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linux/drivers/nfc/st95hf/core.c
Johannes Berg 634fef6107 networking: add and use skb_put_u8() 
Joe and Bjørn suggested that it'd be nicer to not have the
cast in the fairly common case of doing
	*(u8 *)skb_put(skb, 1) = c;

Add skb_put_u8() for this case, and use it across the code,
using the following spatch:

    @@
    expression SKB, C, S;
    typedef u8;
    identifier fn = {skb_put};
    fresh identifier fn2 = fn ## "_u8";
    @@
    - *(u8 *)fn(SKB, S) = C;
    + fn2(SKB, C);

Note that due to the "S", the spatch isn't perfect, it should
have checked that S is 1, but there's also places that use a
sizeof expression like sizeof(var) or sizeof(u8) etc. Turns
out that nobody ever did something like
	*(u8 *)skb_put(skb, 2) = c;

which would be wrong anyway since the second byte wouldn't be
initialized.

Suggested-by: Joe Perches <joe@perches.com>
Suggested-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2017-06-16 11:48:40 -04:00

1274 lines
33 KiB
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/*
* --------------------------------------------------------------------
* Driver for ST NFC Transceiver ST95HF
* --------------------------------------------------------------------
* Copyright (C) 2015 STMicroelectronics Pvt. Ltd. All rights reserved.
*
* 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 that 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <linux/err.h>
#include <linux/gpio.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/netdevice.h>
#include <linux/nfc.h>
#include <linux/of_gpio.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/property.h>
#include <linux/regulator/consumer.h>
#include <linux/wait.h>
#include <net/nfc/digital.h>
#include <net/nfc/nfc.h>
#include "spi.h"
/* supported protocols */
#define ST95HF_SUPPORTED_PROT (NFC_PROTO_ISO14443_MASK | \
NFC_PROTO_ISO14443_B_MASK | \
NFC_PROTO_ISO15693_MASK)
/* driver capabilities */
#define ST95HF_CAPABILITIES NFC_DIGITAL_DRV_CAPS_IN_CRC
/* Command Send Interface */
/* ST95HF_COMMAND_SEND CMD Ids */
#define ECHO_CMD 0x55
#define WRITE_REGISTER_CMD 0x9
#define PROTOCOL_SELECT_CMD 0x2
#define SEND_RECEIVE_CMD 0x4
/* Select protocol codes */
#define ISO15693_PROTOCOL_CODE 0x1
#define ISO14443A_PROTOCOL_CODE 0x2
#define ISO14443B_PROTOCOL_CODE 0x3
/*
* head room len is 3
* 1 byte for control byte
* 1 byte for cmd
* 1 byte for size
*/
#define ST95HF_HEADROOM_LEN 3
/*
* tailroom is 1 for ISO14443A
* and 0 for ISO14443B/ISO15693,
* hence the max value 1 should be
* taken.
*/
#define ST95HF_TAILROOM_LEN 1
/* Command Response interface */
#define MAX_RESPONSE_BUFFER_SIZE 280
#define ECHORESPONSE 0x55
#define ST95HF_ERR_MASK 0xF
#define ST95HF_TIMEOUT_ERROR 0x87
#define ST95HF_NFCA_CRC_ERR_MASK 0x20
#define ST95HF_NFCB_CRC_ERR_MASK 0x01
/* ST95HF transmission flag values */
#define TRFLAG_NFCA_SHORT_FRAME 0x07
#define TRFLAG_NFCA_STD_FRAME 0x08
#define TRFLAG_NFCA_STD_FRAME_CRC 0x28
/* Misc defs */
#define HIGH 1
#define LOW 0
#define ISO14443A_RATS_REQ 0xE0
#define RATS_TB1_PRESENT_MASK 0x20
#define RATS_TA1_PRESENT_MASK 0x10
#define TB1_FWI_MASK 0xF0
#define WTX_REQ_FROM_TAG 0xF2
#define MAX_CMD_LEN 0x7
#define MAX_CMD_PARAMS 4
struct cmd {
int cmd_len;
unsigned char cmd_id;
unsigned char no_cmd_params;
unsigned char cmd_params[MAX_CMD_PARAMS];
enum req_type req;
};
struct param_list {
int param_offset;
int new_param_val;
};
/*
* List of top-level cmds to be used internally by the driver.
* All these commands are build on top of ST95HF basic commands
* such as SEND_RECEIVE_CMD, PROTOCOL_SELECT_CMD, etc.
* These top level cmds are used internally while implementing various ops of
* digital layer/driver probe or extending the digital framework layer for
* features that are not yet implemented there, for example, WTX cmd handling.
*/
enum st95hf_cmd_list {
CMD_ECHO,
CMD_ISO14443A_CONFIG,
CMD_ISO14443A_DEMOGAIN,
CMD_ISO14443B_DEMOGAIN,
CMD_ISO14443A_PROTOCOL_SELECT,
CMD_ISO14443B_PROTOCOL_SELECT,
CMD_WTX_RESPONSE,
CMD_FIELD_OFF,
CMD_ISO15693_PROTOCOL_SELECT,
};
static const struct cmd cmd_array[] = {
[CMD_ECHO] = {
.cmd_len = 0x2,
.cmd_id = ECHO_CMD,
.no_cmd_params = 0,
.req = SYNC,
},
[CMD_ISO14443A_CONFIG] = {
.cmd_len = 0x7,
.cmd_id = WRITE_REGISTER_CMD,
.no_cmd_params = 0x4,
.cmd_params = {0x3A, 0x00, 0x5A, 0x04},
.req = SYNC,
},
[CMD_ISO14443A_DEMOGAIN] = {
.cmd_len = 0x7,
.cmd_id = WRITE_REGISTER_CMD,
.no_cmd_params = 0x4,
.cmd_params = {0x68, 0x01, 0x01, 0xDF},
.req = SYNC,
},
[CMD_ISO14443B_DEMOGAIN] = {
.cmd_len = 0x7,
.cmd_id = WRITE_REGISTER_CMD,
.no_cmd_params = 0x4,
.cmd_params = {0x68, 0x01, 0x01, 0x51},
.req = SYNC,
},
[CMD_ISO14443A_PROTOCOL_SELECT] = {
.cmd_len = 0x7,
.cmd_id = PROTOCOL_SELECT_CMD,
.no_cmd_params = 0x4,
.cmd_params = {ISO14443A_PROTOCOL_CODE, 0x00, 0x01, 0xA0},
.req = SYNC,
},
[CMD_ISO14443B_PROTOCOL_SELECT] = {
.cmd_len = 0x7,
.cmd_id = PROTOCOL_SELECT_CMD,
.no_cmd_params = 0x4,
.cmd_params = {ISO14443B_PROTOCOL_CODE, 0x01, 0x03, 0xFF},
.req = SYNC,
},
[CMD_WTX_RESPONSE] = {
.cmd_len = 0x6,
.cmd_id = SEND_RECEIVE_CMD,
.no_cmd_params = 0x3,
.cmd_params = {0xF2, 0x00, TRFLAG_NFCA_STD_FRAME_CRC},
.req = ASYNC,
},
[CMD_FIELD_OFF] = {
.cmd_len = 0x5,
.cmd_id = PROTOCOL_SELECT_CMD,
.no_cmd_params = 0x2,
.cmd_params = {0x0, 0x0},
.req = SYNC,
},
[CMD_ISO15693_PROTOCOL_SELECT] = {
.cmd_len = 0x5,
.cmd_id = PROTOCOL_SELECT_CMD,
.no_cmd_params = 0x2,
.cmd_params = {ISO15693_PROTOCOL_CODE, 0x0D},
.req = SYNC,
},
};
/* st95_digital_cmd_complete_arg stores client context */
struct st95_digital_cmd_complete_arg {
struct sk_buff *skb_resp;
nfc_digital_cmd_complete_t complete_cb;
void *cb_usrarg;
bool rats;
};
/*
* structure containing ST95HF driver specific data.
* @spicontext: structure containing information required
* for spi communication between st95hf and host.
* @ddev: nfc digital device object.
* @nfcdev: nfc device object.
* @enable_gpio: gpio used to enable st95hf transceiver.
* @complete_cb_arg: structure to store various context information
* that is passed from nfc requesting thread to the threaded ISR.
* @st95hf_supply: regulator "consumer" for NFC device.
* @sendrcv_trflag: last byte of frame send by sendrecv command
* of st95hf. This byte contains transmission flag info.
* @exchange_lock: semaphore used for signaling the st95hf_remove
* function that the last outstanding async nfc request is finished.
* @rm_lock: mutex for ensuring safe access of nfc digital object
* from threaded ISR. Usage of this mutex avoids any race between
* deletion of the object from st95hf_remove() and its access from
* the threaded ISR.
* @nfcdev_free: flag to have the state of nfc device object.
* [alive | died]
* @current_protocol: current nfc protocol.
* @current_rf_tech: current rf technology.
* @fwi: frame waiting index, received in reply of RATS according to
* digital protocol.
*/
struct st95hf_context {
struct st95hf_spi_context spicontext;
struct nfc_digital_dev *ddev;
struct nfc_dev *nfcdev;
unsigned int enable_gpio;
struct st95_digital_cmd_complete_arg complete_cb_arg;
struct regulator *st95hf_supply;
unsigned char sendrcv_trflag;
struct semaphore exchange_lock;
struct mutex rm_lock;
bool nfcdev_free;
u8 current_protocol;
u8 current_rf_tech;
int fwi;
};
/*
* st95hf_send_recv_cmd() is for sending commands to ST95HF
* that are described in the cmd_array[]. It can optionally
* receive the response if the cmd request is of type
* SYNC. For that to happen caller must pass true to recv_res.
* For ASYNC request, recv_res is ignored and the
* function will never try to receive the response on behalf
* of the caller.
*/
static int st95hf_send_recv_cmd(struct st95hf_context *st95context,
enum st95hf_cmd_list cmd,
int no_modif,
struct param_list *list_array,
bool recv_res)
{
unsigned char spi_cmd_buffer[MAX_CMD_LEN];
int i, ret;
struct device *dev = &st95context->spicontext.spidev->dev;
if (cmd_array[cmd].cmd_len > MAX_CMD_LEN)
return -EINVAL;
if (cmd_array[cmd].no_cmd_params < no_modif)
return -EINVAL;
if (no_modif && !list_array)
return -EINVAL;
spi_cmd_buffer[0] = ST95HF_COMMAND_SEND;
spi_cmd_buffer[1] = cmd_array[cmd].cmd_id;
spi_cmd_buffer[2] = cmd_array[cmd].no_cmd_params;
memcpy(&spi_cmd_buffer[3], cmd_array[cmd].cmd_params,
spi_cmd_buffer[2]);
for (i = 0; i < no_modif; i++) {
if (list_array[i].param_offset >= cmd_array[cmd].no_cmd_params)
return -EINVAL;
spi_cmd_buffer[3 + list_array[i].param_offset] =
list_array[i].new_param_val;
}
ret = st95hf_spi_send(&st95context->spicontext,
spi_cmd_buffer,
cmd_array[cmd].cmd_len,
cmd_array[cmd].req);
if (ret) {
dev_err(dev, "st95hf_spi_send failed with error %d\n", ret);
return ret;
}
if (cmd_array[cmd].req == SYNC && recv_res) {
unsigned char st95hf_response_arr[2];
ret = st95hf_spi_recv_response(&st95context->spicontext,
st95hf_response_arr);
if (ret < 0) {
dev_err(dev, "spi error from st95hf_spi_recv_response(), err = 0x%x\n",
ret);
return ret;
}
if (st95hf_response_arr[0]) {
dev_err(dev, "st95hf error from st95hf_spi_recv_response(), err = 0x%x\n",
st95hf_response_arr[0]);
return -EIO;
}
}
return 0;
}
static int st95hf_echo_command(struct st95hf_context *st95context)
{
int result = 0;
unsigned char echo_response;
result = st95hf_send_recv_cmd(st95context, CMD_ECHO, 0, NULL, false);
if (result)
return result;
/* If control reached here, response can be taken */
result = st95hf_spi_recv_echo_res(&st95context->spicontext,
&echo_response);
if (result) {
dev_err(&st95context->spicontext.spidev->dev,
"err: echo response receieve error = 0x%x\n", result);
return result;
}
if (echo_response == ECHORESPONSE)
return 0;
dev_err(&st95context->spicontext.spidev->dev, "err: echo res is 0x%x\n",
echo_response);
return -EIO;
}
static int secondary_configuration_type4a(struct st95hf_context *stcontext)
{
int result = 0;
struct device *dev = &stcontext->nfcdev->dev;
/* 14443A config setting after select protocol */
result = st95hf_send_recv_cmd(stcontext,
CMD_ISO14443A_CONFIG,
0,
NULL,
true);
if (result) {
dev_err(dev, "type a config cmd, err = 0x%x\n", result);
return result;
}
/* 14443A demo gain setting */
result = st95hf_send_recv_cmd(stcontext,
CMD_ISO14443A_DEMOGAIN,
0,
NULL,
true);
if (result)
dev_err(dev, "type a demogain cmd, err = 0x%x\n", result);
return result;
}
static int secondary_configuration_type4b(struct st95hf_context *stcontext)
{
int result = 0;
struct device *dev = &stcontext->nfcdev->dev;
result = st95hf_send_recv_cmd(stcontext,
CMD_ISO14443B_DEMOGAIN,
0,
NULL,
true);
if (result)
dev_err(dev, "type b demogain cmd, err = 0x%x\n", result);
return result;
}
static int st95hf_select_protocol(struct st95hf_context *stcontext, int type)
{
int result = 0;
struct device *dev;
dev = &stcontext->nfcdev->dev;
switch (type) {
case NFC_DIGITAL_RF_TECH_106A:
stcontext->current_rf_tech = NFC_DIGITAL_RF_TECH_106A;
result = st95hf_send_recv_cmd(stcontext,
CMD_ISO14443A_PROTOCOL_SELECT,
0,
NULL,
true);
if (result) {
dev_err(dev, "protocol sel, err = 0x%x\n",
result);
return result;
}
/* secondary config. for 14443Type 4A after protocol select */
result = secondary_configuration_type4a(stcontext);
if (result) {
dev_err(dev, "type a secondary config, err = 0x%x\n",
result);
return result;
}
break;
case NFC_DIGITAL_RF_TECH_106B:
stcontext->current_rf_tech = NFC_DIGITAL_RF_TECH_106B;
result = st95hf_send_recv_cmd(stcontext,
CMD_ISO14443B_PROTOCOL_SELECT,
0,
NULL,
true);
if (result) {
dev_err(dev, "protocol sel send, err = 0x%x\n",
result);
return result;
}
/*
* delay of 5-6 ms is required after select protocol
* command in case of ISO14443 Type B
*/
usleep_range(50000, 60000);
/* secondary config. for 14443Type 4B after protocol select */
result = secondary_configuration_type4b(stcontext);
if (result) {
dev_err(dev, "type b secondary config, err = 0x%x\n",
result);
return result;
}
break;
case NFC_DIGITAL_RF_TECH_ISO15693:
stcontext->current_rf_tech = NFC_DIGITAL_RF_TECH_ISO15693;
result = st95hf_send_recv_cmd(stcontext,
CMD_ISO15693_PROTOCOL_SELECT,
0,
NULL,
true);
if (result) {
dev_err(dev, "protocol sel send, err = 0x%x\n",
result);
return result;
}
break;
default:
return -EINVAL;
}
return 0;
}
static void st95hf_send_st95enable_negativepulse(struct st95hf_context *st95con)
{
/* First make irq_in pin high */
gpio_set_value(st95con->enable_gpio, HIGH);
/* wait for 1 milisecond */
usleep_range(1000, 2000);
/* Make irq_in pin low */
gpio_set_value(st95con->enable_gpio, LOW);
/* wait for minimum interrupt pulse to make st95 active */
usleep_range(1000, 2000);
/* At end make it high */
gpio_set_value(st95con->enable_gpio, HIGH);
}
/*
* Send a reset sequence over SPI bus (Reset command + wait 3ms +
* negative pulse on st95hf enable gpio
*/
static int st95hf_send_spi_reset_sequence(struct st95hf_context *st95context)
{
int result = 0;
unsigned char reset_cmd = ST95HF_COMMAND_RESET;
result = st95hf_spi_send(&st95context->spicontext,
&reset_cmd,
ST95HF_RESET_CMD_LEN,
ASYNC);
if (result) {
dev_err(&st95context->spicontext.spidev->dev,
"spi reset sequence cmd error = %d", result);
return result;
}
/* wait for 3 milisecond to complete the controller reset process */
usleep_range(3000, 4000);
/* send negative pulse to make st95hf active */
st95hf_send_st95enable_negativepulse(st95context);
/* wait for 10 milisecond : HFO setup time */
usleep_range(10000, 20000);
return result;
}
static int st95hf_por_sequence(struct st95hf_context *st95context)
{
int nth_attempt = 1;
int result;
st95hf_send_st95enable_negativepulse(st95context);
usleep_range(5000, 6000);
do {
/* send an ECHO command and checks ST95HF response */
result = st95hf_echo_command(st95context);
dev_dbg(&st95context->spicontext.spidev->dev,
"response from echo function = 0x%x, attempt = %d\n",
result, nth_attempt);
if (!result)
return 0;
/* send an pulse on IRQ in case of the chip is on sleep state */
if (nth_attempt == 2)
st95hf_send_st95enable_negativepulse(st95context);
else
st95hf_send_spi_reset_sequence(st95context);
/* delay of 50 milisecond */
usleep_range(50000, 51000);
} while (nth_attempt++ < 3);
return -ETIMEDOUT;
}
static int iso14443_config_fdt(struct st95hf_context *st95context, int wtxm)
{
int result = 0;
struct device *dev = &st95context->spicontext.spidev->dev;
struct nfc_digital_dev *nfcddev = st95context->ddev;
unsigned char pp_typeb;
struct param_list new_params[2];
pp_typeb = cmd_array[CMD_ISO14443B_PROTOCOL_SELECT].cmd_params[2];
if (nfcddev->curr_protocol == NFC_PROTO_ISO14443 &&
st95context->fwi < 4)
st95context->fwi = 4;
new_params[0].param_offset = 2;
if (nfcddev->curr_protocol == NFC_PROTO_ISO14443)
new_params[0].new_param_val = st95context->fwi;
else if (nfcddev->curr_protocol == NFC_PROTO_ISO14443_B)
new_params[0].new_param_val = pp_typeb;
new_params[1].param_offset = 3;
new_params[1].new_param_val = wtxm;
switch (nfcddev->curr_protocol) {
case NFC_PROTO_ISO14443:
result = st95hf_send_recv_cmd(st95context,
CMD_ISO14443A_PROTOCOL_SELECT,
2,
new_params,
true);
if (result) {
dev_err(dev, "WTX type a sel proto, err = 0x%x\n",
result);
return result;
}
/* secondary config. for 14443Type 4A after protocol select */
result = secondary_configuration_type4a(st95context);
if (result) {
dev_err(dev, "WTX type a second. config, err = 0x%x\n",
result);
return result;
}
break;
case NFC_PROTO_ISO14443_B:
result = st95hf_send_recv_cmd(st95context,
CMD_ISO14443B_PROTOCOL_SELECT,
2,
new_params,
true);
if (result) {
dev_err(dev, "WTX type b sel proto, err = 0x%x\n",
result);
return result;
}
/* secondary config. for 14443Type 4B after protocol select */
result = secondary_configuration_type4b(st95context);
if (result) {
dev_err(dev, "WTX type b second. config, err = 0x%x\n",
result);
return result;
}
break;
default:
return -EINVAL;
}
return 0;
}
static int st95hf_handle_wtx(struct st95hf_context *stcontext,
bool new_wtx,
int wtx_val)
{
int result = 0;
unsigned char val_mm = 0;
struct param_list new_params[1];
struct nfc_digital_dev *nfcddev = stcontext->ddev;
struct device *dev = &stcontext->nfcdev->dev;
if (new_wtx) {
result = iso14443_config_fdt(stcontext, wtx_val & 0x3f);
if (result) {
dev_err(dev, "Config. setting error on WTX req, err = 0x%x\n",
result);
return result;
}
/* Send response of wtx with ASYNC as no response expected */
new_params[0].param_offset = 1;
new_params[0].new_param_val = wtx_val;
result = st95hf_send_recv_cmd(stcontext,
CMD_WTX_RESPONSE,
1,
new_params,
false);
if (result)
dev_err(dev, "WTX response send, err = 0x%x\n", result);
return result;
}
/* if no new wtx, cofigure with default values */
if (nfcddev->curr_protocol == NFC_PROTO_ISO14443)
val_mm = cmd_array[CMD_ISO14443A_PROTOCOL_SELECT].cmd_params[3];
else if (nfcddev->curr_protocol == NFC_PROTO_ISO14443_B)
val_mm = cmd_array[CMD_ISO14443B_PROTOCOL_SELECT].cmd_params[3];
result = iso14443_config_fdt(stcontext, val_mm);
if (result)
dev_err(dev, "Default config. setting error after WTX processing, err = 0x%x\n",
result);
return result;
}
static int st95hf_error_handling(struct st95hf_context *stcontext,
struct sk_buff *skb_resp,
int res_len)
{
int result = 0;
unsigned char error_byte;
struct device *dev = &stcontext->nfcdev->dev;
/* First check ST95HF specific error */
if (skb_resp->data[0] & ST95HF_ERR_MASK) {
if (skb_resp->data[0] == ST95HF_TIMEOUT_ERROR)
result = -ETIMEDOUT;
else
result = -EIO;
return result;
}
/* Check for CRC err only if CRC is present in the tag response */
switch (stcontext->current_rf_tech) {
case NFC_DIGITAL_RF_TECH_106A:
if (stcontext->sendrcv_trflag == TRFLAG_NFCA_STD_FRAME_CRC) {
error_byte = skb_resp->data[res_len - 3];
if (error_byte & ST95HF_NFCA_CRC_ERR_MASK) {
/* CRC error occurred */
dev_err(dev, "CRC error, byte received = 0x%x\n",
error_byte);
result = -EIO;
}
}
break;
case NFC_DIGITAL_RF_TECH_106B:
case NFC_DIGITAL_RF_TECH_ISO15693:
error_byte = skb_resp->data[res_len - 1];
if (error_byte & ST95HF_NFCB_CRC_ERR_MASK) {
/* CRC error occurred */
dev_err(dev, "CRC error, byte received = 0x%x\n",
error_byte);
result = -EIO;
}
break;
}
return result;
}
static int st95hf_response_handler(struct st95hf_context *stcontext,
struct sk_buff *skb_resp,
int res_len)
{
int result = 0;
int skb_len;
unsigned char val_mm;
struct nfc_digital_dev *nfcddev = stcontext->ddev;
struct device *dev = &stcontext->nfcdev->dev;
struct st95_digital_cmd_complete_arg *cb_arg;
cb_arg = &stcontext->complete_cb_arg;
/* Process the response */
skb_put(skb_resp, res_len);
/* Remove st95 header */
skb_pull(skb_resp, 2);
skb_len = skb_resp->len;
/* check if it is case of RATS request reply & FWI is present */
if (nfcddev->curr_protocol == NFC_PROTO_ISO14443 && cb_arg->rats &&
(skb_resp->data[1] & RATS_TB1_PRESENT_MASK)) {
if (skb_resp->data[1] & RATS_TA1_PRESENT_MASK)
stcontext->fwi =
(skb_resp->data[3] & TB1_FWI_MASK) >> 4;
else
stcontext->fwi =
(skb_resp->data[2] & TB1_FWI_MASK) >> 4;
val_mm = cmd_array[CMD_ISO14443A_PROTOCOL_SELECT].cmd_params[3];
result = iso14443_config_fdt(stcontext, val_mm);
if (result) {
dev_err(dev, "error in config_fdt to handle fwi of ATS, error=%d\n",
result);
return result;
}
}
cb_arg->rats = false;
/* Remove CRC bytes only if received frames data has an eod (CRC) */
switch (stcontext->current_rf_tech) {
case NFC_DIGITAL_RF_TECH_106A:
if (stcontext->sendrcv_trflag == TRFLAG_NFCA_STD_FRAME_CRC)
skb_trim(skb_resp, (skb_len - 5));
else
skb_trim(skb_resp, (skb_len - 3));
break;
case NFC_DIGITAL_RF_TECH_106B:
case NFC_DIGITAL_RF_TECH_ISO15693:
skb_trim(skb_resp, (skb_len - 3));
break;
}
return result;
}
static irqreturn_t st95hf_irq_handler(int irq, void *st95hfcontext)
{
struct st95hf_context *stcontext =
(struct st95hf_context *)st95hfcontext;
if (stcontext->spicontext.req_issync) {
complete(&stcontext->spicontext.done);
stcontext->spicontext.req_issync = false;
return IRQ_HANDLED;
}
return IRQ_WAKE_THREAD;
}
static irqreturn_t st95hf_irq_thread_handler(int irq, void *st95hfcontext)
{
int result = 0;
int res_len;
static bool wtx;
struct device *dev;
struct device *spidevice;
struct nfc_digital_dev *nfcddev;
struct sk_buff *skb_resp;
struct st95hf_context *stcontext =
(struct st95hf_context *)st95hfcontext;
struct st95_digital_cmd_complete_arg *cb_arg;
spidevice = &stcontext->spicontext.spidev->dev;
/*
* check semaphore, if not down() already, then we don't
* know in which context the ISR is called and surely it
* will be a bug. Note that down() of the semaphore is done
* in the corresponding st95hf_in_send_cmd() and then
* only this ISR should be called. ISR will up() the
* semaphore before leaving. Hence when the ISR is called
* the correct behaviour is down_trylock() should always
* return 1 (indicating semaphore cant be taken and hence no
* change in semaphore count).
* If not, then we up() the semaphore and crash on
* a BUG() !
*/
if (!down_trylock(&stcontext->exchange_lock)) {
up(&stcontext->exchange_lock);
WARN(1, "unknown context in ST95HF ISR");
return IRQ_NONE;
}
cb_arg = &stcontext->complete_cb_arg;
skb_resp = cb_arg->skb_resp;
mutex_lock(&stcontext->rm_lock);
res_len = st95hf_spi_recv_response(&stcontext->spicontext,
skb_resp->data);
if (res_len < 0) {
dev_err(spidevice, "TISR spi response err = 0x%x\n", res_len);
result = res_len;
goto end;
}
/* if stcontext->nfcdev_free is true, it means remove already ran */
if (stcontext->nfcdev_free) {
result = -ENODEV;
goto end;
}
dev = &stcontext->nfcdev->dev;
nfcddev = stcontext->ddev;
if (skb_resp->data[2] == WTX_REQ_FROM_TAG) {
/* Request for new FWT from tag */
result = st95hf_handle_wtx(stcontext, true, skb_resp->data[3]);
if (result)
goto end;
wtx = true;
mutex_unlock(&stcontext->rm_lock);
return IRQ_HANDLED;
}
result = st95hf_error_handling(stcontext, skb_resp, res_len);
if (result)
goto end;
result = st95hf_response_handler(stcontext, skb_resp, res_len);
if (result)
goto end;
/*
* If select protocol is done on wtx req. do select protocol
* again with default values
*/
if (wtx) {
wtx = false;
result = st95hf_handle_wtx(stcontext, false, 0);
if (result)
goto end;
}
/* call digital layer callback */
cb_arg->complete_cb(stcontext->ddev, cb_arg->cb_usrarg, skb_resp);
/* up the semaphore before returning */
up(&stcontext->exchange_lock);
mutex_unlock(&stcontext->rm_lock);
return IRQ_HANDLED;
end:
kfree_skb(skb_resp);
wtx = false;
cb_arg->rats = false;
skb_resp = ERR_PTR(result);
/* call of callback with error */
cb_arg->complete_cb(stcontext->ddev, cb_arg->cb_usrarg, skb_resp);
/* up the semaphore before returning */
up(&stcontext->exchange_lock);
mutex_unlock(&stcontext->rm_lock);
return IRQ_HANDLED;
}
/* NFC ops functions definition */
static int st95hf_in_configure_hw(struct nfc_digital_dev *ddev,
int type,
int param)
{
struct st95hf_context *stcontext = nfc_digital_get_drvdata(ddev);
if (type == NFC_DIGITAL_CONFIG_RF_TECH)
return st95hf_select_protocol(stcontext, param);
if (type == NFC_DIGITAL_CONFIG_FRAMING) {
switch (param) {
case NFC_DIGITAL_FRAMING_NFCA_SHORT:
stcontext->sendrcv_trflag = TRFLAG_NFCA_SHORT_FRAME;
break;
case NFC_DIGITAL_FRAMING_NFCA_STANDARD:
stcontext->sendrcv_trflag = TRFLAG_NFCA_STD_FRAME;
break;
case NFC_DIGITAL_FRAMING_NFCA_T4T:
case NFC_DIGITAL_FRAMING_NFCA_NFC_DEP:
case NFC_DIGITAL_FRAMING_NFCA_STANDARD_WITH_CRC_A:
stcontext->sendrcv_trflag = TRFLAG_NFCA_STD_FRAME_CRC;
break;
case NFC_DIGITAL_FRAMING_NFCB:
case NFC_DIGITAL_FRAMING_ISO15693_INVENTORY:
case NFC_DIGITAL_FRAMING_ISO15693_T5T:
break;
}
}
return 0;
}
static int rf_off(struct st95hf_context *stcontext)
{
int rc;
struct device *dev;
dev = &stcontext->nfcdev->dev;
rc = st95hf_send_recv_cmd(stcontext, CMD_FIELD_OFF, 0, NULL, true);
if (rc)
dev_err(dev, "protocol sel send field off, err = 0x%x\n", rc);
return rc;
}
static int st95hf_in_send_cmd(struct nfc_digital_dev *ddev,
struct sk_buff *skb,
u16 timeout,
nfc_digital_cmd_complete_t cb,
void *arg)
{
struct st95hf_context *stcontext = nfc_digital_get_drvdata(ddev);
int rc;
struct sk_buff *skb_resp;
int len_data_to_tag = 0;
skb_resp = nfc_alloc_recv_skb(MAX_RESPONSE_BUFFER_SIZE, GFP_KERNEL);
if (!skb_resp) {
rc = -ENOMEM;
goto error;
}
switch (stcontext->current_rf_tech) {
case NFC_DIGITAL_RF_TECH_106A:
len_data_to_tag = skb->len + 1;
skb_put_u8(skb, stcontext->sendrcv_trflag);
break;
case NFC_DIGITAL_RF_TECH_106B:
case NFC_DIGITAL_RF_TECH_ISO15693:
len_data_to_tag = skb->len;
break;
default:
rc = -EINVAL;
goto free_skb_resp;
}
skb_push(skb, 3);
skb->data[0] = ST95HF_COMMAND_SEND;
skb->data[1] = SEND_RECEIVE_CMD;
skb->data[2] = len_data_to_tag;
stcontext->complete_cb_arg.skb_resp = skb_resp;
stcontext->complete_cb_arg.cb_usrarg = arg;
stcontext->complete_cb_arg.complete_cb = cb;
if ((skb->data[3] == ISO14443A_RATS_REQ) &&
ddev->curr_protocol == NFC_PROTO_ISO14443)
stcontext->complete_cb_arg.rats = true;
/*
* down the semaphore to indicate to remove func that an
* ISR is pending, note that it will not block here in any case.
* If found blocked, it is a BUG!
*/
rc = down_killable(&stcontext->exchange_lock);
if (rc) {
WARN(1, "Semaphore is not found up in st95hf_in_send_cmd\n");
return rc;
}
rc = st95hf_spi_send(&stcontext->spicontext, skb->data,
skb->len,
ASYNC);
if (rc) {
dev_err(&stcontext->nfcdev->dev,
"Error %d trying to perform data_exchange", rc);
/* up the semaphore since ISR will never come in this case */
up(&stcontext->exchange_lock);
goto free_skb_resp;
}
kfree_skb(skb);
return rc;
free_skb_resp:
kfree_skb(skb_resp);
error:
return rc;
}
/* p2p will be supported in a later release ! */
static int st95hf_tg_configure_hw(struct nfc_digital_dev *ddev,
int type,
int param)
{
return 0;
}
static int st95hf_tg_send_cmd(struct nfc_digital_dev *ddev,
struct sk_buff *skb,
u16 timeout,
nfc_digital_cmd_complete_t cb,
void *arg)
{
return 0;
}
static int st95hf_tg_listen(struct nfc_digital_dev *ddev,
u16 timeout,
nfc_digital_cmd_complete_t cb,
void *arg)
{
return 0;
}
static int st95hf_tg_get_rf_tech(struct nfc_digital_dev *ddev, u8 *rf_tech)
{
return 0;
}
static int st95hf_switch_rf(struct nfc_digital_dev *ddev, bool on)
{
u8 rf_tech;
struct st95hf_context *stcontext = nfc_digital_get_drvdata(ddev);
rf_tech = ddev->curr_rf_tech;
if (on)
/* switch on RF field */
return st95hf_select_protocol(stcontext, rf_tech);
/* switch OFF RF field */
return rf_off(stcontext);
}
/* TODO st95hf_abort_cmd */
static void st95hf_abort_cmd(struct nfc_digital_dev *ddev)
{
}
static struct nfc_digital_ops st95hf_nfc_digital_ops = {
.in_configure_hw = st95hf_in_configure_hw,
.in_send_cmd = st95hf_in_send_cmd,
.tg_listen = st95hf_tg_listen,
.tg_configure_hw = st95hf_tg_configure_hw,
.tg_send_cmd = st95hf_tg_send_cmd,
.tg_get_rf_tech = st95hf_tg_get_rf_tech,
.switch_rf = st95hf_switch_rf,
.abort_cmd = st95hf_abort_cmd,
};
static const struct spi_device_id st95hf_id[] = {
{ "st95hf", 0 },
{}
};
MODULE_DEVICE_TABLE(spi, st95hf_id);
static int st95hf_probe(struct spi_device *nfc_spi_dev)
{
int ret;
struct st95hf_context *st95context;
struct st95hf_spi_context *spicontext;
nfc_info(&nfc_spi_dev->dev, "ST95HF driver probe called.\n");
st95context = devm_kzalloc(&nfc_spi_dev->dev,
sizeof(struct st95hf_context),
GFP_KERNEL);
if (!st95context)
return -ENOMEM;
spicontext = &st95context->spicontext;
spicontext->spidev = nfc_spi_dev;
st95context->fwi =
cmd_array[CMD_ISO14443A_PROTOCOL_SELECT].cmd_params[2];
if (device_property_present(&nfc_spi_dev->dev, "st95hfvin")) {
st95context->st95hf_supply =
devm_regulator_get(&nfc_spi_dev->dev,
"st95hfvin");
if (IS_ERR(st95context->st95hf_supply)) {
dev_err(&nfc_spi_dev->dev, "failed to acquire regulator\n");
return PTR_ERR(st95context->st95hf_supply);
}
ret = regulator_enable(st95context->st95hf_supply);
if (ret) {
dev_err(&nfc_spi_dev->dev, "failed to enable regulator\n");
return ret;
}
}
init_completion(&spicontext->done);
mutex_init(&spicontext->spi_lock);
/*
* Store spicontext in spi device object for using it in
* remove function
*/
dev_set_drvdata(&nfc_spi_dev->dev, spicontext);
st95context->enable_gpio =
of_get_named_gpio(nfc_spi_dev->dev.of_node,
"enable-gpio",
0);
if (!gpio_is_valid(st95context->enable_gpio)) {
dev_err(&nfc_spi_dev->dev, "No valid enable gpio\n");
ret = st95context->enable_gpio;
goto err_disable_regulator;
}
ret = devm_gpio_request_one(&nfc_spi_dev->dev, st95context->enable_gpio,
GPIOF_DIR_OUT | GPIOF_INIT_HIGH,
"enable_gpio");
if (ret)
goto err_disable_regulator;
if (nfc_spi_dev->irq > 0) {
if (devm_request_threaded_irq(&nfc_spi_dev->dev,
nfc_spi_dev->irq,
st95hf_irq_handler,
st95hf_irq_thread_handler,
IRQF_TRIGGER_FALLING,
"st95hf",
(void *)st95context) < 0) {
dev_err(&nfc_spi_dev->dev, "err: irq request for st95hf is failed\n");
ret = -EINVAL;
goto err_disable_regulator;
}
} else {
dev_err(&nfc_spi_dev->dev, "not a valid IRQ associated with ST95HF\n");
ret = -EINVAL;
goto err_disable_regulator;
}
/*
* First reset SPI to handle warm reset of the system.
* It will put the ST95HF device in Power ON state
* which make the state of device identical to state
* at the time of cold reset of the system.
*/
ret = st95hf_send_spi_reset_sequence(st95context);
if (ret) {
dev_err(&nfc_spi_dev->dev, "err: spi_reset_sequence failed\n");
goto err_disable_regulator;
}
/* call PowerOnReset sequence of ST95hf to activate it */
ret = st95hf_por_sequence(st95context);
if (ret) {
dev_err(&nfc_spi_dev->dev, "err: por seq failed for st95hf\n");
goto err_disable_regulator;
}
/* create NFC dev object and register with NFC Subsystem */
st95context->ddev = nfc_digital_allocate_device(&st95hf_nfc_digital_ops,
ST95HF_SUPPORTED_PROT,
ST95HF_CAPABILITIES,
ST95HF_HEADROOM_LEN,
ST95HF_TAILROOM_LEN);
if (!st95context->ddev) {
ret = -ENOMEM;
goto err_disable_regulator;
}
st95context->nfcdev = st95context->ddev->nfc_dev;
nfc_digital_set_parent_dev(st95context->ddev, &nfc_spi_dev->dev);
ret = nfc_digital_register_device(st95context->ddev);
if (ret) {
dev_err(&st95context->nfcdev->dev, "st95hf registration failed\n");
goto err_free_digital_device;
}
/* store st95context in nfc device object */
nfc_digital_set_drvdata(st95context->ddev, st95context);
sema_init(&st95context->exchange_lock, 1);
mutex_init(&st95context->rm_lock);
return ret;
err_free_digital_device:
nfc_digital_free_device(st95context->ddev);
err_disable_regulator:
if (st95context->st95hf_supply)
regulator_disable(st95context->st95hf_supply);
return ret;
}
static int st95hf_remove(struct spi_device *nfc_spi_dev)
{
int result = 0;
unsigned char reset_cmd = ST95HF_COMMAND_RESET;
struct st95hf_spi_context *spictx = dev_get_drvdata(&nfc_spi_dev->dev);
struct st95hf_context *stcontext = container_of(spictx,
struct st95hf_context,
spicontext);
mutex_lock(&stcontext->rm_lock);
nfc_digital_unregister_device(stcontext->ddev);
nfc_digital_free_device(stcontext->ddev);
stcontext->nfcdev_free = true;
mutex_unlock(&stcontext->rm_lock);
/* if last in_send_cmd's ISR is pending, wait for it to finish */
result = down_killable(&stcontext->exchange_lock);
if (result == -EINTR)
dev_err(&spictx->spidev->dev, "sleep for semaphore interrupted by signal\n");
/* next reset the ST95HF controller */
result = st95hf_spi_send(&stcontext->spicontext,
&reset_cmd,
ST95HF_RESET_CMD_LEN,
ASYNC);
if (result) {
dev_err(&spictx->spidev->dev,
"ST95HF reset failed in remove() err = %d\n", result);
return result;
}
/* wait for 3 ms to complete the controller reset process */
usleep_range(3000, 4000);
/* disable regulator */
if (stcontext->st95hf_supply)
regulator_disable(stcontext->st95hf_supply);
return result;
}
/* Register as SPI protocol driver */
static struct spi_driver st95hf_driver = {
.driver = {
.name = "st95hf",
.owner = THIS_MODULE,
},
.id_table = st95hf_id,
.probe = st95hf_probe,
.remove = st95hf_remove,
};
module_spi_driver(st95hf_driver);
MODULE_AUTHOR("Shikha Singh <shikha.singh@st.com>");
MODULE_DESCRIPTION("ST NFC Transceiver ST95HF driver");
MODULE_LICENSE("GPL v2");
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