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-rw-r--r--drivers/mfd/rave-sp.c710
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");