diff options
Diffstat (limited to 'drivers/thunderbolt/eeprom.c')
| -rw-r--r-- | drivers/thunderbolt/eeprom.c | 189 |
1 files changed, 189 insertions, 0 deletions
diff --git a/drivers/thunderbolt/eeprom.c b/drivers/thunderbolt/eeprom.c new file mode 100644 index 000000000000..f28e40231c9e --- /dev/null +++ b/drivers/thunderbolt/eeprom.c @@ -0,0 +1,189 @@ +/* + * Thunderbolt Cactus Ridge driver - eeprom access + * + * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com> + */ + +#include "tb.h" + +/** + * tb_eeprom_ctl_write() - write control word + */ +static int tb_eeprom_ctl_write(struct tb_switch *sw, struct tb_eeprom_ctl *ctl) +{ + return tb_sw_write(sw, ctl, TB_CFG_SWITCH, sw->cap_plug_events + 4, 1); +} + +/** + * tb_eeprom_ctl_write() - read control word + */ +static int tb_eeprom_ctl_read(struct tb_switch *sw, struct tb_eeprom_ctl *ctl) +{ + return tb_sw_read(sw, ctl, TB_CFG_SWITCH, sw->cap_plug_events + 4, 1); +} + +enum tb_eeprom_transfer { + TB_EEPROM_IN, + TB_EEPROM_OUT, +}; + +/** + * tb_eeprom_active - enable rom access + * + * WARNING: Always disable access after usage. Otherwise the controller will + * fail to reprobe. + */ +static int tb_eeprom_active(struct tb_switch *sw, bool enable) +{ + struct tb_eeprom_ctl ctl; + int res = tb_eeprom_ctl_read(sw, &ctl); + if (res) + return res; + if (enable) { + ctl.access_high = 1; + res = tb_eeprom_ctl_write(sw, &ctl); + if (res) + return res; + ctl.access_low = 0; + return tb_eeprom_ctl_write(sw, &ctl); + } else { + ctl.access_low = 1; + res = tb_eeprom_ctl_write(sw, &ctl); + if (res) + return res; + ctl.access_high = 0; + return tb_eeprom_ctl_write(sw, &ctl); + } +} + +/** + * tb_eeprom_transfer - transfer one bit + * + * If TB_EEPROM_IN is passed, then the bit can be retrieved from ctl->data_in. + * If TB_EEPROM_OUT is passed, then ctl->data_out will be written. + */ +static int tb_eeprom_transfer(struct tb_switch *sw, struct tb_eeprom_ctl *ctl, + enum tb_eeprom_transfer direction) +{ + int res; + if (direction == TB_EEPROM_OUT) { + res = tb_eeprom_ctl_write(sw, ctl); + if (res) + return res; + } + ctl->clock = 1; + res = tb_eeprom_ctl_write(sw, ctl); + if (res) + return res; + if (direction == TB_EEPROM_IN) { + res = tb_eeprom_ctl_read(sw, ctl); + if (res) + return res; + } + ctl->clock = 0; + return tb_eeprom_ctl_write(sw, ctl); +} + +/** + * tb_eeprom_out - write one byte to the bus + */ +static int tb_eeprom_out(struct tb_switch *sw, u8 val) +{ + struct tb_eeprom_ctl ctl; + int i; + int res = tb_eeprom_ctl_read(sw, &ctl); + if (res) + return res; + for (i = 0; i < 8; i++) { + ctl.data_out = val & 0x80; + res = tb_eeprom_transfer(sw, &ctl, TB_EEPROM_OUT); + if (res) + return res; + val <<= 1; + } + return 0; +} + +/** + * tb_eeprom_in - read one byte from the bus + */ +static int tb_eeprom_in(struct tb_switch *sw, u8 *val) +{ + struct tb_eeprom_ctl ctl; + int i; + int res = tb_eeprom_ctl_read(sw, &ctl); + if (res) + return res; + *val = 0; + for (i = 0; i < 8; i++) { + *val <<= 1; + res = tb_eeprom_transfer(sw, &ctl, TB_EEPROM_IN); + if (res) + return res; + *val |= ctl.data_in; + } + return 0; +} + +/** + * tb_eeprom_read_n - read count bytes from offset into val + */ +static int tb_eeprom_read_n(struct tb_switch *sw, u16 offset, u8 *val, + size_t count) +{ + int i, res; + res = tb_eeprom_active(sw, true); + if (res) + return res; + res = tb_eeprom_out(sw, 3); + if (res) + return res; + res = tb_eeprom_out(sw, offset >> 8); + if (res) + return res; + res = tb_eeprom_out(sw, offset); + if (res) + return res; + for (i = 0; i < count; i++) { + res = tb_eeprom_in(sw, val + i); + if (res) + return res; + } + return tb_eeprom_active(sw, false); +} + +int tb_eeprom_read_uid(struct tb_switch *sw, u64 *uid) +{ + u8 data[9]; + struct tb_cap_plug_events cap; + int res; + if (!sw->cap_plug_events) { + tb_sw_warn(sw, "no TB_CAP_PLUG_EVENTS, cannot read eeprom\n"); + return -ENOSYS; + } + res = tb_sw_read(sw, &cap, TB_CFG_SWITCH, sw->cap_plug_events, + sizeof(cap) / 4); + if (res) + return res; + if (!cap.eeprom_ctl.present || cap.eeprom_ctl.not_present) { + tb_sw_warn(sw, "no NVM\n"); + return -ENOSYS; + } + + if (cap.drom_offset > 0xffff) { + tb_sw_warn(sw, "drom offset is larger than 0xffff: %#x\n", + cap.drom_offset); + return -ENXIO; + } + + /* read uid */ + res = tb_eeprom_read_n(sw, cap.drom_offset, data, 9); + if (res) + return res; + /* TODO: check checksum in data[0] */ + *uid = *(u64 *)(data+1); + return 0; +} + + + |