cregit-Linux how code gets into the kernel

Release 4.8 net/nfc/digital_core.c

Directory: net/nfc
/*
 * 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.
 *
 */


#define pr_fmt(fmt) "digital: %s: " fmt, __func__

#include <linux/module.h>

#include "digital.h"


#define DIGITAL_PROTO_NFCA_RF_TECH \
	(NFC_PROTO_JEWEL_MASK | NFC_PROTO_MIFARE_MASK | \
        NFC_PROTO_NFC_DEP_MASK | NFC_PROTO_ISO14443_MASK)


#define DIGITAL_PROTO_NFCB_RF_TECH	NFC_PROTO_ISO14443_B_MASK


#define DIGITAL_PROTO_NFCF_RF_TECH \
	(NFC_PROTO_FELICA_MASK | NFC_PROTO_NFC_DEP_MASK)


#define DIGITAL_PROTO_ISO15693_RF_TECH	NFC_PROTO_ISO15693_MASK

/* Delay between each poll frame (ms) */

#define DIGITAL_POLL_INTERVAL 10


struct digital_cmd {
	
struct list_head queue;

	
u8 type;
	
u8 pending;

	
u16 timeout;
	
struct sk_buff *req;
	
struct sk_buff *resp;
	
struct digital_tg_mdaa_params *mdaa_params;

	
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; }

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void digital_skb_add_crc(struct sk_buff *skb, crc_func_t crc_func, u16 init, u8 bitwise_inv, u8 msb_first) { u16 crc; crc = crc_func(init, skb->data, skb->len); if (bitwise_inv) crc = ~crc; if (msb_first) crc = __fswab16(crc); *skb_put(skb, 1) = crc & 0xFF; *skb_put(skb, 1) = (crc >> 8) & 0xFF; }

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int digital_skb_check_crc(struct sk_buff *skb, crc_func_t crc_func, u16 crc_init, u8 bitwise_inv, u8 msb_first) { int rc; u16 crc; if (skb->len <= 2) return -EIO; crc = crc_func(crc_init, skb->data, skb->len - 2); if (bitwise_inv) crc = ~crc; if (msb_first) crc = __swab16(crc); rc = (skb->data[skb->len - 2] - (crc & 0xFF)) + (skb->data[skb->len - 1] - ((crc >> 8) & 0xFF)); if (rc) return -EIO; skb_trim(skb, skb->len - 2); return 0; }

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static inline void digital_switch_rf(struct nfc_digital_dev *ddev, bool on) { ddev->ops->switch_rf(ddev, on); }

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static inline void digital_abort_cmd(struct nfc_digital_dev *ddev) { ddev->ops->abort_cmd(ddev); }

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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->mdaa_params); kfree(cmd); schedule_work(&ddev->cmd_work); }

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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); }

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static void digital_wq_cmd(struct work_struct *work) { int rc; struct digital_cmd *cmd; struct digital_tg_mdaa_params *params; 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; } cmd->pending = 1; 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; case DIGITAL_CMD_TG_SEND: rc = ddev->ops->tg_send_cmd(ddev, cmd->req, cmd->timeout, digital_send_cmd_complete, cmd); break; case DIGITAL_CMD_TG_LISTEN: rc = ddev->ops->tg_listen(ddev, cmd->timeout, digital_send_cmd_complete, cmd); break; case DIGITAL_CMD_TG_LISTEN_MDAA: params = cmd->mdaa_params; rc = ddev->ops->tg_listen_mdaa(ddev, params, cmd->timeout, digital_send_cmd_complete, cmd); break; case DIGITAL_CMD_TG_LISTEN_MD: rc = ddev->ops->tg_listen_md(ddev, cmd->timeout, digital_send_cmd_complete, cmd); break; default: pr_err("Unknown cmd type %d\n", cmd->type); return; } if (!rc) return; pr_err("in_send_command returned err %d\n", rc); mutex_lock(&ddev->cmd_lock); list_del(&cmd->queue); mutex_unlock(&ddev->cmd_lock); kfree_skb(cmd->req); kfree(cmd->mdaa_params); kfree(cmd); schedule_work(&ddev->cmd_work); }

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int digital_send_cmd(struct nfc_digital_dev *ddev, u8 cmd_type, struct sk_buff *skb, struct digital_tg_mdaa_params *params, 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->mdaa_params = params; 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; }

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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\n", rc); return rc; }

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int digital_tg_configure_hw(struct nfc_digital_dev *ddev, int type, int param) { int rc; rc = ddev->ops->tg_configure_hw(ddev, type, param); if (rc) pr_err("tg_configure_hw failed: %d\n", rc); return rc; }

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static int digital_tg_listen_mdaa(struct nfc_digital_dev *ddev, u8 rf_tech) { struct digital_tg_mdaa_params *params; params = kzalloc(sizeof(struct digital_tg_mdaa_params), GFP_KERNEL); if (!params) return -ENOMEM; params->sens_res = DIGITAL_SENS_RES_NFC_DEP; get_random_bytes(params->nfcid1, sizeof(params->nfcid1)); params->sel_res = DIGITAL_SEL_RES_NFC_DEP; params->nfcid2[0] = DIGITAL_SENSF_NFCID2_NFC_DEP_B1; params->nfcid2[1] = DIGITAL_SENSF_NFCID2_NFC_DEP_B2; get_random_bytes(params->nfcid2 + 2, NFC_NFCID2_MAXSIZE - 2); params->sc = DIGITAL_SENSF_FELICA_SC; return digital_send_cmd(ddev, DIGITAL_CMD_TG_LISTEN_MDAA, NULL, params, 500, digital_tg_recv_atr_req, NULL); }

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static int digital_tg_listen_md(struct nfc_digital_dev *ddev, u8 rf_tech) { return digital_send_cmd(ddev, DIGITAL_CMD_TG_LISTEN_MD, NULL, NULL, 500, digital_tg_recv_md_req, NULL); }

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int digital_target_found(struct nfc_digital_dev *ddev, struct nfc_target *target, u8 protocol) { int rc; u8 framing; u8 rf_tech; u8 poll_tech_count; int (*check_crc)(struct sk_buff *skb); void (*add_crc)(struct sk_buff *skb); rf_tech = ddev->poll_techs[ddev->poll_tech_index].rf_tech; switch (protocol) { case NFC_PROTO_JEWEL: framing = NFC_DIGITAL_FRAMING_NFCA_T1T; check_crc = digital_skb_check_crc_b; add_crc = digital_skb_add_crc_b; break; case NFC_PROTO_MIFARE: framing = NFC_DIGITAL_FRAMING_NFCA_T2T; check_crc = digital_skb_check_crc_a; add_crc = digital_skb_add_crc_a; break; case NFC_PROTO_FELICA: framing = NFC_DIGITAL_FRAMING_NFCF_T3T; check_crc = digital_skb_check_crc_f; add_crc = digital_skb_add_crc_f; break; case NFC_PROTO_NFC_DEP: if (rf_tech == NFC_DIGITAL_RF_TECH_106A) { framing = NFC_DIGITAL_FRAMING_NFCA_NFC_DEP; check_crc = digital_skb_check_crc_a; add_crc = digital_skb_add_crc_a; } else { framing = NFC_DIGITAL_FRAMING_NFCF_NFC_DEP; check_crc = digital_skb_check_crc_f; add_crc = digital_skb_add_crc_f; } break; case NFC_PROTO_ISO15693: framing = NFC_DIGITAL_FRAMING_ISO15693_T5T; check_crc = digital_skb_check_crc_b; add_crc = digital_skb_add_crc_b; break; case NFC_PROTO_ISO14443: framing = NFC_DIGITAL_FRAMING_NFCA_T4T; check_crc = digital_skb_check_crc_a; add_crc = digital_skb_add_crc_a; break; case NFC_PROTO_ISO14443_B: framing = NFC_DIGITAL_FRAMING_NFCB_T4T; check_crc = digital_skb_check_crc_b; add_crc = digital_skb_add_crc_b; break; default: pr_err("Invalid protocol %d\n", protocol); return -EINVAL; } pr_debug("rf_tech=%d, protocol=%d\n", rf_tech, protocol); ddev->curr_rf_tech = rf_tech; if (DIGITAL_DRV_CAPS_IN_CRC(ddev)) { ddev->skb_add_crc = digital_skb_add_crc_none; ddev->skb_check_crc = digital_skb_check_crc_none; } else { ddev->skb_add_crc = add_crc; ddev->skb_check_crc = check_crc; } rc = digital_in_configure_hw(ddev, NFC_DIGITAL_CONFIG_FRAMING, framing); if (rc) return rc; target->supported_protocols = (1 << protocol); poll_tech_count = ddev->poll_tech_count; ddev->poll_tech_count = 0; rc = nfc_targets_found(ddev->nfc_dev, target, 1); if (rc) { ddev->poll_tech_count = poll_tech_count; return rc; } return 0; }

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void digital_poll_next_tech(struct nfc_digital_dev *ddev) { u8 rand_mod; digital_switch_rf(ddev, 0); mutex_lock(&ddev->poll_lock); if (!ddev->poll_tech_count) { mutex_unlock(&ddev->poll_lock); return; } get_random_bytes(&rand_mod, sizeof(rand_mod)); ddev->poll_tech_index = rand_mod % ddev->poll_tech_count; mutex_unlock(&ddev->poll_lock); schedule_delayed_work(&ddev->poll_work, msecs_to_jiffies(DIGITAL_POLL_INTERVAL)); }

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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.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); }

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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; }

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/** * 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_debug("protocols: im 0x%x, tm 0x%x, supported 0x%x\n", 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("Unknown protocol\n"); return -EINVAL; } if (ddev->poll_tech_count) { pr_err("Already polling\n"); return -EBUSY; } if (ddev->curr_protocol) { pr_err("A target is already active\n"); 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 (matching_im_protocols & DIGITAL_PROTO_NFCB_RF_TECH) digital_add_poll_tech(ddev, NFC_DIGITAL_RF_TECH_106B, digital_in_send_sensb_req); if (matching_im_protocols & DIGITAL_PROTO_NFCF_RF_TECH) { digital_add_poll_tech(ddev, NFC_DIGITAL_RF_TECH_212F, digital_in_send_sensf_req); digital_add_poll_tech(ddev, NFC_DIGITAL_RF_TECH_424F, digital_in_send_sensf_req); } if (matching_im_protocols & DIGITAL_PROTO_ISO15693_RF_TECH) digital_add_poll_tech(ddev, NFC_DIGITAL_RF_TECH_ISO15693, digital_in_send_iso15693_inv_req); if (matching_tm_protocols & NFC_PROTO_NFC_DEP_MASK) { if (ddev->ops->tg_listen_mdaa) { digital_add_poll_tech(ddev, 0, digital_tg_listen_mdaa); } else if (ddev->ops->tg_listen_md) { digital_add_poll_tech(ddev, 0, digital_tg_listen_md); } else { digital_add_poll_tech(ddev, NFC_DIGITAL_RF_TECH_106A, digital_tg_listen_nfca); digital_add_poll_tech(ddev, NFC_DIGITAL_RF_TECH_212F, digital_tg_listen_nfcf); digital_add_poll_tech(ddev, NFC_DIGITAL_RF_TECH_424F, digital_tg_listen_nfcf); } } if (!ddev->poll_tech_count) { pr_err("Unsupported protocols: im=0x%x, tm=0x%x\n", matching_im_protocols, matching_tm_protocols); return -EINVAL; } schedule_delayed_work(&ddev->poll_work, 0); return 0; }

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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\n"); mutex_unlock(&ddev->poll_lock); return; } ddev->poll_tech_count = 0; mutex_unlock(&ddev->poll_lock); cancel_delayed_work_sync(&ddev->poll_work); digital_abort_cmd(ddev); }

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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; }

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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; }

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static int digital_dep_link_up(struct nfc_dev *nfc_dev, struct nfc_target *target, __u8 comm_mode, __u8 *gb, size_t gb_len) { struct nfc_digital_dev *ddev = nfc_get_drvdata(nfc_dev); int rc; rc = digital_in_send_atr_req(ddev, target, comm_mode, gb, gb_len); if (!rc) ddev->curr_protocol = NFC_PROTO_NFC_DEP; return rc; }

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static int digital_dep_link_down(struct nfc_dev *nfc_dev) { struct nfc_digital_dev *ddev = nfc_get_drvdata(nfc_dev); digital_abort_cmd(ddev); ddev->curr_protocol = 0; return 0; }

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static int digital_activate_target(struct nfc_dev *nfc_dev, struct nfc_target *target, __u32 protocol) { struct nfc_digital_dev *ddev = nfc_get_drvdata(nfc_dev); if (ddev->poll_tech_count) { pr_err("Can't activate a target while polling\n"); return -EBUSY; } if (ddev->curr_protocol) { pr_err("A target is already active\n"); return -EBUSY; } ddev->curr_protocol = protocol; return 0; }

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static void digital_deactivate_target(struct nfc_dev *nfc_dev, struct nfc_target *target, u8 mode) { struct nfc_digital_dev *ddev = nfc_get_drvdata(nfc_dev); if (!ddev->curr_protocol) { pr_err("No active target\n"); return; } ddev->curr_protocol = 0; }

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static int digital_tg_send(struct nfc_dev *dev, struct sk_buff *skb) { struct nfc_digital_dev *ddev = nfc_get_drvdata(dev); return digital_tg_send_dep_res(ddev, skb); }

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static void digital_in_send_complete(struct nfc_digital_dev *ddev, void *arg, struct sk_buff *resp) { struct digital_data_exch *data_exch = arg; int rc; if (IS_ERR(resp)) { rc = PTR_ERR(resp); resp = NULL; goto done; } if (ddev->curr_protocol == NFC_PROTO_MIFARE) { rc = digital_in_recv_mifare_res(resp); /* crc check is done in digital_in_recv_mifare_res() */ goto done; } if ((ddev->curr_protocol == NFC_PROTO_ISO14443) || (ddev->curr_protocol == NFC_PROTO_ISO14443_B)) { rc = digital_in_iso_dep_pull_sod(ddev, resp); if (rc) goto done; } rc = ddev->skb_check_crc(resp); done: if (rc) { kfree_skb(resp); resp = NULL; } data_exch->cb(data_exch->cb_context, resp, rc); kfree(data_exch); }

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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) { struct nfc_digital_dev *ddev = nfc_get_drvdata(nfc_dev); struct digital_data_exch *data_exch; int rc; data_exch = kzalloc(sizeof(struct digital_data_exch), GFP_KERNEL); if (!data_exch) { pr_err("Failed to allocate data_exch struct\n"); return -ENOMEM; } data_exch->cb = cb; data_exch->cb_context = cb_context; if (ddev->curr_protocol == NFC_PROTO_NFC_DEP) { rc = digital_in_send_dep_req(