| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Edward A. James | 3064 | 100.00% | 6 | 100.00% |
| Total | 3064 | 6 |
// SPDX-License-Identifier: GPL-2.0+ /* * FSI-attached I2C master algorithm * * Copyright 2018 IBM Corporation * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include <linux/bitfield.h> #include <linux/bitops.h> #include <linux/delay.h> #include <linux/device.h> #include <linux/errno.h> #include <linux/fsi.h> #include <linux/i2c.h> #include <linux/jiffies.h> #include <linux/kernel.h> #include <linux/list.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/of.h> #include <linux/slab.h> #define FSI_ENGID_I2C 0x7 #define I2C_DEFAULT_CLK_DIV 6 /* i2c registers */ #define I2C_FSI_FIFO 0x00 #define I2C_FSI_CMD 0x04 #define I2C_FSI_MODE 0x08 #define I2C_FSI_WATER_MARK 0x0C #define I2C_FSI_INT_MASK 0x10 #define I2C_FSI_INT_COND 0x14 #define I2C_FSI_OR_INT_MASK 0x14 #define I2C_FSI_INTS 0x18 #define I2C_FSI_AND_INT_MASK 0x18 #define I2C_FSI_STAT 0x1C #define I2C_FSI_RESET_I2C 0x1C #define I2C_FSI_ESTAT 0x20 #define I2C_FSI_RESET_ERR 0x20 #define I2C_FSI_RESID_LEN 0x24 #define I2C_FSI_SET_SCL 0x24 #define I2C_FSI_PORT_BUSY 0x28 #define I2C_FSI_RESET_SCL 0x2C #define I2C_FSI_SET_SDA 0x30 #define I2C_FSI_RESET_SDA 0x34 /* cmd register */ #define I2C_CMD_WITH_START BIT(31) #define I2C_CMD_WITH_ADDR BIT(30) #define I2C_CMD_RD_CONT BIT(29) #define I2C_CMD_WITH_STOP BIT(28) #define I2C_CMD_FORCELAUNCH BIT(27) #define I2C_CMD_ADDR GENMASK(23, 17) #define I2C_CMD_READ BIT(16) #define I2C_CMD_LEN GENMASK(15, 0) /* mode register */ #define I2C_MODE_CLKDIV GENMASK(31, 16) #define I2C_MODE_PORT GENMASK(15, 10) #define I2C_MODE_ENHANCED BIT(3) #define I2C_MODE_DIAG BIT(2) #define I2C_MODE_PACE_ALLOW BIT(1) #define I2C_MODE_WRAP BIT(0) /* watermark register */ #define I2C_WATERMARK_HI GENMASK(15, 12) #define I2C_WATERMARK_LO GENMASK(7, 4) #define I2C_FIFO_HI_LVL 4 #define I2C_FIFO_LO_LVL 4 /* interrupt register */ #define I2C_INT_INV_CMD BIT(15) #define I2C_INT_PARITY BIT(14) #define I2C_INT_BE_OVERRUN BIT(13) #define I2C_INT_BE_ACCESS BIT(12) #define I2C_INT_LOST_ARB BIT(11) #define I2C_INT_NACK BIT(10) #define I2C_INT_DAT_REQ BIT(9) #define I2C_INT_CMD_COMP BIT(8) #define I2C_INT_STOP_ERR BIT(7) #define I2C_INT_BUSY BIT(6) #define I2C_INT_IDLE BIT(5) /* status register */ #define I2C_STAT_INV_CMD BIT(31) #define I2C_STAT_PARITY BIT(30) #define I2C_STAT_BE_OVERRUN BIT(29) #define I2C_STAT_BE_ACCESS BIT(28) #define I2C_STAT_LOST_ARB BIT(27) #define I2C_STAT_NACK BIT(26) #define I2C_STAT_DAT_REQ BIT(25) #define I2C_STAT_CMD_COMP BIT(24) #define I2C_STAT_STOP_ERR BIT(23) #define I2C_STAT_MAX_PORT GENMASK(19, 16) #define I2C_STAT_ANY_INT BIT(15) #define I2C_STAT_SCL_IN BIT(11) #define I2C_STAT_SDA_IN BIT(10) #define I2C_STAT_PORT_BUSY BIT(9) #define I2C_STAT_SELF_BUSY BIT(8) #define I2C_STAT_FIFO_COUNT GENMASK(7, 0) #define I2C_STAT_ERR (I2C_STAT_INV_CMD | \ I2C_STAT_PARITY | \ I2C_STAT_BE_OVERRUN | \ I2C_STAT_BE_ACCESS | \ I2C_STAT_LOST_ARB | \ I2C_STAT_NACK | \ I2C_STAT_STOP_ERR) #define I2C_STAT_ANY_RESP (I2C_STAT_ERR | \ I2C_STAT_DAT_REQ | \ I2C_STAT_CMD_COMP) /* extended status register */ #define I2C_ESTAT_FIFO_SZ GENMASK(31, 24) #define I2C_ESTAT_SCL_IN_SY BIT(15) #define I2C_ESTAT_SDA_IN_SY BIT(14) #define I2C_ESTAT_S_SCL BIT(13) #define I2C_ESTAT_S_SDA BIT(12) #define I2C_ESTAT_M_SCL BIT(11) #define I2C_ESTAT_M_SDA BIT(10) #define I2C_ESTAT_HI_WATER BIT(9) #define I2C_ESTAT_LO_WATER BIT(8) #define I2C_ESTAT_PORT_BUSY BIT(7) #define I2C_ESTAT_SELF_BUSY BIT(6) #define I2C_ESTAT_VERSION GENMASK(4, 0) /* port busy register */ #define I2C_PORT_BUSY_RESET BIT(31) /* wait for command complete or data request */ #define I2C_CMD_SLEEP_MAX_US 500 #define I2C_CMD_SLEEP_MIN_US 50 /* wait after reset; choose time from legacy driver */ #define I2C_RESET_SLEEP_MAX_US 2000 #define I2C_RESET_SLEEP_MIN_US 1000 /* choose timeout length from legacy driver; it's well tested */ #define I2C_ABORT_TIMEOUT msecs_to_jiffies(100) struct fsi_i2c_master { struct fsi_device *fsi; u8 fifo_size; struct list_head ports; struct mutex lock; }; struct fsi_i2c_port { struct list_head list; struct i2c_adapter adapter; struct fsi_i2c_master *master; u16 port; u16 xfrd; }; static int fsi_i2c_read_reg(struct fsi_device *fsi, unsigned int reg, u32 *data) { int rc; __be32 data_be; rc = fsi_device_read(fsi, reg, &data_be, sizeof(data_be)); if (rc) return rc; *data = be32_to_cpu(data_be); return 0; } static int fsi_i2c_write_reg(struct fsi_device *fsi, unsigned int reg, u32 *data) { __be32 data_be = cpu_to_be32p(data); return fsi_device_write(fsi, reg, &data_be, sizeof(data_be)); } static int fsi_i2c_dev_init(struct fsi_i2c_master *i2c) { int rc; u32 mode = I2C_MODE_ENHANCED, extended_status, watermark; u32 interrupt = 0; /* since we use polling, disable interrupts */ rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_INT_MASK, &interrupt); if (rc) return rc; mode |= FIELD_PREP(I2C_MODE_CLKDIV, I2C_DEFAULT_CLK_DIV); rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); if (rc) return rc; rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_ESTAT, &extended_status); if (rc) return rc; i2c->fifo_size = FIELD_GET(I2C_ESTAT_FIFO_SZ, extended_status); watermark = FIELD_PREP(I2C_WATERMARK_HI, i2c->fifo_size - I2C_FIFO_HI_LVL); watermark |= FIELD_PREP(I2C_WATERMARK_LO, I2C_FIFO_LO_LVL); return fsi_i2c_write_reg(i2c->fsi, I2C_FSI_WATER_MARK, &watermark); } static int fsi_i2c_set_port(struct fsi_i2c_port *port) { int rc; struct fsi_device *fsi = port->master->fsi; u32 mode, dummy = 0; rc = fsi_i2c_read_reg(fsi, I2C_FSI_MODE, &mode); if (rc) return rc; if (FIELD_GET(I2C_MODE_PORT, mode) == port->port) return 0; mode = (mode & ~I2C_MODE_PORT) | FIELD_PREP(I2C_MODE_PORT, port->port); rc = fsi_i2c_write_reg(fsi, I2C_FSI_MODE, &mode); if (rc) return rc; /* reset engine when port is changed */ return fsi_i2c_write_reg(fsi, I2C_FSI_RESET_ERR, &dummy); } static int fsi_i2c_start(struct fsi_i2c_port *port, struct i2c_msg *msg, bool stop) { struct fsi_i2c_master *i2c = port->master; u32 cmd = I2C_CMD_WITH_START | I2C_CMD_WITH_ADDR; port->xfrd = 0; if (msg->flags & I2C_M_RD) cmd |= I2C_CMD_READ; if (stop || msg->flags & I2C_M_STOP) cmd |= I2C_CMD_WITH_STOP; cmd |= FIELD_PREP(I2C_CMD_ADDR, msg->addr); cmd |= FIELD_PREP(I2C_CMD_LEN, msg->len); return fsi_i2c_write_reg(i2c->fsi, I2C_FSI_CMD, &cmd); } static int fsi_i2c_get_op_bytes(int op_bytes) { /* fsi is limited to max 4 byte aligned ops */ if (op_bytes > 4) return 4; else if (op_bytes == 3) return 2; return op_bytes; } static int fsi_i2c_write_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg, u8 fifo_count) { int write; int rc; struct fsi_i2c_master *i2c = port->master; int bytes_to_write = i2c->fifo_size - fifo_count; int bytes_remaining = msg->len - port->xfrd; bytes_to_write = min(bytes_to_write, bytes_remaining); while (bytes_to_write) { write = fsi_i2c_get_op_bytes(bytes_to_write); rc = fsi_device_write(i2c->fsi, I2C_FSI_FIFO, &msg->buf[port->xfrd], write); if (rc) return rc; port->xfrd += write; bytes_to_write -= write; } return 0; } static int fsi_i2c_read_fifo(struct fsi_i2c_port *port, struct i2c_msg *msg, u8 fifo_count) { int read; int rc; struct fsi_i2c_master *i2c = port->master; int bytes_to_read; int xfr_remaining = msg->len - port->xfrd; u32 dummy; bytes_to_read = min_t(int, fifo_count, xfr_remaining); while (bytes_to_read) { read = fsi_i2c_get_op_bytes(bytes_to_read); if (xfr_remaining) { rc = fsi_device_read(i2c->fsi, I2C_FSI_FIFO, &msg->buf[port->xfrd], read); if (rc) return rc; port->xfrd += read; xfr_remaining -= read; } else { /* no more buffer but data in fifo, need to clear it */ rc = fsi_device_read(i2c->fsi, I2C_FSI_FIFO, &dummy, read); if (rc) return rc; } bytes_to_read -= read; } return 0; } static int fsi_i2c_get_scl(struct i2c_adapter *adap) { u32 stat = 0; struct fsi_i2c_port *port = adap->algo_data; struct fsi_i2c_master *i2c = port->master; fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat); return !!(stat & I2C_STAT_SCL_IN); } static void fsi_i2c_set_scl(struct i2c_adapter *adap, int val) { u32 dummy = 0; struct fsi_i2c_port *port = adap->algo_data; struct fsi_i2c_master *i2c = port->master; if (val) fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SCL, &dummy); else fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SCL, &dummy); } static int fsi_i2c_get_sda(struct i2c_adapter *adap) { u32 stat = 0; struct fsi_i2c_port *port = adap->algo_data; struct fsi_i2c_master *i2c = port->master; fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat); return !!(stat & I2C_STAT_SDA_IN); } static void fsi_i2c_set_sda(struct i2c_adapter *adap, int val) { u32 dummy = 0; struct fsi_i2c_port *port = adap->algo_data; struct fsi_i2c_master *i2c = port->master; if (val) fsi_i2c_write_reg(i2c->fsi, I2C_FSI_SET_SDA, &dummy); else fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_SDA, &dummy); } static void fsi_i2c_prepare_recovery(struct i2c_adapter *adap) { int rc; u32 mode; struct fsi_i2c_port *port = adap->algo_data; struct fsi_i2c_master *i2c = port->master; rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode); if (rc) return; mode |= I2C_MODE_DIAG; fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); } static void fsi_i2c_unprepare_recovery(struct i2c_adapter *adap) { int rc; u32 mode; struct fsi_i2c_port *port = adap->algo_data; struct fsi_i2c_master *i2c = port->master; rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode); if (rc) return; mode &= ~I2C_MODE_DIAG; fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); } static int fsi_i2c_reset_bus(struct fsi_i2c_master *i2c, struct fsi_i2c_port *port) { int rc; u32 stat, dummy = 0; /* force bus reset, ignore errors */ i2c_recover_bus(&port->adapter); /* reset errors */ rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_ERR, &dummy); if (rc) return rc; /* wait for command complete */ usleep_range(I2C_RESET_SLEEP_MIN_US, I2C_RESET_SLEEP_MAX_US); rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_STAT, &stat); if (rc) return rc; if (stat & I2C_STAT_CMD_COMP) return 0; /* failed to get command complete; reset engine again */ rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_I2C, &dummy); if (rc) return rc; /* re-init engine again */ return fsi_i2c_dev_init(i2c); } static int fsi_i2c_reset_engine(struct fsi_i2c_master *i2c, u16 port) { int rc; u32 mode, dummy = 0; /* reset engine */ rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_RESET_I2C, &dummy); if (rc) return rc; /* re-init engine */ rc = fsi_i2c_dev_init(i2c); if (rc) return rc; rc = fsi_i2c_read_reg(i2c->fsi, I2C_FSI_MODE, &mode); if (rc) return rc; /* set port; default after reset is 0 */ if (port) { mode &= ~I2C_MODE_PORT; mode |= FIELD_PREP(I2C_MODE_PORT, port); rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_MODE, &mode); if (rc) return rc; } /* reset busy register; hw workaround */ dummy = I2C_PORT_BUSY_RESET; rc = fsi_i2c_write_reg(i2c->fsi, I2C_FSI_PORT_BUSY, &dummy); if (rc) return rc; return 0; } static int fsi_i2c_abort(struct fsi_i2c_port *port, u32 status) { int rc; unsigned long start; u32 cmd = I2C_CMD_WITH_STOP; u32 stat; struct fsi_i2c_master *i2c = port->master; struct fsi_device *fsi = i2c->fsi; rc = fsi_i2c_reset_engine(i2c, port->port); if (rc) return rc; rc = fsi_i2c_read_reg(fsi, I2C_FSI_STAT, &stat); if (rc) return rc; /* if sda is low, peform full bus reset */ if (!(stat & I2C_STAT_SDA_IN)) { rc = fsi_i2c_reset_bus(i2c, port); if (rc) return rc; } /* skip final stop command for these errors */ if (status & (I2C_STAT_PARITY | I2C_STAT_LOST_ARB | I2C_STAT_STOP_ERR)) return 0; /* write stop command */ rc = fsi_i2c_write_reg(fsi, I2C_FSI_CMD, &cmd); if (rc) return rc; /* wait until we see command complete in the master */ start = jiffies; do { rc = fsi_i2c_read_reg(fsi, I2C_FSI_STAT, &status); if (rc) return rc; if (status & I2C_STAT_CMD_COMP) return 0; usleep_range(I2C_CMD_SLEEP_MIN_US, I2C_CMD_SLEEP_MAX_US); } while (time_after(start + I2C_ABORT_TIMEOUT, jiffies)); return -ETIMEDOUT; } static int fsi_i2c_handle_status(struct fsi_i2c_port *port, struct i2c_msg *msg, u32 status) { int rc; u8 fifo_count; if (status & I2C_STAT_ERR) { rc = fsi_i2c_abort(port, status); if (rc) return rc; if (status & I2C_STAT_INV_CMD) return -EINVAL; if (status & (I2C_STAT_PARITY | I2C_STAT_BE_OVERRUN | I2C_STAT_BE_ACCESS)) return -EPROTO; if (status & I2C_STAT_NACK) return -ENXIO; if (status & I2C_STAT_LOST_ARB) return -EAGAIN; if (status & I2C_STAT_STOP_ERR) return -EBADMSG; return -EIO; } if (status & I2C_STAT_DAT_REQ) { fifo_count = FIELD_GET(I2C_STAT_FIFO_COUNT, status); if (msg->flags & I2C_M_RD) return fsi_i2c_read_fifo(port, msg, fifo_count); return fsi_i2c_write_fifo(port, msg, fifo_count); } if (status & I2C_STAT_CMD_COMP) { if (port->xfrd < msg->len) return -ENODATA; return msg->len; } return 0; } static int fsi_i2c_wait(struct fsi_i2c_port *port, struct i2c_msg *msg, unsigned long timeout) { u32 status = 0; int rc; unsigned long start = jiffies; do { rc = fsi_i2c_read_reg(port->master->fsi, I2C_FSI_STAT, &status); if (rc) return rc; if (status & I2C_STAT_ANY_RESP) { rc = fsi_i2c_handle_status(port, msg, status); if (rc < 0) return rc; /* cmd complete and all data xfrd */ if (rc == msg->len) return 0; /* need to xfr more data, but maybe don't need wait */ continue; } usleep_range(I2C_CMD_SLEEP_MIN_US, I2C_CMD_SLEEP_MAX_US); } while (time_after(start + timeout, jiffies)); return -ETIMEDOUT; } static int fsi_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) { int i, rc; unsigned long start_time; struct fsi_i2c_port *port = adap->algo_data; struct fsi_i2c_master *master = port->master; struct i2c_msg *msg; mutex_lock(&master->lock); rc = fsi_i2c_set_port(port); if (rc) goto unlock; for (i = 0; i < num; i++) { msg = msgs + i; start_time = jiffies; rc = fsi_i2c_start(port, msg, i == num - 1); if (rc) goto unlock; rc = fsi_i2c_wait(port, msg, adap->timeout - (jiffies - start_time)); if (rc) goto unlock; } unlock: mutex_unlock(&master->lock); return rc ? : num; } static u32 fsi_i2c_functionality(struct i2c_adapter *adap) { return I2C_FUNC_I2C | I2C_FUNC_PROTOCOL_MANGLING | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA; } static struct i2c_bus_recovery_info fsi_i2c_bus_recovery_info = { .recover_bus = i2c_generic_scl_recovery, .get_scl = fsi_i2c_get_scl, .set_scl = fsi_i2c_set_scl, .get_sda = fsi_i2c_get_sda, .set_sda = fsi_i2c_set_sda, .prepare_recovery = fsi_i2c_prepare_recovery, .unprepare_recovery = fsi_i2c_unprepare_recovery, }; static const struct i2c_algorithm fsi_i2c_algorithm = { .master_xfer = fsi_i2c_xfer, .functionality = fsi_i2c_functionality, }; static int fsi_i2c_probe(struct device *dev) { struct fsi_i2c_master *i2c; struct fsi_i2c_port *port; struct device_node *np; int rc; u32 port_no; i2c = devm_kzalloc(dev, sizeof(*i2c), GFP_KERNEL); if (!i2c) return -ENOMEM; mutex_init(&i2c->lock); i2c->fsi = to_fsi_dev(dev); INIT_LIST_HEAD(&i2c->ports); rc = fsi_i2c_dev_init(i2c); if (rc) return rc; /* Add adapter for each i2c port of the master. */ for_each_available_child_of_node(dev->of_node, np) { rc = of_property_read_u32(np, "reg", &port_no); if (rc || port_no > USHRT_MAX) continue; port = kzalloc(sizeof(*port), GFP_KERNEL); if (!port) break; port->master = i2c; port->port = port_no; port->adapter.owner = THIS_MODULE; port->adapter.dev.of_node = np; port->adapter.dev.parent = dev; port->adapter.algo = &fsi_i2c_algorithm; port->adapter.bus_recovery_info = &fsi_i2c_bus_recovery_info; port->adapter.algo_data = port; snprintf(port->adapter.name, sizeof(port->adapter.name), "i2c_bus-%u", port_no); rc = i2c_add_adapter(&port->adapter); if (rc < 0) { dev_err(dev, "Failed to register adapter: %d\n", rc); kfree(port); continue; } list_add(&port->list, &i2c->ports); } dev_set_drvdata(dev, i2c); return 0; } static int fsi_i2c_remove(struct device *dev) { struct fsi_i2c_master *i2c = dev_get_drvdata(dev); struct fsi_i2c_port *port, *tmp; list_for_each_entry_safe(port, tmp, &i2c->ports, list) { list_del(&port->list); i2c_del_adapter(&port->adapter); kfree(port); } return 0; } static const struct fsi_device_id fsi_i2c_ids[] = { { FSI_ENGID_I2C, FSI_VERSION_ANY }, { } }; static struct fsi_driver fsi_i2c_driver = { .id_table = fsi_i2c_ids, .drv = { .name = "i2c-fsi", .bus = &fsi_bus_type, .probe = fsi_i2c_probe, .remove = fsi_i2c_remove, }, }; module_fsi_driver(fsi_i2c_driver); MODULE_AUTHOR("Eddie James <eajames@us.ibm.com>"); MODULE_DESCRIPTION("FSI attached I2C master"); MODULE_LICENSE("GPL");
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