From f3e8fb552789f4845e60b11c47b676d14b9488e5 Mon Sep 17 00:00:00 2001 From: Eric Lapuyade Date: Tue, 11 Sep 2012 10:43:50 +0200 Subject: [PATCH] NFC: Modified hci_transceive to become an asynchronous operation This enables the completion callback to be called from a different context, preventing a possible deadlock if the callback resulted in the invocation of a nested call to the currently locked nfc_dev. This is also more in line with the im_transceive nfc_ops for NFC Core or NCI drivers which already behave asynchronously. Signed-off-by: Eric Lapuyade Signed-off-by: Samuel Ortiz --- drivers/nfc/pn544_hci.c | 57 ++++++++++++++++++++++++++++++----------- include/net/nfc/hci.h | 8 ++++-- include/net/nfc/shdlc.h | 4 +-- net/nfc/hci/core.c | 57 ++++++++++++++++++++++++++++------------- net/nfc/hci/shdlc.c | 5 ++-- 5 files changed, 92 insertions(+), 39 deletions(-) diff --git a/drivers/nfc/pn544_hci.c b/drivers/nfc/pn544_hci.c index d90aecfce739..a176d1f7bbf3 100644 --- a/drivers/nfc/pn544_hci.c +++ b/drivers/nfc/pn544_hci.c @@ -148,6 +148,9 @@ struct pn544_hci_info { * < 0 if hardware error occured (e.g. i2c err) * and prevents normal operation. */ + int async_cb_type; + data_exchange_cb_t async_cb; + void *async_cb_context; }; static void pn544_hci_platform_init(struct pn544_hci_info *info) @@ -731,6 +734,26 @@ static int pn544_hci_complete_target_discovered(struct nfc_shdlc *shdlc, return r; } +#define PN544_CB_TYPE_READER_F 1 + +static void pn544_hci_data_exchange_cb(void *context, struct sk_buff *skb, + int err) +{ + struct pn544_hci_info *info = context; + + switch (info->async_cb_type) { + case PN544_CB_TYPE_READER_F: + if (err == 0) + skb_pull(skb, 1); + info->async_cb(info->async_cb_context, skb, err); + break; + default: + if (err == 0) + kfree_skb(skb); + break; + } +} + #define MIFARE_CMD_AUTH_KEY_A 0x60 #define MIFARE_CMD_AUTH_KEY_B 0x61 #define MIFARE_CMD_HEADER 2 @@ -744,11 +767,11 @@ static int pn544_hci_complete_target_discovered(struct nfc_shdlc *shdlc, */ static int pn544_hci_data_exchange(struct nfc_shdlc *shdlc, struct nfc_target *target, - struct sk_buff *skb, - struct sk_buff **res_skb) + struct sk_buff *skb, data_exchange_cb_t cb, + void *cb_context) { + struct pn544_hci_info *info = nfc_shdlc_get_clientdata(shdlc); struct nfc_hci_dev *hdev = nfc_shdlc_get_hci_dev(shdlc); - int r; pr_info(DRIVER_DESC ": %s for gate=%d\n", __func__, target->hci_reader_gate); @@ -773,25 +796,29 @@ static int pn544_hci_data_exchange(struct nfc_shdlc *shdlc, memcpy(data, uid, MIFARE_UID_LEN); } - return nfc_hci_send_cmd(hdev, target->hci_reader_gate, - PN544_MIFARE_CMD, - skb->data, skb->len, res_skb); + return nfc_hci_send_cmd_async(hdev, + target->hci_reader_gate, + PN544_MIFARE_CMD, + skb->data, skb->len, + cb, cb_context); } else return 1; case PN544_RF_READER_F_GATE: *skb_push(skb, 1) = 0; *skb_push(skb, 1) = 0; - r = nfc_hci_send_cmd(hdev, target->hci_reader_gate, - PN544_FELICA_RAW, - skb->data, skb->len, res_skb); - if (r == 0) - skb_pull(*res_skb, 1); - return r; + info->async_cb_type = PN544_CB_TYPE_READER_F; + info->async_cb = cb; + info->async_cb_context = cb_context; + + return nfc_hci_send_cmd_async(hdev, target->hci_reader_gate, + PN544_FELICA_RAW, skb->data, + skb->len, + pn544_hci_data_exchange_cb, info); case PN544_RF_READER_JEWEL_GATE: - return nfc_hci_send_cmd(hdev, target->hci_reader_gate, - PN544_JEWEL_RAW_CMD, - skb->data, skb->len, res_skb); + return nfc_hci_send_cmd_async(hdev, target->hci_reader_gate, + PN544_JEWEL_RAW_CMD, skb->data, + skb->len, cb, cb_context); default: return 1; } diff --git a/include/net/nfc/hci.h b/include/net/nfc/hci.h index 54ba2caab4a6..6cee6e21fc46 100644 --- a/include/net/nfc/hci.h +++ b/include/net/nfc/hci.h @@ -38,8 +38,8 @@ struct nfc_hci_ops { int (*complete_target_discovered) (struct nfc_hci_dev *hdev, u8 gate, struct nfc_target *target); int (*data_exchange) (struct nfc_hci_dev *hdev, - struct nfc_target *target, - struct sk_buff *skb, struct sk_buff **res_skb); + struct nfc_target *target, struct sk_buff *skb, + data_exchange_cb_t cb, void *cb_context); int (*check_presence)(struct nfc_hci_dev *hdev, struct nfc_target *target); }; @@ -103,6 +103,10 @@ struct nfc_hci_dev { u8 hw_mpw; u8 hw_software; u8 hw_bsid; + + int async_cb_type; + data_exchange_cb_t async_cb; + void *async_cb_context; }; /* hci device allocation */ diff --git a/include/net/nfc/shdlc.h b/include/net/nfc/shdlc.h index 342427362989..fe5e19829352 100644 --- a/include/net/nfc/shdlc.h +++ b/include/net/nfc/shdlc.h @@ -34,8 +34,8 @@ struct nfc_shdlc_ops { int (*complete_target_discovered) (struct nfc_shdlc *shdlc, u8 gate, struct nfc_target *target); int (*data_exchange) (struct nfc_shdlc *shdlc, - struct nfc_target *target, - struct sk_buff *skb, struct sk_buff **res_skb); + struct nfc_target *target, struct sk_buff *skb, + data_exchange_cb_t cb, void *cb_context); int (*check_presence)(struct nfc_shdlc *shdlc, struct nfc_target *target); }; diff --git a/net/nfc/hci/core.c b/net/nfc/hci/core.c index e387c86e0cc7..dc57e3dc15a4 100644 --- a/net/nfc/hci/core.c +++ b/net/nfc/hci/core.c @@ -537,13 +537,37 @@ static void hci_deactivate_target(struct nfc_dev *nfc_dev, { } +#define HCI_CB_TYPE_TRANSCEIVE 1 + +static void hci_transceive_cb(void *context, struct sk_buff *skb, int err) +{ + struct nfc_hci_dev *hdev = context; + + switch (hdev->async_cb_type) { + case HCI_CB_TYPE_TRANSCEIVE: + /* + * TODO: Check RF Error indicator to make sure data is valid. + * It seems that HCI cmd can complete without error, but data + * can be invalid if an RF error occured? Ignore for now. + */ + if (err == 0) + skb_trim(skb, skb->len - 1); /* RF Err ind */ + + hdev->async_cb(hdev->async_cb_context, skb, err); + break; + default: + if (err == 0) + kfree_skb(skb); + break; + } +} + static int hci_transceive(struct nfc_dev *nfc_dev, struct nfc_target *target, struct sk_buff *skb, data_exchange_cb_t cb, void *cb_context) { struct nfc_hci_dev *hdev = nfc_get_drvdata(nfc_dev); int r; - struct sk_buff *res_skb = NULL; pr_debug("target_idx=%d\n", target->idx); @@ -551,40 +575,37 @@ static int hci_transceive(struct nfc_dev *nfc_dev, struct nfc_target *target, case NFC_HCI_RF_READER_A_GATE: case NFC_HCI_RF_READER_B_GATE: if (hdev->ops->data_exchange) { - r = hdev->ops->data_exchange(hdev, target, skb, - &res_skb); + r = hdev->ops->data_exchange(hdev, target, skb, cb, + cb_context); if (r <= 0) /* handled */ break; } *skb_push(skb, 1) = 0; /* CTR, see spec:10.2.2.1 */ - r = nfc_hci_send_cmd(hdev, target->hci_reader_gate, - NFC_HCI_WR_XCHG_DATA, - skb->data, skb->len, &res_skb); - /* - * TODO: Check RF Error indicator to make sure data is valid. - * It seems that HCI cmd can complete without error, but data - * can be invalid if an RF error occured? Ignore for now. - */ - if (r == 0) - skb_trim(res_skb, res_skb->len - 1); /* RF Err ind */ + + hdev->async_cb_type = HCI_CB_TYPE_TRANSCEIVE; + hdev->async_cb = cb; + hdev->async_cb_context = cb_context; + + r = nfc_hci_send_cmd_async(hdev, target->hci_reader_gate, + NFC_HCI_WR_XCHG_DATA, skb->data, + skb->len, hci_transceive_cb, hdev); break; default: if (hdev->ops->data_exchange) { - r = hdev->ops->data_exchange(hdev, target, skb, - &res_skb); + r = hdev->ops->data_exchange(hdev, target, skb, cb, + cb_context); if (r == 1) r = -ENOTSUPP; } else r = -ENOTSUPP; + break; } kfree_skb(skb); - cb(cb_context, res_skb, r); - - return 0; + return r; } static int hci_check_presence(struct nfc_dev *nfc_dev, diff --git a/net/nfc/hci/shdlc.c b/net/nfc/hci/shdlc.c index 9357ba7362f6..c63af7d3e859 100644 --- a/net/nfc/hci/shdlc.c +++ b/net/nfc/hci/shdlc.c @@ -777,12 +777,13 @@ static int nfc_shdlc_complete_target_discovered(struct nfc_hci_dev *hdev, static int nfc_shdlc_data_exchange(struct nfc_hci_dev *hdev, struct nfc_target *target, struct sk_buff *skb, - struct sk_buff **res_skb) + data_exchange_cb_t cb, void *cb_context) { struct nfc_shdlc *shdlc = nfc_hci_get_clientdata(hdev); if (shdlc->ops->data_exchange) - return shdlc->ops->data_exchange(shdlc, target, skb, res_skb); + return shdlc->ops->data_exchange(shdlc, target, skb, cb, + cb_context); return -EPERM; }