static int
ow_send_command(device_t ndev, device_t pdev, struct ow_cmd *cmd)
{
int present, i, bit, tries;
device_t lldev;
struct ow_timing *t;
lldev = device_get_parent(ndev);
/*
* Retry the reset a couple of times before giving up.
*/
tries = 4;
do {
OWLL_RESET_AND_PRESENCE(lldev, &timing_regular, &present);
if (present == 1)
device_printf(ndev, "Reset said no device on bus?.\n");
} while (present == 1 && tries-- > 0);
if (present == 1) {
device_printf(ndev, "Reset said the device wasn't there.\n");
return ENOENT; /* No devices acked the RESET */
}
if (present == -1) {
device_printf(ndev, "Reset discovered bus wired wrong.\n");
return ENOENT;
}
for (i = 0; i < cmd->rom_len; i++)
ow_send_byte(lldev, &timing_regular, cmd->rom_cmd[i]);
for (i = 0; i < cmd->rom_read_len; i++)
ow_read_byte(lldev, &timing_regular, cmd->rom_read + i);
if (cmd->xpt_len) {
/*
* Per AN937, the reset pulse and ROM level are always
* done with the regular timings. Certain ROM commands
* put the device into overdrive mode for the remainder
* of the data transfer, which is why we have to pass the
* timings here. Commands that need to be handled like this
* are expected to be flagged by the client.
*/
t = (cmd->flags & OW_FLAG_OVERDRIVE) ?
&timing_overdrive : &timing_regular;
for (i = 0; i < cmd->xpt_len; i++)
ow_send_byte(lldev, t, cmd->xpt_cmd[i]);
if (cmd->flags & OW_FLAG_READ_BIT) {
memset(cmd->xpt_read, 0, (cmd->xpt_read_len + 7) / 8);
for (i = 0; i < cmd->xpt_read_len; i++) {
OWLL_READ_DATA(lldev, t, &bit);
cmd->xpt_read[i / 8] |= bit << (i % 8);
}
} else {
for (i = 0; i < cmd->xpt_read_len; i++)
ow_read_byte(lldev, t, cmd->xpt_read + i);
}
}
return 0;
}
void ow_match_rom(uint8_t *rom_value, uint8_t pin) {
uint8_t bytes_left = 8;
ow_send_byte(OW_ROM_MATCH, pin);
while(bytes_left-- > 0) {
ow_send_byte(*rom_value++, pin);
}
}
uint8_t ow_search_rom(uint8_t *bit_pattern, uint8_t last_deviation, uint8_t pin) {
uint8_t current_bit = 1;
uint8_t new_deviation = 0;
uint8_t bit_mask = 0x01;
uint8_t bit_a;
uint8_t bit_b;
ow_send_byte(OW_ROM_SEARCH, pin);
while(current_bit <= 64) {
bit_a = ow_read_bit(pin);
bit_b = ow_read_bit(pin);
if(bit_a && bit_b) {
return SEARCH_ERROR;
} else if(bit_a ^ bit_b) {
if(bit_a) {
(*bit_pattern) |= bit_mask;
} else {
(*bit_pattern) &= ~bit_mask;
}
} else {
if(current_bit == last_deviation) {
(*bit_pattern) |= bit_mask;
} else if(current_bit > last_deviation) {
(*bit_pattern) &= ~bit_mask;
new_deviation = current_bit;
} else if(!(*bit_pattern & bit_mask)) {
new_deviation = current_bit;
} else {
}
}
if((*bit_pattern) & bit_mask) {
ow_write_bit1(pin);
} else {
ow_write_bit0(pin);
}
current_bit++;
bit_mask <<= 1;
if(!bit_mask) {
bit_mask = 0x01;
bit_pattern++;
}
}
return new_deviation;
}
