diff options
| -rw-r--r-- | board/freescale/t4qds/t4qds.c | 39 | ||||
| -rw-r--r-- | doc/README.t4240qds | 24 |
2 files changed, 61 insertions, 2 deletions
diff --git a/board/freescale/t4qds/t4qds.c b/board/freescale/t4qds/t4qds.c index d521008e7a..26539db2df 100644 --- a/board/freescale/t4qds/t4qds.c +++ b/board/freescale/t4qds/t4qds.c @@ -234,7 +234,7 @@ static inline int set_voltage(u8 vid) } -static int adjust_vdd(void) +static int adjust_vdd(ulong vdd_override) { int re_enable = disable_interrupts(); ccsr_gur_t __iomem *gur = @@ -243,6 +243,8 @@ static int adjust_vdd(void) u8 vid, vid_current; int vdd_target, vdd_current, vdd_last; int ret; + unsigned long vdd_string_override; + char *vdd_string; static const uint16_t vdd[32] = { 0, /* unused */ 9875, /* 0.9875V */ @@ -292,6 +294,19 @@ static int adjust_vdd(void) FSL_CORENET_DCFG_FUSESR_ALTVID_MASK; } vdd_target = vdd[vid]; + + /* check override variable for overriding VDD */ + vdd_string = getenv("t4240qds_vdd_mv"); + if (vdd_override == 0 && vdd_string && + !strict_strtoul(vdd_string, 10, &vdd_string_override)) + vdd_override = vdd_string_override; + if (vdd_override >= 819 && vdd_override <= 1212) { + vdd_target = vdd_override * 10; /* convert to 1/10 mV */ + debug("VDD override is %lu\n", vdd_override); + } else if (vdd_override != 0) { + printf("Invalid value.\n"); + } + if (vdd_target == 0) { debug("VID: VID not used\n"); ret = 0; @@ -511,7 +526,7 @@ int board_early_init_r(void) * Adjust core voltage according to voltage ID * This function changes I2C mux to channel 2. */ - if (adjust_vdd()) + if (adjust_vdd(0)) printf("Warning: Adjusting core voltage failed.\n"); /* Configure board SERDES ports crossbar */ @@ -801,3 +816,23 @@ void qixis_dump_switch(void) i + 1, byte_to_binary_mask(sw[i], mask[i], buf), sw[i]); } } + +static int do_vdd_adjust(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[]) +{ + ulong override; + + if (argc < 2) + return CMD_RET_USAGE; + if (!strict_strtoul(argv[1], 10, &override)) + adjust_vdd(override); /* the value is checked by callee */ + else + return CMD_RET_USAGE; + + return 0; +} + +U_BOOT_CMD( + vdd_override, 2, 0, do_vdd_adjust, + "Override VDD", + "- override with the voltage specified in mV, eg. 1050" +); diff --git a/doc/README.t4240qds b/doc/README.t4240qds index 677d120a80..19e8a8ae1f 100644 --- a/doc/README.t4240qds +++ b/doc/README.t4240qds @@ -96,3 +96,27 @@ The addresses in brackets are physical addresses. 0x0_ffff_f000 (0x0_7fff_fff0) - 0x0_ffff_ffff 4KB Boot page translation for secondary cores The physical address of the last (boot page translation) varies with the actual DDR size. + +Voltage ID and VDD override +-------------------- +T4240 has a VID feature. U-boot reads the VID efuses and adjust the voltage +accordingly. The voltage can also be override by command vdd_override. The +syntax is + +vdd_override <voltage in mV>, eg. 1050 is for 1.050v. + +Upon success, the actual voltage will be read back. The value is checked +for safety and any invalid value will not adjust the voltage. + +Another way to override VDD is to use environmental variable, in case of using +command is too late for some debugging. The syntax is + +setenv t4240qds_vdd_mv <voltage in mV> +saveenv +reset + +The override voltage takes effect when booting. + +Note: voltage adjustment needs to be done step by step. Changing voltage too +rapidly may cause current surge. The voltage stepping is done by software. +Users can set the final voltage directly. |