diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-12 18:07:07 -0800 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2012-12-12 18:07:07 -0800 |
commit | 6be35c700f742e911ecedd07fcc43d4439922334 (patch) | |
tree | ca9f37214d204465fcc2d79c82efd291e357c53c /drivers/nfc/pn544/i2c.c | |
parent | e37aa63e87bd581f9be5555ed0ba83f5295c92fc (diff) | |
parent | 520dfe3a3645257bf83660f672c47f8558f3d4c4 (diff) | |
download | blackbird-op-linux-6be35c700f742e911ecedd07fcc43d4439922334.tar.gz blackbird-op-linux-6be35c700f742e911ecedd07fcc43d4439922334.zip |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next
Pull networking changes from David Miller:
1) Allow to dump, monitor, and change the bridge multicast database
using netlink. From Cong Wang.
2) RFC 5961 TCP blind data injection attack mitigation, from Eric
Dumazet.
3) Networking user namespace support from Eric W. Biederman.
4) tuntap/virtio-net multiqueue support by Jason Wang.
5) Support for checksum offload of encapsulated packets (basically,
tunneled traffic can still be checksummed by HW). From Joseph
Gasparakis.
6) Allow BPF filter access to VLAN tags, from Eric Dumazet and
Daniel Borkmann.
7) Bridge port parameters over netlink and BPDU blocking support
from Stephen Hemminger.
8) Improve data access patterns during inet socket demux by rearranging
socket layout, from Eric Dumazet.
9) TIPC protocol updates and cleanups from Ying Xue, Paul Gortmaker, and
Jon Maloy.
10) Update TCP socket hash sizing to be more in line with current day
realities. The existing heurstics were choosen a decade ago.
From Eric Dumazet.
11) Fix races, queue bloat, and excessive wakeups in ATM and
associated drivers, from Krzysztof Mazur and David Woodhouse.
12) Support DOVE (Distributed Overlay Virtual Ethernet) extensions
in VXLAN driver, from David Stevens.
13) Add "oops_only" mode to netconsole, from Amerigo Wang.
14) Support set and query of VEB/VEPA bridge mode via PF_BRIDGE, also
allow DCB netlink to work on namespaces other than the initial
namespace. From John Fastabend.
15) Support PTP in the Tigon3 driver, from Matt Carlson.
16) tun/vhost zero copy fixes and improvements, plus turn it on
by default, from Michael S. Tsirkin.
17) Support per-association statistics in SCTP, from Michele
Baldessari.
And many, many, driver updates, cleanups, and improvements. Too
numerous to mention individually.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1722 commits)
net/mlx4_en: Add support for destination MAC in steering rules
net/mlx4_en: Use generic etherdevice.h functions.
net: ethtool: Add destination MAC address to flow steering API
bridge: add support of adding and deleting mdb entries
bridge: notify mdb changes via netlink
ndisc: Unexport ndisc_{build,send}_skb().
uapi: add missing netconf.h to export list
pkt_sched: avoid requeues if possible
solos-pci: fix double-free of TX skb in DMA mode
bnx2: Fix accidental reversions.
bna: Driver Version Updated to 3.1.2.1
bna: Firmware update
bna: Add RX State
bna: Rx Page Based Allocation
bna: TX Intr Coalescing Fix
bna: Tx and Rx Optimizations
bna: Code Cleanup and Enhancements
ath9k: check pdata variable before dereferencing it
ath5k: RX timestamp is reported at end of frame
ath9k_htc: RX timestamp is reported at end of frame
...
Diffstat (limited to 'drivers/nfc/pn544/i2c.c')
-rw-r--r-- | drivers/nfc/pn544/i2c.c | 500 |
1 files changed, 500 insertions, 0 deletions
diff --git a/drivers/nfc/pn544/i2c.c b/drivers/nfc/pn544/i2c.c new file mode 100644 index 000000000000..7da9071b68b6 --- /dev/null +++ b/drivers/nfc/pn544/i2c.c @@ -0,0 +1,500 @@ +/* + * I2C Link Layer for PN544 HCI based Driver + * + * Copyright (C) 2012 Intel Corporation. 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, write to the + * Free Software Foundation, Inc., + * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + */ + +#include <linux/crc-ccitt.h> +#include <linux/module.h> +#include <linux/i2c.h> +#include <linux/gpio.h> +#include <linux/miscdevice.h> +#include <linux/interrupt.h> +#include <linux/delay.h> + +#include <linux/platform_data/pn544.h> + +#include <net/nfc/hci.h> +#include <net/nfc/llc.h> + +#include "pn544.h" + +#define PN544_I2C_FRAME_HEADROOM 1 +#define PN544_I2C_FRAME_TAILROOM 2 + +/* framing in HCI mode */ +#define PN544_HCI_I2C_LLC_LEN 1 +#define PN544_HCI_I2C_LLC_CRC 2 +#define PN544_HCI_I2C_LLC_LEN_CRC (PN544_HCI_I2C_LLC_LEN + \ + PN544_HCI_I2C_LLC_CRC) +#define PN544_HCI_I2C_LLC_MIN_SIZE (1 + PN544_HCI_I2C_LLC_LEN_CRC) +#define PN544_HCI_I2C_LLC_MAX_PAYLOAD 29 +#define PN544_HCI_I2C_LLC_MAX_SIZE (PN544_HCI_I2C_LLC_LEN_CRC + 1 + \ + PN544_HCI_I2C_LLC_MAX_PAYLOAD) + +static struct i2c_device_id pn544_hci_i2c_id_table[] = { + {"pn544", 0}, + {} +}; + +MODULE_DEVICE_TABLE(i2c, pn544_hci_i2c_id_table); + +#define PN544_HCI_I2C_DRIVER_NAME "pn544_hci_i2c" + +struct pn544_i2c_phy { + struct i2c_client *i2c_dev; + struct nfc_hci_dev *hdev; + + unsigned int gpio_en; + unsigned int gpio_irq; + unsigned int gpio_fw; + unsigned int en_polarity; + + int powered; + + int hard_fault; /* + * < 0 if hardware error occured (e.g. i2c err) + * and prevents normal operation. + */ +}; + +#define I2C_DUMP_SKB(info, skb) \ +do { \ + pr_debug("%s:\n", info); \ + print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \ + 16, 1, (skb)->data, (skb)->len, 0); \ +} while (0) + +static void pn544_hci_i2c_platform_init(struct pn544_i2c_phy *phy) +{ + int polarity, retry, ret; + char rset_cmd[] = { 0x05, 0xF9, 0x04, 0x00, 0xC3, 0xE5 }; + int count = sizeof(rset_cmd); + + pr_info(DRIVER_DESC ": %s\n", __func__); + dev_info(&phy->i2c_dev->dev, "Detecting nfc_en polarity\n"); + + /* Disable fw download */ + gpio_set_value(phy->gpio_fw, 0); + + for (polarity = 0; polarity < 2; polarity++) { + phy->en_polarity = polarity; + retry = 3; + while (retry--) { + /* power off */ + gpio_set_value(phy->gpio_en, !phy->en_polarity); + usleep_range(10000, 15000); + + /* power on */ + gpio_set_value(phy->gpio_en, phy->en_polarity); + usleep_range(10000, 15000); + + /* send reset */ + dev_dbg(&phy->i2c_dev->dev, "Sending reset cmd\n"); + ret = i2c_master_send(phy->i2c_dev, rset_cmd, count); + if (ret == count) { + dev_info(&phy->i2c_dev->dev, + "nfc_en polarity : active %s\n", + (polarity == 0 ? "low" : "high")); + goto out; + } + } + } + + dev_err(&phy->i2c_dev->dev, + "Could not detect nfc_en polarity, fallback to active high\n"); + +out: + gpio_set_value(phy->gpio_en, !phy->en_polarity); +} + +static int pn544_hci_i2c_enable(void *phy_id) +{ + struct pn544_i2c_phy *phy = phy_id; + + pr_info(DRIVER_DESC ": %s\n", __func__); + + gpio_set_value(phy->gpio_fw, 0); + gpio_set_value(phy->gpio_en, phy->en_polarity); + usleep_range(10000, 15000); + + phy->powered = 1; + + return 0; +} + +static void pn544_hci_i2c_disable(void *phy_id) +{ + struct pn544_i2c_phy *phy = phy_id; + + pr_info(DRIVER_DESC ": %s\n", __func__); + + gpio_set_value(phy->gpio_fw, 0); + gpio_set_value(phy->gpio_en, !phy->en_polarity); + usleep_range(10000, 15000); + + gpio_set_value(phy->gpio_en, phy->en_polarity); + usleep_range(10000, 15000); + + gpio_set_value(phy->gpio_en, !phy->en_polarity); + usleep_range(10000, 15000); + + phy->powered = 0; +} + +static void pn544_hci_i2c_add_len_crc(struct sk_buff *skb) +{ + u16 crc; + int len; + + len = skb->len + 2; + *skb_push(skb, 1) = len; + + crc = crc_ccitt(0xffff, skb->data, skb->len); + crc = ~crc; + *skb_put(skb, 1) = crc & 0xff; + *skb_put(skb, 1) = crc >> 8; +} + +static void pn544_hci_i2c_remove_len_crc(struct sk_buff *skb) +{ + skb_pull(skb, PN544_I2C_FRAME_HEADROOM); + skb_trim(skb, PN544_I2C_FRAME_TAILROOM); +} + +/* + * Writing a frame must not return the number of written bytes. + * It must return either zero for success, or <0 for error. + * In addition, it must not alter the skb + */ +static int pn544_hci_i2c_write(void *phy_id, struct sk_buff *skb) +{ + int r; + struct pn544_i2c_phy *phy = phy_id; + struct i2c_client *client = phy->i2c_dev; + + if (phy->hard_fault != 0) + return phy->hard_fault; + + usleep_range(3000, 6000); + + pn544_hci_i2c_add_len_crc(skb); + + I2C_DUMP_SKB("i2c frame written", skb); + + r = i2c_master_send(client, skb->data, skb->len); + + if (r == -EREMOTEIO) { /* Retry, chip was in standby */ + usleep_range(6000, 10000); + r = i2c_master_send(client, skb->data, skb->len); + } + + if (r >= 0) { + if (r != skb->len) + r = -EREMOTEIO; + else + r = 0; + } + + pn544_hci_i2c_remove_len_crc(skb); + + return r; +} + +static int check_crc(u8 *buf, int buflen) +{ + int len; + u16 crc; + + len = buf[0] + 1; + crc = crc_ccitt(0xffff, buf, len - 2); + crc = ~crc; + + if (buf[len - 2] != (crc & 0xff) || buf[len - 1] != (crc >> 8)) { + pr_err(PN544_HCI_I2C_DRIVER_NAME + ": CRC error 0x%x != 0x%x 0x%x\n", + crc, buf[len - 1], buf[len - 2]); + + pr_info(DRIVER_DESC ": %s : BAD CRC\n", __func__); + print_hex_dump(KERN_DEBUG, "crc: ", DUMP_PREFIX_NONE, + 16, 2, buf, buflen, false); + return -EPERM; + } + return 0; +} + +/* + * Reads an shdlc frame and returns it in a newly allocated sk_buff. Guarantees + * that i2c bus will be flushed and that next read will start on a new frame. + * returned skb contains only LLC header and payload. + * returns: + * -EREMOTEIO : i2c read error (fatal) + * -EBADMSG : frame was incorrect and discarded + * -ENOMEM : cannot allocate skb, frame dropped + */ +static int pn544_hci_i2c_read(struct pn544_i2c_phy *phy, struct sk_buff **skb) +{ + int r; + u8 len; + u8 tmp[PN544_HCI_I2C_LLC_MAX_SIZE - 1]; + struct i2c_client *client = phy->i2c_dev; + + r = i2c_master_recv(client, &len, 1); + if (r != 1) { + dev_err(&client->dev, "cannot read len byte\n"); + return -EREMOTEIO; + } + + if ((len < (PN544_HCI_I2C_LLC_MIN_SIZE - 1)) || + (len > (PN544_HCI_I2C_LLC_MAX_SIZE - 1))) { + dev_err(&client->dev, "invalid len byte\n"); + r = -EBADMSG; + goto flush; + } + + *skb = alloc_skb(1 + len, GFP_KERNEL); + if (*skb == NULL) { + r = -ENOMEM; + goto flush; + } + + *skb_put(*skb, 1) = len; + + r = i2c_master_recv(client, skb_put(*skb, len), len); + if (r != len) { + kfree_skb(*skb); + return -EREMOTEIO; + } + + I2C_DUMP_SKB("i2c frame read", *skb); + + r = check_crc((*skb)->data, (*skb)->len); + if (r != 0) { + kfree_skb(*skb); + r = -EBADMSG; + goto flush; + } + + skb_pull(*skb, 1); + skb_trim(*skb, (*skb)->len - 2); + + usleep_range(3000, 6000); + + return 0; + +flush: + if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0) + r = -EREMOTEIO; + + usleep_range(3000, 6000); + + return r; +} + +/* + * Reads an shdlc frame from the chip. This is not as straightforward as it + * seems. There are cases where we could loose the frame start synchronization. + * The frame format is len-data-crc, and corruption can occur anywhere while + * transiting on i2c bus, such that we could read an invalid len. + * In order to recover synchronization with the next frame, we must be sure + * to read the real amount of data without using the len byte. We do this by + * assuming the following: + * - the chip will always present only one single complete frame on the bus + * before triggering the interrupt + * - the chip will not present a new frame until we have completely read + * the previous one (or until we have handled the interrupt). + * The tricky case is when we read a corrupted len that is less than the real + * len. We must detect this here in order to determine that we need to flush + * the bus. This is the reason why we check the crc here. + */ +static irqreturn_t pn544_hci_i2c_irq_thread_fn(int irq, void *phy_id) +{ + struct pn544_i2c_phy *phy = phy_id; + struct i2c_client *client; + struct sk_buff *skb = NULL; + int r; + + if (!phy || irq != phy->i2c_dev->irq) { + WARN_ON_ONCE(1); + return IRQ_NONE; + } + + client = phy->i2c_dev; + dev_dbg(&client->dev, "IRQ\n"); + + if (phy->hard_fault != 0) + return IRQ_HANDLED; + + r = pn544_hci_i2c_read(phy, &skb); + if (r == -EREMOTEIO) { + phy->hard_fault = r; + + nfc_hci_recv_frame(phy->hdev, NULL); + + return IRQ_HANDLED; + } else if ((r == -ENOMEM) || (r == -EBADMSG)) { + return IRQ_HANDLED; + } + + nfc_hci_recv_frame(phy->hdev, skb); + + return IRQ_HANDLED; +} + +static struct nfc_phy_ops i2c_phy_ops = { + .write = pn544_hci_i2c_write, + .enable = pn544_hci_i2c_enable, + .disable = pn544_hci_i2c_disable, +}; + +static int __devinit pn544_hci_i2c_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct pn544_i2c_phy *phy; + struct pn544_nfc_platform_data *pdata; + int r = 0; + + dev_dbg(&client->dev, "%s\n", __func__); + dev_dbg(&client->dev, "IRQ: %d\n", client->irq); + + if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) { + dev_err(&client->dev, "Need I2C_FUNC_I2C\n"); + return -ENODEV; + } + + phy = kzalloc(sizeof(struct pn544_i2c_phy), GFP_KERNEL); + if (!phy) { + dev_err(&client->dev, + "Cannot allocate memory for pn544 i2c phy.\n"); + r = -ENOMEM; + goto err_phy_alloc; + } + + phy->i2c_dev = client; + i2c_set_clientdata(client, phy); + + pdata = client->dev.platform_data; + if (pdata == NULL) { + dev_err(&client->dev, "No platform data\n"); + r = -EINVAL; + goto err_pdata; + } + + if (pdata->request_resources == NULL) { + dev_err(&client->dev, "request_resources() missing\n"); + r = -EINVAL; + goto err_pdata; + } + + r = pdata->request_resources(client); + if (r) { + dev_err(&client->dev, "Cannot get platform resources\n"); + goto err_pdata; + } + + phy->gpio_en = pdata->get_gpio(NFC_GPIO_ENABLE); + phy->gpio_fw = pdata->get_gpio(NFC_GPIO_FW_RESET); + phy->gpio_irq = pdata->get_gpio(NFC_GPIO_IRQ); + + pn544_hci_i2c_platform_init(phy); + + r = request_threaded_irq(client->irq, NULL, pn544_hci_i2c_irq_thread_fn, + IRQF_TRIGGER_RISING | IRQF_ONESHOT, + PN544_HCI_I2C_DRIVER_NAME, phy); + if (r < 0) { + dev_err(&client->dev, "Unable to register IRQ handler\n"); + goto err_rti; + } + + r = pn544_hci_probe(phy, &i2c_phy_ops, LLC_SHDLC_NAME, + PN544_I2C_FRAME_HEADROOM, PN544_I2C_FRAME_TAILROOM, + PN544_HCI_I2C_LLC_MAX_PAYLOAD, &phy->hdev); + if (r < 0) + goto err_hci; + + return 0; + +err_hci: + free_irq(client->irq, phy); + +err_rti: + if (pdata->free_resources != NULL) + pdata->free_resources(); + +err_pdata: + kfree(phy); + +err_phy_alloc: + return r; +} + +static __devexit int pn544_hci_i2c_remove(struct i2c_client *client) +{ + struct pn544_i2c_phy *phy = i2c_get_clientdata(client); + struct pn544_nfc_platform_data *pdata = client->dev.platform_data; + + dev_dbg(&client->dev, "%s\n", __func__); + + pn544_hci_remove(phy->hdev); + + if (phy->powered) + pn544_hci_i2c_disable(phy); + + free_irq(client->irq, phy); + if (pdata->free_resources) + pdata->free_resources(); + + kfree(phy); + + return 0; +} + +static struct i2c_driver pn544_hci_i2c_driver = { + .driver = { + .name = PN544_HCI_I2C_DRIVER_NAME, + }, + .probe = pn544_hci_i2c_probe, + .id_table = pn544_hci_i2c_id_table, + .remove = __devexit_p(pn544_hci_i2c_remove), +}; + +static int __init pn544_hci_i2c_init(void) +{ + int r; + + pr_debug(DRIVER_DESC ": %s\n", __func__); + + r = i2c_add_driver(&pn544_hci_i2c_driver); + if (r) { + pr_err(PN544_HCI_I2C_DRIVER_NAME + ": driver registration failed\n"); + return r; + } + + return 0; +} + +static void __exit pn544_hci_i2c_exit(void) +{ + i2c_del_driver(&pn544_hci_i2c_driver); +} + +module_init(pn544_hci_i2c_init); +module_exit(pn544_hci_i2c_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION(DRIVER_DESC); |