diff options
Diffstat (limited to 'drivers/mfd/rave-sp.c')
| -rw-r--r-- | drivers/mfd/rave-sp.c | 710 |
1 files changed, 710 insertions, 0 deletions
diff --git a/drivers/mfd/rave-sp.c b/drivers/mfd/rave-sp.c new file mode 100644 index 000000000000..5c858e784a89 --- /dev/null +++ b/drivers/mfd/rave-sp.c @@ -0,0 +1,710 @@ +// SPDX-License-Identifier: GPL-2.0+ + +/* + * Multifunction core driver for Zodiac Inflight Innovations RAVE + * Supervisory Processor(SP) MCU that is connected via dedicated UART + * port + * + * Copyright (C) 2017 Zodiac Inflight Innovations + */ + +#include <linux/atomic.h> +#include <linux/crc-ccitt.h> +#include <linux/delay.h> +#include <linux/export.h> +#include <linux/init.h> +#include <linux/slab.h> +#include <linux/kernel.h> +#include <linux/mfd/rave-sp.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/sched.h> +#include <linux/serdev.h> +#include <asm/unaligned.h> + +/* + * UART protocol using following entities: + * - message to MCU => ACK response + * - event from MCU => event ACK + * + * Frame structure: + * <STX> <DATA> <CHECKSUM> <ETX> + * Where: + * - STX - is start of transmission character + * - ETX - end of transmission + * - DATA - payload + * - CHECKSUM - checksum calculated on <DATA> + * + * If <DATA> or <CHECKSUM> contain one of control characters, then it is + * escaped using <DLE> control code. Added <DLE> does not participate in + * checksum calculation. + */ +#define RAVE_SP_STX 0x02 +#define RAVE_SP_ETX 0x03 +#define RAVE_SP_DLE 0x10 + +#define RAVE_SP_MAX_DATA_SIZE 64 +#define RAVE_SP_CHECKSUM_SIZE 2 /* Worst case scenario on RDU2 */ +/* + * We don't store STX, ETX and unescaped bytes, so Rx is only + * DATA + CSUM + */ +#define RAVE_SP_RX_BUFFER_SIZE \ + (RAVE_SP_MAX_DATA_SIZE + RAVE_SP_CHECKSUM_SIZE) + +#define RAVE_SP_STX_ETX_SIZE 2 +/* + * For Tx we have to have space for everything, STX, EXT and + * potentially stuffed DATA + CSUM data + csum + */ +#define RAVE_SP_TX_BUFFER_SIZE \ + (RAVE_SP_STX_ETX_SIZE + 2 * RAVE_SP_RX_BUFFER_SIZE) + +#define RAVE_SP_BOOT_SOURCE_GET 0 +#define RAVE_SP_BOOT_SOURCE_SET 1 + +#define RAVE_SP_RDU2_BOARD_TYPE_RMB 0 +#define RAVE_SP_RDU2_BOARD_TYPE_DEB 1 + +#define RAVE_SP_BOOT_SOURCE_SD 0 +#define RAVE_SP_BOOT_SOURCE_EMMC 1 +#define RAVE_SP_BOOT_SOURCE_NOR 2 + +/** + * enum rave_sp_deframer_state - Possible state for de-framer + * + * @RAVE_SP_EXPECT_SOF: Scanning input for start-of-frame marker + * @RAVE_SP_EXPECT_DATA: Got start of frame marker, collecting frame + * @RAVE_SP_EXPECT_ESCAPED_DATA: Got escape character, collecting escaped byte + */ +enum rave_sp_deframer_state { + RAVE_SP_EXPECT_SOF, + RAVE_SP_EXPECT_DATA, + RAVE_SP_EXPECT_ESCAPED_DATA, +}; + +/** + * struct rave_sp_deframer - Device protocol deframer + * + * @state: Current state of the deframer + * @data: Buffer used to collect deframed data + * @length: Number of bytes de-framed so far + */ +struct rave_sp_deframer { + enum rave_sp_deframer_state state; + unsigned char data[RAVE_SP_RX_BUFFER_SIZE]; + size_t length; +}; + +/** + * struct rave_sp_reply - Reply as per RAVE device protocol + * + * @length: Expected reply length + * @data: Buffer to store reply payload in + * @code: Expected reply code + * @ackid: Expected reply ACK ID + * @completion: Successful reply reception completion + */ +struct rave_sp_reply { + size_t length; + void *data; + u8 code; + u8 ackid; + struct completion received; +}; + +/** + * struct rave_sp_checksum - Variant specific checksum implementation details + * + * @length: Caculated checksum length + * @subroutine: Utilized checksum algorithm implementation + */ +struct rave_sp_checksum { + size_t length; + void (*subroutine)(const u8 *, size_t, u8 *); +}; + +/** + * struct rave_sp_variant_cmds - Variant specific command routines + * + * @translate: Generic to variant specific command mapping routine + * + */ +struct rave_sp_variant_cmds { + int (*translate)(enum rave_sp_command); +}; + +/** + * struct rave_sp_variant - RAVE supervisory processor core variant + * + * @checksum: Variant specific checksum implementation + * @cmd: Variant specific command pointer table + * + */ +struct rave_sp_variant { + const struct rave_sp_checksum *checksum; + struct rave_sp_variant_cmds cmd; +}; + +/** + * struct rave_sp - RAVE supervisory processor core + * + * @serdev: Pointer to underlying serdev + * @deframer: Stored state of the protocol deframer + * @ackid: ACK ID used in last reply sent to the device + * @bus_lock: Lock to serialize access to the device + * @reply_lock: Lock protecting @reply + * @reply: Pointer to memory to store reply payload + * + * @variant: Device variant specific information + * @event_notifier_list: Input event notification chain + * + */ +struct rave_sp { + struct serdev_device *serdev; + struct rave_sp_deframer deframer; + atomic_t ackid; + struct mutex bus_lock; + struct mutex reply_lock; + struct rave_sp_reply *reply; + + const struct rave_sp_variant *variant; + struct blocking_notifier_head event_notifier_list; +}; + +static bool rave_sp_id_is_event(u8 code) +{ + return (code & 0xF0) == RAVE_SP_EVNT_BASE; +} + +static void rave_sp_unregister_event_notifier(struct device *dev, void *res) +{ + struct rave_sp *sp = dev_get_drvdata(dev->parent); + struct notifier_block *nb = *(struct notifier_block **)res; + struct blocking_notifier_head *bnh = &sp->event_notifier_list; + + WARN_ON(blocking_notifier_chain_unregister(bnh, nb)); +} + +int devm_rave_sp_register_event_notifier(struct device *dev, + struct notifier_block *nb) +{ + struct rave_sp *sp = dev_get_drvdata(dev->parent); + struct notifier_block **rcnb; + int ret; + + rcnb = devres_alloc(rave_sp_unregister_event_notifier, + sizeof(*rcnb), GFP_KERNEL); + if (!rcnb) + return -ENOMEM; + + ret = blocking_notifier_chain_register(&sp->event_notifier_list, nb); + if (!ret) { + *rcnb = nb; + devres_add(dev, rcnb); + } else { + devres_free(rcnb); + } + + return ret; +} +EXPORT_SYMBOL_GPL(devm_rave_sp_register_event_notifier); + +static void csum_8b2c(const u8 *buf, size_t size, u8 *crc) +{ + *crc = *buf++; + size--; + + while (size--) + *crc += *buf++; + + *crc = 1 + ~(*crc); +} + +static void csum_ccitt(const u8 *buf, size_t size, u8 *crc) +{ + const u16 calculated = crc_ccitt_false(0xffff, buf, size); + + /* + * While the rest of the wire protocol is little-endian, + * CCITT-16 CRC in RDU2 device is sent out in big-endian order. + */ + put_unaligned_be16(calculated, crc); +} + +static void *stuff(unsigned char *dest, const unsigned char *src, size_t n) +{ + while (n--) { + const unsigned char byte = *src++; + + switch (byte) { + case RAVE_SP_STX: + case RAVE_SP_ETX: + case RAVE_SP_DLE: + *dest++ = RAVE_SP_DLE; + /* FALLTHROUGH */ + default: + *dest++ = byte; + } + } + + return dest; +} + +static int rave_sp_write(struct rave_sp *sp, const u8 *data, u8 data_size) +{ + const size_t checksum_length = sp->variant->checksum->length; + unsigned char frame[RAVE_SP_TX_BUFFER_SIZE]; + unsigned char crc[RAVE_SP_CHECKSUM_SIZE]; + unsigned char *dest = frame; + size_t length; + + if (WARN_ON(checksum_length > sizeof(crc))) + return -ENOMEM; + + if (WARN_ON(data_size > sizeof(frame))) + return -ENOMEM; + + sp->variant->checksum->subroutine(data, data_size, crc); + + *dest++ = RAVE_SP_STX; + dest = stuff(dest, data, data_size); + dest = stuff(dest, crc, checksum_length); + *dest++ = RAVE_SP_ETX; + + length = dest - frame; + + print_hex_dump(KERN_DEBUG, "rave-sp tx: ", DUMP_PREFIX_NONE, + 16, 1, frame, length, false); + + return serdev_device_write(sp->serdev, frame, length, HZ); +} + +static u8 rave_sp_reply_code(u8 command) +{ + /* + * There isn't a single rule that describes command code -> + * ACK code transformation, but, going through various + * versions of ICDs, there appear to be three distinct groups + * that can be described by simple transformation. + */ + switch (command) { + case 0xA0 ... 0xBE: + /* + * Commands implemented by firmware found in RDU1 and + * older devices all seem to obey the following rule + */ + return command + 0x20; + case 0xE0 ... 0xEF: + /* + * Events emitted by all versions of the firmare use + * least significant bit to get an ACK code + */ + return command | 0x01; + default: + /* + * Commands implemented by firmware found in RDU2 are + * similar to "old" commands, but they use slightly + * different offset + */ + return command + 0x40; + } +} + +int rave_sp_exec(struct rave_sp *sp, + void *__data, size_t data_size, + void *reply_data, size_t reply_data_size) +{ + struct rave_sp_reply reply = { + .data = reply_data, + .length = reply_data_size, + .received = COMPLETION_INITIALIZER_ONSTACK(reply.received), + }; + unsigned char *data = __data; + int command, ret = 0; + u8 ackid; + + command = sp->variant->cmd.translate(data[0]); + if (command < 0) + return command; + + ackid = atomic_inc_return(&sp->ackid); + reply.ackid = ackid; + reply.code = rave_sp_reply_code((u8)command), + + mutex_lock(&sp->bus_lock); + + mutex_lock(&sp->reply_lock); + sp->reply = &reply; + mutex_unlock(&sp->reply_lock); + + data[0] = command; + data[1] = ackid; + + rave_sp_write(sp, data, data_size); + + if (!wait_for_completion_timeout(&reply.received, HZ)) { + dev_err(&sp->serdev->dev, "Command timeout\n"); + ret = -ETIMEDOUT; + + mutex_lock(&sp->reply_lock); + sp->reply = NULL; + mutex_unlock(&sp->reply_lock); + } + + mutex_unlock(&sp->bus_lock); + return ret; +} +EXPORT_SYMBOL_GPL(rave_sp_exec); + +static void rave_sp_receive_event(struct rave_sp *sp, + const unsigned char *data, size_t length) +{ + u8 cmd[] = { + [0] = rave_sp_reply_code(data[0]), + [1] = data[1], + }; + + rave_sp_write(sp, cmd, sizeof(cmd)); + + blocking_notifier_call_chain(&sp->event_notifier_list, + rave_sp_action_pack(data[0], data[2]), + NULL); +} + +static void rave_sp_receive_reply(struct rave_sp *sp, + const unsigned char *data, size_t length) +{ + struct device *dev = &sp->serdev->dev; + struct rave_sp_reply *reply; + const size_t payload_length = length - 2; + + mutex_lock(&sp->reply_lock); + reply = sp->reply; + + if (reply) { + if (reply->code == data[0] && reply->ackid == data[1] && + payload_length >= reply->length) { + /* + * We are relying on memcpy(dst, src, 0) to be a no-op + * when handling commands that have a no-payload reply + */ + memcpy(reply->data, &data[2], reply->length); + complete(&reply->received); + sp->reply = NULL; + } else { + dev_err(dev, "Ignoring incorrect reply\n"); + dev_dbg(dev, "Code: expected = 0x%08x received = 0x%08x\n", + reply->code, data[0]); + dev_dbg(dev, "ACK ID: expected = 0x%08x received = 0x%08x\n", + reply->ackid, data[1]); + dev_dbg(dev, "Length: expected = %zu received = %zu\n", + reply->length, payload_length); + } + } + + mutex_unlock(&sp->reply_lock); +} + +static void rave_sp_receive_frame(struct rave_sp *sp, + const unsigned char *data, + size_t length) +{ + const size_t checksum_length = sp->variant->checksum->length; + const size_t payload_length = length - checksum_length; + const u8 *crc_reported = &data[payload_length]; + struct device *dev = &sp->serdev->dev; + u8 crc_calculated[checksum_length]; + + print_hex_dump(KERN_DEBUG, "rave-sp rx: ", DUMP_PREFIX_NONE, + 16, 1, data, length, false); + + if (unlikely(length <= checksum_length)) { + dev_warn(dev, "Dropping short frame\n"); + return; + } + + sp->variant->checksum->subroutine(data, payload_length, + crc_calculated); + + if (memcmp(crc_calculated, crc_reported, checksum_length)) { + dev_warn(dev, "Dropping bad frame\n"); + return; + } + + if (rave_sp_id_is_event(data[0])) + rave_sp_receive_event(sp, data, length); + else + rave_sp_receive_reply(sp, data, length); +} + +static int rave_sp_receive_buf(struct serdev_device *serdev, + const unsigned char *buf, size_t size) +{ + struct device *dev = &serdev->dev; + struct rave_sp *sp = dev_get_drvdata(dev); + struct rave_sp_deframer *deframer = &sp->deframer; + const unsigned char *src = buf; + const unsigned char *end = buf + size; + + while (src < end) { + const unsigned char byte = *src++; + + switch (deframer->state) { + case RAVE_SP_EXPECT_SOF: + if (byte == RAVE_SP_STX) + deframer->state = RAVE_SP_EXPECT_DATA; + break; + + case RAVE_SP_EXPECT_DATA: + /* + * Treat special byte values first + */ + switch (byte) { + case RAVE_SP_ETX: + rave_sp_receive_frame(sp, + deframer->data, + deframer->length); + /* + * Once we extracted a complete frame + * out of a stream, we call it done + * and proceed to bailing out while + * resetting the framer to initial + * state, regardless if we've consumed + * all of the stream or not. + */ + goto reset_framer; + case RAVE_SP_STX: + dev_warn(dev, "Bad frame: STX before ETX\n"); + /* + * If we encounter second "start of + * the frame" marker before seeing + * corresponding "end of frame", we + * reset the framer and ignore both: + * frame started by first SOF and + * frame started by current SOF. + * + * NOTE: The above means that only the + * frame started by third SOF, sent + * after this one will have a chance + * to get throught. + */ + goto reset_framer; + case RAVE_SP_DLE: + deframer->state = RAVE_SP_EXPECT_ESCAPED_DATA; + /* + * If we encounter escape sequence we + * need to skip it and collect the + * byte that follows. We do it by + * forcing the next iteration of the + * encompassing while loop. + */ + continue; + } + /* + * For the rest of the bytes, that are not + * speical snoflakes, we do the same thing + * that we do to escaped data - collect it in + * deframer buffer + */ + + /* FALLTHROUGH */ + + case RAVE_SP_EXPECT_ESCAPED_DATA: + deframer->data[deframer->length++] = byte; + + if (deframer->length == sizeof(deframer->data)) { + dev_warn(dev, "Bad frame: Too long\n"); + /* + * If the amount of data we've + * accumulated for current frame so + * far starts to exceed the capacity + * of deframer's buffer, there's + * nothing else we can do but to + * discard that data and start + * assemblying a new frame again + */ + goto reset_framer; + } + + /* + * We've extracted out special byte, now we + * can go back to regular data collecting + */ + deframer->state = RAVE_SP_EXPECT_DATA; + break; + } + } + + /* + * The only way to get out of the above loop and end up here + * is throught consuming all of the supplied data, so here we + * report that we processed it all. + */ + return size; + +reset_framer: + /* + * NOTE: A number of codepaths that will drop us here will do + * so before consuming all 'size' bytes of the data passed by + * serdev layer. We rely on the fact that serdev layer will + * re-execute this handler with the remainder of the Rx bytes + * once we report actual number of bytes that we processed. + */ + deframer->state = RAVE_SP_EXPECT_SOF; + deframer->length = 0; + + return src - buf; +} + +static int rave_sp_rdu1_cmd_translate(enum rave_sp_command command) +{ + if (command >= RAVE_SP_CMD_STATUS && + command <= RAVE_SP_CMD_CONTROL_EVENTS) + return command; + + return -EINVAL; +} + +static int rave_sp_rdu2_cmd_translate(enum rave_sp_command command) +{ + if (command >= RAVE_SP_CMD_GET_FIRMWARE_VERSION && + command <= RAVE_SP_CMD_GET_GPIO_STATE) + return command; + + if (command == RAVE_SP_CMD_REQ_COPPER_REV) { + /* + * As per RDU2 ICD 3.4.47 CMD_GET_COPPER_REV code is + * different from that for RDU1 and it is set to 0x28. + */ + return 0x28; + } + + return rave_sp_rdu1_cmd_translate(command); +} + +static int rave_sp_default_cmd_translate(enum rave_sp_command command) +{ + /* + * All of the following command codes were taken from "Table : + * Communications Protocol Message Types" in section 3.3 + * "MESSAGE TYPES" of Rave PIC24 ICD. + */ + switch (command) { + case RAVE_SP_CMD_GET_FIRMWARE_VERSION: + return 0x11; + case RAVE_SP_CMD_GET_BOOTLOADER_VERSION: + return 0x12; + case RAVE_SP_CMD_BOOT_SOURCE: + return 0x14; + case RAVE_SP_CMD_SW_WDT: + return 0x1C; + case RAVE_SP_CMD_RESET: + return 0x1E; + case RAVE_SP_CMD_RESET_REASON: + return 0x1F; + default: + return -EINVAL; + } +} + +static const struct rave_sp_checksum rave_sp_checksum_8b2c = { + .length = 1, + .subroutine = csum_8b2c, +}; + +static const struct rave_sp_checksum rave_sp_checksum_ccitt = { + .length = 2, + .subroutine = csum_ccitt, +}; + +static const struct rave_sp_variant rave_sp_legacy = { + .checksum = &rave_sp_checksum_8b2c, + .cmd = { + .translate = rave_sp_default_cmd_translate, + }, +}; + +static const struct rave_sp_variant rave_sp_rdu1 = { + .checksum = &rave_sp_checksum_8b2c, + .cmd = { + .translate = rave_sp_rdu1_cmd_translate, + }, +}; + +static const struct rave_sp_variant rave_sp_rdu2 = { + .checksum = &rave_sp_checksum_ccitt, + .cmd = { + .translate = rave_sp_rdu2_cmd_translate, + }, +}; + +static const struct of_device_id rave_sp_dt_ids[] = { + { .compatible = "zii,rave-sp-niu", .data = &rave_sp_legacy }, + { .compatible = "zii,rave-sp-mezz", .data = &rave_sp_legacy }, + { .compatible = "zii,rave-sp-esb", .data = &rave_sp_legacy }, + { .compatible = "zii,rave-sp-rdu1", .data = &rave_sp_rdu1 }, + { .compatible = "zii,rave-sp-rdu2", .data = &rave_sp_rdu2 }, + { /* sentinel */ } +}; + +static const struct serdev_device_ops rave_sp_serdev_device_ops = { + .receive_buf = rave_sp_receive_buf, + .write_wakeup = serdev_device_write_wakeup, +}; + +static int rave_sp_probe(struct serdev_device *serdev) +{ + struct device *dev = &serdev->dev; + struct rave_sp *sp; + u32 baud; + int ret; + + if (of_property_read_u32(dev->of_node, "current-speed", &baud)) { + dev_err(dev, + "'current-speed' is not specified in device node\n"); + return -EINVAL; + } + + sp = devm_kzalloc(dev, sizeof(*sp), GFP_KERNEL); + if (!sp) + return -ENOMEM; + + sp->serdev = serdev; + dev_set_drvdata(dev, sp); + + sp->variant = of_device_get_match_data(dev); + if (!sp->variant) + return -ENODEV; + + mutex_init(&sp->bus_lock); + mutex_init(&sp->reply_lock); + BLOCKING_INIT_NOTIFIER_HEAD(&sp->event_notifier_list); + + serdev_device_set_client_ops(serdev, &rave_sp_serdev_device_ops); + ret = devm_serdev_device_open(dev, serdev); + if (ret) + return ret; + + serdev_device_set_baudrate(serdev, baud); + + return devm_of_platform_populate(dev); +} + +MODULE_DEVICE_TABLE(of, rave_sp_dt_ids); + +static struct serdev_device_driver rave_sp_drv = { + .probe = rave_sp_probe, + .driver = { + .name = "rave-sp", + .of_match_table = rave_sp_dt_ids, + }, +}; +module_serdev_device_driver(rave_sp_drv); + +MODULE_LICENSE("GPL"); +MODULE_AUTHOR("Andrey Vostrikov <andrey.vostrikov@cogentembedded.com>"); +MODULE_AUTHOR("Nikita Yushchenko <nikita.yoush@cogentembedded.com>"); +MODULE_AUTHOR("Andrey Smirnov <andrew.smirnov@gmail.com>"); +MODULE_DESCRIPTION("RAVE SP core driver"); |