NFC: st21nfca: Adding support for secure element

st21nfca has 1 physical SWP line and can support up to 2 secure elements
(UICC & eSE) thanks to an external switch managed with a gpio.

The platform integrator needs to specify thanks to 2 initialization
properties, uicc-present and ese-present, if it is suppose to have uicc
and/or ese. Of course if the platform does not have an external switch,
only one kind of secure element can be supported. Those parameters are
under platform integrator responsibilities.

During initialization, the white_list will be set according to those
parameters.

The discovery_se function will assume a secure element is physically
present according to uicc-present and ese-present values and will add it
to the secure element list. On ese activation, the atr is retrieved to
calculate a command exchange timeout based on the first atr(TB) value.

The se_io will allow to transfer data over SWP. 2 kind of events may appear
after a data is sent over:
- ST21NFCA_EVT_TRANSMIT_DATA when receiving an apdu answer
- ST21NFCA_EVT_WTX_REQUEST when the secure element needs more time than
expected to compute a command. If this timeout expired, a first recovery
tentative consist to send a simple software reset proprietary command.
If this tentative still fail, a second recovery tentative consist to send
a hardware reset proprietary command.
This function is only relevant for eSE like secure element.

This patch also change the way a pipe is referenced. There can be
different pipe connected to the same gate with different host destination
(ex: CONNECTIVITY). In order to keep host information every pipe are
reference with a tuple (gate, host). In order to reduce changes, we are
keeping unchanged the way a gate is addressed on the Terminal Host.
However, this is working because we consider the apdu reader gate is only
present on the eSE slot also the connectivity gate cannot give a reliable
value; it will give the latest stored pipe value.

Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 390 insertions, 0 deletions

diff --git a/drivers/nfc/st21nfca/st21nfca_se.c b/drivers/nfc/st21nfca/st21nfca_se.c
new file mode 100644
index 000000000000..9b93d3904ab5
--- /dev/null
+++ b/drivers/nfc/st21nfca/st21nfca_se.c
@@ -0,0 +1,390 @@
+/*
+ * Copyright (C) 2014  STMicroelectronics SAS. 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 <net/nfc/hci.h>
+
+#include "st21nfca.h"
+#include "st21nfca_se.h"
+
+#define ST21NFCA_EVT_UICC_ACTIVATE		0x10
+#define ST21NFCA_EVT_UICC_DEACTIVATE	0x13
+#define ST21NFCA_EVT_SE_HARD_RESET		0x20
+#define ST21NFCA_EVT_SE_SOFT_RESET		0x11
+#define ST21NFCA_EVT_SE_END_OF_APDU_TRANSFER	0x21
+#define ST21NFCA_EVT_SE_ACTIVATE		0x22
+#define ST21NFCA_EVT_SE_DEACTIVATE		0x23
+
+#define ST21NFCA_EVT_TRANSMIT_DATA		0x10
+#define ST21NFCA_EVT_WTX_REQUEST		0x11
+
+#define ST21NFCA_EVT_CONNECTIVITY		0x10
+#define ST21NFCA_EVT_TRANSACTION		0x12
+
+#define ST21NFCA_ESE_HOST_ID			0xc0
+
+#define ST21NFCA_SE_TO_HOT_PLUG			1000
+/* Connectivity pipe only */
+#define ST21NFCA_SE_COUNT_PIPE_UICC		0x01
+/* Connectivity + APDU Reader pipe */
+#define ST21NFCA_SE_COUNT_PIPE_EMBEDDED	0x02
+
+#define ST21NFCA_SE_MODE_OFF			0x00
+#define ST21NFCA_SE_MODE_ON				0x01
+
+#define ST21NFCA_PARAM_ATR				0x01
+#define ST21NFCA_ATR_DEFAULT_BWI		0x04
+
+/*
+ * WT = 2^BWI/10[s], convert into msecs and add a secure
+ * room by increasing by 2 this timeout
+ */
+#define ST21NFCA_BWI_TO_TIMEOUT(x)		((1 << x) * 200)
+#define ST21NFCA_ATR_GET_Y_FROM_TD(x)	(x >> 4)
+
+/* If TA is present bit 0 is set */
+#define ST21NFCA_ATR_TA_PRESENT(x) (x & 0x01)
+/* If TB is present bit 1 is set */
+#define ST21NFCA_ATR_TB_PRESENT(x) (x & 0x02)
+
+static u8 st21nfca_se_get_bwi(struct nfc_hci_dev *hdev)
+{
+	int i;
+	u8 td;
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	/* Bits 8 to 5 of the first TB for T=1 encode BWI from zero to nine */
+	for (i = 1; i < ST21NFCA_ESE_MAX_LENGTH; i++) {
+		td = ST21NFCA_ATR_GET_Y_FROM_TD(info->se_info.atr[i]);
+		if (ST21NFCA_ATR_TA_PRESENT(td))
+			i++;
+		if (ST21NFCA_ATR_TB_PRESENT(td)) {
+			i++;
+			return info->se_info.atr[i] >> 4;
+		}
+	}
+	return ST21NFCA_ATR_DEFAULT_BWI;
+}
+
+static void st21nfca_se_get_atr(struct nfc_hci_dev *hdev)
+{
+	int r;
+	struct sk_buff *skb;
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	r = nfc_hci_get_param(hdev, ST21NFCA_APDU_READER_GATE,
+			ST21NFCA_PARAM_ATR, &skb);
+	if (r < 0)
+		return;
+
+	if (skb->len <= ST21NFCA_ESE_MAX_LENGTH) {
+		memcpy(info->se_info.atr, skb->data, skb->len);
+		info->se_info.wt_timeout =
+			ST21NFCA_BWI_TO_TIMEOUT(st21nfca_se_get_bwi(hdev));
+	}
+	kfree_skb(skb);
+}
+
+static int st21nfca_hci_control_se(struct nfc_hci_dev *hdev, u32 se_idx,
+				u8 state)
+{
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+	int r;
+	struct sk_buff *sk_host_list;
+	u8 se_event, host_id;
+
+	switch (se_idx) {
+	case NFC_HCI_UICC_HOST_ID:
+		se_event = (state == ST21NFCA_SE_MODE_ON ?
+					ST21NFCA_EVT_UICC_ACTIVATE :
+					ST21NFCA_EVT_UICC_DEACTIVATE);
+
+		info->se_info.count_pipes = 0;
+		info->se_info.expected_pipes = ST21NFCA_SE_COUNT_PIPE_UICC;
+		break;
+	case ST21NFCA_ESE_HOST_ID:
+		se_event = (state == ST21NFCA_SE_MODE_ON ?
+					ST21NFCA_EVT_SE_ACTIVATE :
+					ST21NFCA_EVT_SE_DEACTIVATE);
+
+		info->se_info.count_pipes = 0;
+		info->se_info.expected_pipes = ST21NFCA_SE_COUNT_PIPE_EMBEDDED;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	/*
+	 * Wait for an EVT_HOT_PLUG in order to
+	 * retrieve a relevant host list.
+	 */
+	reinit_completion(&info->se_info.req_completion);
+	r = nfc_hci_send_event(hdev, ST21NFCA_DEVICE_MGNT_GATE, se_event,
+			       NULL, 0);
+	if (r < 0)
+		return r;
+
+	mod_timer(&info->se_info.se_active_timer, jiffies +
+		msecs_to_jiffies(ST21NFCA_SE_TO_HOT_PLUG));
+	info->se_info.se_active = true;
+
+	/* Ignore return value and check in any case the host_list */
+	wait_for_completion_interruptible(&info->se_info.req_completion);
+
+	r = nfc_hci_get_param(hdev, NFC_HCI_ADMIN_GATE,
+			NFC_HCI_ADMIN_HOST_LIST,
+			&sk_host_list);
+	if (r < 0)
+		return r;
+
+	host_id = sk_host_list->data[sk_host_list->len - 1];
+	kfree_skb(sk_host_list);
+
+	if (state == ST21NFCA_SE_MODE_ON && host_id == se_idx)
+		return se_idx;
+	else if (state == ST21NFCA_SE_MODE_OFF && host_id != se_idx)
+		return se_idx;
+
+	return -1;
+}
+
+int st21nfca_hci_discover_se(struct nfc_hci_dev *hdev)
+{
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+	int se_count = 0;
+
+	if (info->se_status->is_uicc_present) {
+		nfc_add_se(hdev->ndev, NFC_HCI_UICC_HOST_ID, NFC_SE_UICC);
+		se_count++;
+	}
+
+	if (info->se_status->is_ese_present) {
+		nfc_add_se(hdev->ndev, ST21NFCA_ESE_HOST_ID, NFC_SE_EMBEDDED);
+		se_count++;
+	}
+
+	return !se_count;
+}
+EXPORT_SYMBOL(st21nfca_hci_discover_se);
+
+int st21nfca_hci_enable_se(struct nfc_hci_dev *hdev, u32 se_idx)
+{
+	int r;
+
+	/*
+	 * According to upper layer, se_idx == NFC_SE_UICC when
+	 * info->se_status->is_uicc_enable is true should never happen.
+	 * Same for eSE.
+	 */
+	r = st21nfca_hci_control_se(hdev, se_idx, ST21NFCA_SE_MODE_ON);
+
+	if (r == ST21NFCA_ESE_HOST_ID) {
+		st21nfca_se_get_atr(hdev);
+		r = nfc_hci_send_event(hdev, ST21NFCA_APDU_READER_GATE,
+				ST21NFCA_EVT_SE_SOFT_RESET, NULL, 0);
+		if (r < 0)
+			return r;
+	} else if (r < 0) {
+		/*
+		 * The activation tentative failed, the secure element
+		 * is not connected. Remove from the list.
+		 */
+		nfc_remove_se(hdev->ndev, se_idx);
+		return r;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(st21nfca_hci_enable_se);
+
+int st21nfca_hci_disable_se(struct nfc_hci_dev *hdev, u32 se_idx)
+{
+	int r;
+
+	/*
+	 * According to upper layer, se_idx == NFC_SE_UICC when
+	 * info->se_status->is_uicc_enable is true should never happen
+	 * Same for eSE.
+	 */
+	r = st21nfca_hci_control_se(hdev, se_idx, ST21NFCA_SE_MODE_OFF);
+	if (r < 0)
+		return r;
+
+	return 0;
+}
+EXPORT_SYMBOL(st21nfca_hci_disable_se);
+
+int st21nfca_hci_se_io(struct nfc_hci_dev *hdev, u32 se_idx,
+			u8 *apdu, size_t apdu_length,
+			se_io_cb_t cb, void *cb_context)
+{
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	pr_debug("se_io %x\n", se_idx);
+
+	switch (se_idx) {
+	case ST21NFCA_ESE_HOST_ID:
+		info->se_info.cb = cb;
+		info->se_info.cb_context = cb_context;
+		mod_timer(&info->se_info.bwi_timer, jiffies +
+			  msecs_to_jiffies(info->se_info.wt_timeout));
+		info->se_info.bwi_active = true;
+		return nfc_hci_send_event(hdev, ST21NFCA_APDU_READER_GATE,
+					ST21NFCA_EVT_TRANSMIT_DATA,
+					apdu, apdu_length);
+	default:
+		return -ENODEV;
+	}
+}
+EXPORT_SYMBOL(st21nfca_hci_se_io);
+
+static void st21nfca_se_wt_timeout(unsigned long data)
+{
+	/*
+	 * No answer from the secure element
+	 * within the defined timeout.
+	 * Let's send a reset request as recovery procedure.
+	 * According to the situation, we first try to send a software reset
+	 * to the secure element. If the next command is still not
+	 * answering in time, we send to the CLF a secure element hardware
+	 * reset request.
+	 */
+	/* hardware reset managed through VCC_UICC_OUT power supply */
+	u8 param = 0x01;
+	struct st21nfca_hci_info *info = (struct st21nfca_hci_info *) data;
+
+	pr_debug("\n");
+
+	info->se_info.bwi_active = false;
+
+	if (!info->se_info.xch_error) {
+		info->se_info.xch_error = true;
+		nfc_hci_send_event(info->hdev, ST21NFCA_APDU_READER_GATE,
+				ST21NFCA_EVT_SE_SOFT_RESET, NULL, 0);
+	} else {
+		info->se_info.xch_error = false;
+		nfc_hci_send_event(info->hdev, ST21NFCA_DEVICE_MGNT_GATE,
+				ST21NFCA_EVT_SE_HARD_RESET, &param, 1);
+	}
+	info->se_info.cb(info->se_info.cb_context, NULL, 0, -ETIME);
+}
+
+static void st21nfca_se_activation_timeout(unsigned long data)
+{
+	struct st21nfca_hci_info *info = (struct st21nfca_hci_info *) data;
+
+	pr_debug("\n");
+
+	info->se_info.se_active = false;
+
+	complete(&info->se_info.req_completion);
+}
+
+/*
+ * Returns:
+ * <= 0: driver handled the event, skb consumed
+ *    1: driver does not handle the event, please do standard processing
+ */
+int st21nfca_connectivity_event_received(struct nfc_hci_dev *hdev, u8 host,
+				u8 event, struct sk_buff *skb)
+{
+	int r = 0;
+
+	pr_debug("connectivity gate event: %x\n", event);
+
+	switch (event) {
+	case ST21NFCA_EVT_CONNECTIVITY:
+		break;
+	case ST21NFCA_EVT_TRANSACTION:
+		break;
+	default:
+		return 1;
+	}
+	kfree_skb(skb);
+	return r;
+}
+EXPORT_SYMBOL(st21nfca_connectivity_event_received);
+
+int st21nfca_apdu_reader_event_received(struct nfc_hci_dev *hdev,
+					u8 event, struct sk_buff *skb)
+{
+	int r = 0;
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	pr_debug("apdu reader gate event: %x\n", event);
+
+	switch (event) {
+	case ST21NFCA_EVT_TRANSMIT_DATA:
+		del_timer_sync(&info->se_info.bwi_timer);
+		info->se_info.bwi_active = false;
+		r = nfc_hci_send_event(hdev, ST21NFCA_DEVICE_MGNT_GATE,
+				ST21NFCA_EVT_SE_END_OF_APDU_TRANSFER, NULL, 0);
+		if (r < 0)
+			goto exit;
+
+		info->se_info.cb(info->se_info.cb_context,
+			skb->data, skb->len, 0);
+		break;
+	case ST21NFCA_EVT_WTX_REQUEST:
+		mod_timer(&info->se_info.bwi_timer, jiffies +
+				msecs_to_jiffies(info->se_info.wt_timeout));
+		break;
+	}
+
+exit:
+	kfree_skb(skb);
+	return r;
+}
+EXPORT_SYMBOL(st21nfca_apdu_reader_event_received);
+
+void st21nfca_se_init(struct nfc_hci_dev *hdev)
+{
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	init_completion(&info->se_info.req_completion);
+	/* initialize timers */
+	init_timer(&info->se_info.bwi_timer);
+	info->se_info.bwi_timer.data = (unsigned long)info;
+	info->se_info.bwi_timer.function = st21nfca_se_wt_timeout;
+	info->se_info.bwi_active = false;
+
+	init_timer(&info->se_info.se_active_timer);
+	info->se_info.se_active_timer.data = (unsigned long)info;
+	info->se_info.se_active_timer.function = st21nfca_se_activation_timeout;
+	info->se_info.se_active = false;
+
+	info->se_info.count_pipes = 0;
+	info->se_info.expected_pipes = 0;
+
+	info->se_info.xch_error = false;
+
+	info->se_info.wt_timeout =
+			ST21NFCA_BWI_TO_TIMEOUT(ST21NFCA_ATR_DEFAULT_BWI);
+}
+EXPORT_SYMBOL(st21nfca_se_init);
+
+void st21nfca_se_deinit(struct nfc_hci_dev *hdev)
+{
+	struct st21nfca_hci_info *info = nfc_hci_get_clientdata(hdev);
+
+	if (info->se_info.bwi_active)
+		del_timer_sync(&info->se_info.bwi_timer);
+	if (info->se_info.se_active)
+		del_timer_sync(&info->se_info.se_active_timer);
+
+	info->se_info.bwi_active = false;
+	info->se_info.se_active = false;
+}
+EXPORT_SYMBOL(st21nfca_se_deinit);