_poll = digital_stop_poll,
.dep_link_up = digital_dep_link_up,
.dep_link_down = digital_dep_link_down,
.activate_target = digital_activate_target,
.deactivate_target = digital_deactivate_target,
.tm_send = digital_tg_send,
.im_transceive = digital_in_send,
};
struct nfc_digital_dev *nfc_digital_allocate_device(struct nfc_digital_ops *ops,
__u32 supported_protocols,
__u32 driver_capabilities,
int tx_headroom, int tx_tailroom)
{
struct nfc_digital_dev *ddev;
if (!ops->in_configure_hw || !ops->in_send_cmd || !ops->tg_listen ||
!ops->tg_configure_hw || !ops->tg_send_cmd || !ops->abort_cmd ||
!ops->switch_rf)
return NULL;
ddev = kzalloc(sizeof(struct nfc_digital_dev), GFP_KERNEL);
if (!ddev) {
PR_ERR("kzalloc failed");
return NULL;
}
ddev->driver_capabilities = driver_capabilities;
ddev->ops = ops;
mutex_init(&ddev->cmd_lock);
INIT_LIST_HEAD(&ddev->cmd_queue);
INIT_WORK(&ddev->cmd_work, digital_wq_cmd);
INIT_WORK(&ddev->cmd_complete_work, digital_wq_cmd_complete);
mutex_init(&ddev->poll_lock);
INIT_WORK(&ddev->poll_work, digital_wq_poll);
if (supported_protocols & NFC_PROTO_JEWEL_MASK)
ddev->protocols |= NFC_PROTO_JEWEL_MASK;
if (supported_protocols & NFC_PROTO_MIFARE_MASK)
ddev->protocols |= NFC_PROTO_MIFARE_MASK;
ddev->tx_headroom = tx_headroom + DIGITAL_MAX_HEADER_LEN;
ddev->tx_tailroom = tx_tailroom + DIGITAL_CRC_LEN;
ddev->nfc_dev = nfc_allocate_device(&digital_nfc_ops, ddev->protocols,
ddev->tx_headroom,
ddev->tx_tailroom);
if (!ddev->nfc_dev) {
PR_ERR("nfc_allocate_device failed");
goto free_dev;
}
nfc_set_drvdata(ddev->nfc_dev, ddev);
return ddev;
free_dev:
kfree(ddev);
return NULL;
}
EXPORT_SYMBOL(nfc_digital_allocate_device);
void nfc_digital_free_device(struct nfc_digital_dev *ddev)
{
nfc_free_device(ddev->nfc_dev);
kfree(ddev);
}
EXPORT_SYMBOL(nfc_digital_free_device);
int nfc_digital_register_device(struct nfc_digital_dev *ddev)
{
return nfc_register_device(ddev->nfc_dev);
}
EXPORT_SYMBOL(nfc_digital_register_device);
void nfc_digital_unregister_device(struct nfc_digital_dev *ddev)
{
struct digital_cmd *cmd, *n;
nfc_unregister_device(ddev->nfc_dev);
mutex_lock(&ddev->poll_lock);
ddev->poll_tech_count = 0;
mutex_unlock(&ddev->poll_lock);
cancel_work_sync(&ddev->poll_work);
cancel_work_sync(&ddev->cmd_work);
cancel_work_sync(&ddev->cmd_complete_work);
list_for_each_entry_safe(cmd, n, &ddev->cmd_queue, queue) {
list_del(&cmd->queue);
kfree(cmd);
}
}
EXPORT_SYMBOL(nfc_digital_unregister_device);
MODULE_LICENSE("GPL");