i2c-stub.c - I2C/SMBus chip emulator
Copyright (c) 2004 Mark M. Hoffman <mhoffman@lightlink.com>
- Copyright (C) 2007, 2012 Jean Delvare <jdelvare@suse.de>
+ Copyright (C) 2007-2014 Jean Delvare <jdelvare@suse.de>
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
#include <linux/slab.h>
#include <linux/errno.h>
#include <linux/i2c.h>
+#include <linux/list.h>
#define MAX_CHIPS 10
-#define STUB_FUNC (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | \
- I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | \
- I2C_FUNC_SMBUS_I2C_BLOCK)
+
+/*
+ * Support for I2C_FUNC_SMBUS_BLOCK_DATA is disabled by default and must
+ * be enabled explicitly by setting the I2C_FUNC_SMBUS_BLOCK_DATA bits
+ * in the 'functionality' module parameter.
+ */
+#define STUB_FUNC_DEFAULT \
+ (I2C_FUNC_SMBUS_QUICK | I2C_FUNC_SMBUS_BYTE | \
+ I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA | \
+ I2C_FUNC_SMBUS_I2C_BLOCK)
+
+#define STUB_FUNC_ALL \
+ (STUB_FUNC_DEFAULT | I2C_FUNC_SMBUS_BLOCK_DATA)
static unsigned short chip_addr[MAX_CHIPS];
module_param_array(chip_addr, ushort, NULL, S_IRUGO);
MODULE_PARM_DESC(chip_addr,
"Chip addresses (up to 10, between 0x03 and 0x77)");
-static unsigned long functionality = STUB_FUNC;
+static unsigned long functionality = STUB_FUNC_DEFAULT;
module_param(functionality, ulong, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(functionality, "Override functionality bitfield");
+/* Some chips have banked register ranges */
+
+static u8 bank_reg[MAX_CHIPS];
+module_param_array(bank_reg, byte, NULL, S_IRUGO);
+MODULE_PARM_DESC(bank_reg, "Bank register");
+
+static u8 bank_mask[MAX_CHIPS];
+module_param_array(bank_mask, byte, NULL, S_IRUGO);
+MODULE_PARM_DESC(bank_mask, "Bank value mask");
+
+static u8 bank_start[MAX_CHIPS];
+module_param_array(bank_start, byte, NULL, S_IRUGO);
+MODULE_PARM_DESC(bank_start, "First banked register");
+
+static u8 bank_end[MAX_CHIPS];
+module_param_array(bank_end, byte, NULL, S_IRUGO);
+MODULE_PARM_DESC(bank_end, "Last banked register");
+
+struct smbus_block_data {
+ struct list_head node;
+ u8 command;
+ u8 len;
+ u8 block[I2C_SMBUS_BLOCK_MAX];
+};
+
struct stub_chip {
u8 pointer;
u16 words[256]; /* Byte operations use the LSB as per SMBus
specification */
+ struct list_head smbus_blocks;
+
+ /* For chips with banks, extra registers are allocated dynamically */
+ u8 bank_reg;
+ u8 bank_shift;
+ u8 bank_mask;
+ u8 bank_sel; /* Currently selected bank */
+ u8 bank_start;
+ u8 bank_end;
+ u16 bank_size;
+ u16 *bank_words; /* Room for bank_mask * bank_size registers */
};
static struct stub_chip *stub_chips;
+static int stub_chips_nr;
+
+static struct smbus_block_data *stub_find_block(struct device *dev,
+ struct stub_chip *chip,
+ u8 command, bool create)
+{
+ struct smbus_block_data *b, *rb = NULL;
+
+ list_for_each_entry(b, &chip->smbus_blocks, node) {
+ if (b->command == command) {
+ rb = b;
+ break;
+ }
+ }
+ if (rb == NULL && create) {
+ rb = devm_kzalloc(dev, sizeof(*rb), GFP_KERNEL);
+ if (rb == NULL)
+ return rb;
+ rb->command = command;
+ list_add(&rb->node, &chip->smbus_blocks);
+ }
+ return rb;
+}
+
+static u16 *stub_get_wordp(struct stub_chip *chip, u8 offset)
+{
+ if (chip->bank_sel &&
+ offset >= chip->bank_start && offset <= chip->bank_end)
+ return chip->bank_words +
+ (chip->bank_sel - 1) * chip->bank_size +
+ offset - chip->bank_start;
+ else
+ return chip->words + offset;
+}
/* Return negative errno on error. */
static s32 stub_xfer(struct i2c_adapter *adap, u16 addr, unsigned short flags,
s32 ret;
int i, len;
struct stub_chip *chip = NULL;
+ struct smbus_block_data *b;
+ u16 *wordp;
/* Search for the right chip */
- for (i = 0; i < MAX_CHIPS && chip_addr[i]; i++) {
+ for (i = 0; i < stub_chips_nr; i++) {
if (addr == chip_addr[i]) {
chip = stub_chips + i;
break;
"smbus byte - addr 0x%02x, wrote 0x%02x.\n",
addr, command);
} else {
- data->byte = chip->words[chip->pointer++] & 0xff;
+ wordp = stub_get_wordp(chip, chip->pointer++);
+ data->byte = *wordp & 0xff;
dev_dbg(&adap->dev,
"smbus byte - addr 0x%02x, read 0x%02x.\n",
addr, data->byte);
break;
case I2C_SMBUS_BYTE_DATA:
+ wordp = stub_get_wordp(chip, command);
if (read_write == I2C_SMBUS_WRITE) {
- chip->words[command] &= 0xff00;
- chip->words[command] |= data->byte;
+ *wordp &= 0xff00;
+ *wordp |= data->byte;
dev_dbg(&adap->dev,
"smbus byte data - addr 0x%02x, wrote 0x%02x at 0x%02x.\n",
addr, data->byte, command);
+
+ /* Set the bank as needed */
+ if (chip->bank_words && command == chip->bank_reg) {
+ chip->bank_sel =
+ (data->byte >> chip->bank_shift)
+ & chip->bank_mask;
+ dev_dbg(&adap->dev,
+ "switching to bank %u.\n",
+ chip->bank_sel);
+ }
} else {
- data->byte = chip->words[command] & 0xff;
+ data->byte = *wordp & 0xff;
dev_dbg(&adap->dev,
"smbus byte data - addr 0x%02x, read 0x%02x at 0x%02x.\n",
addr, data->byte, command);
break;
case I2C_SMBUS_WORD_DATA:
+ wordp = stub_get_wordp(chip, command);
if (read_write == I2C_SMBUS_WRITE) {
- chip->words[command] = data->word;
+ *wordp = data->word;
dev_dbg(&adap->dev,
"smbus word data - addr 0x%02x, wrote 0x%04x at 0x%02x.\n",
addr, data->word, command);
} else {
- data->word = chip->words[command];
+ data->word = *wordp;
dev_dbg(&adap->dev,
"smbus word data - addr 0x%02x, read 0x%04x at 0x%02x.\n",
addr, data->word, command);
break;
case I2C_SMBUS_I2C_BLOCK_DATA:
+ /*
+ * We ignore banks here, because banked chips don't use I2C
+ * block transfers
+ */
+ if (data->block[0] > 256 - command) /* Avoid overrun */
+ data->block[0] = 256 - command;
len = data->block[0];
if (read_write == I2C_SMBUS_WRITE) {
for (i = 0; i < len; i++) {
ret = 0;
break;
+ case I2C_SMBUS_BLOCK_DATA:
+ /*
+ * We ignore banks here, because chips typically don't use both
+ * banks and SMBus block transfers
+ */
+ b = stub_find_block(&adap->dev, chip, command, false);
+ if (read_write == I2C_SMBUS_WRITE) {
+ len = data->block[0];
+ if (len == 0 || len > I2C_SMBUS_BLOCK_MAX) {
+ ret = -EINVAL;
+ break;
+ }
+ if (b == NULL) {
+ b = stub_find_block(&adap->dev, chip, command,
+ true);
+ if (b == NULL) {
+ ret = -ENOMEM;
+ break;
+ }
+ }
+ /* Largest write sets read block length */
+ if (len > b->len)
+ b->len = len;
+ for (i = 0; i < len; i++)
+ b->block[i] = data->block[i + 1];
+ /* update for byte and word commands */
+ chip->words[command] = (b->block[0] << 8) | b->len;
+ dev_dbg(&adap->dev,
+ "smbus block data - addr 0x%02x, wrote %d bytes at 0x%02x.\n",
+ addr, len, command);
+ } else {
+ if (b == NULL) {
+ dev_dbg(&adap->dev,
+ "SMBus block read command without prior block write not supported\n");
+ ret = -EOPNOTSUPP;
+ break;
+ }
+ len = b->len;
+ data->block[0] = len;
+ for (i = 0; i < len; i++)
+ data->block[i + 1] = b->block[i];
+ dev_dbg(&adap->dev,
+ "smbus block data - addr 0x%02x, read %d bytes at 0x%02x.\n",
+ addr, len, command);
+ }
+
+ ret = 0;
+ break;
+
default:
dev_dbg(&adap->dev, "Unsupported I2C/SMBus command\n");
ret = -EOPNOTSUPP;
static u32 stub_func(struct i2c_adapter *adapter)
{
- return STUB_FUNC & functionality;
+ return STUB_FUNC_ALL & functionality;
}
static const struct i2c_algorithm smbus_algorithm = {
.name = "SMBus stub driver",
};
+static int __init i2c_stub_allocate_banks(int i)
+{
+ struct stub_chip *chip = stub_chips + i;
+
+ chip->bank_reg = bank_reg[i];
+ chip->bank_start = bank_start[i];
+ chip->bank_end = bank_end[i];
+ chip->bank_size = bank_end[i] - bank_start[i] + 1;
+
+ /* We assume that all bits in the mask are contiguous */
+ chip->bank_mask = bank_mask[i];
+ while (!(chip->bank_mask & 1)) {
+ chip->bank_shift++;
+ chip->bank_mask >>= 1;
+ }
+
+ chip->bank_words = kzalloc(chip->bank_mask * chip->bank_size *
+ sizeof(u16), GFP_KERNEL);
+ if (!chip->bank_words)
+ return -ENOMEM;
+
+ pr_debug("i2c-stub: Allocated %u banks of %u words each (registers 0x%02x to 0x%02x)\n",
+ chip->bank_mask, chip->bank_size, chip->bank_start,
+ chip->bank_end);
+
+ return 0;
+}
+
+static void i2c_stub_free(void)
+{
+ int i;
+
+ for (i = 0; i < stub_chips_nr; i++)
+ kfree(stub_chips[i].bank_words);
+ kfree(stub_chips);
+}
+
static int __init i2c_stub_init(void)
{
int i, ret;
}
/* Allocate memory for all chips at once */
- stub_chips = kzalloc(i * sizeof(struct stub_chip), GFP_KERNEL);
+ stub_chips_nr = i;
+ stub_chips = kcalloc(stub_chips_nr, sizeof(struct stub_chip),
+ GFP_KERNEL);
if (!stub_chips) {
pr_err("i2c-stub: Out of memory\n");
return -ENOMEM;
}
+ for (i = 0; i < stub_chips_nr; i++) {
+ INIT_LIST_HEAD(&stub_chips[i].smbus_blocks);
+
+ /* Allocate extra memory for banked register ranges */
+ if (bank_mask[i]) {
+ ret = i2c_stub_allocate_banks(i);
+ if (ret)
+ goto fail_free;
+ }
+ }
ret = i2c_add_adapter(&stub_adapter);
if (ret)
- kfree(stub_chips);
+ goto fail_free;
+
+ return 0;
+
+ fail_free:
+ i2c_stub_free();
return ret;
}
static void __exit i2c_stub_exit(void)
{
i2c_del_adapter(&stub_adapter);
- kfree(stub_chips);
+ i2c_stub_free();
}
MODULE_AUTHOR("Mark M. Hoffman <mhoffman@lightlink.com>");
git.openpandora.org / pandora-kernel.git / blobdiff