diff options
Diffstat (limited to 'src/northbridge/intel/i440bx/raminit.c')
| -rw-r--r-- | src/northbridge/intel/i440bx/raminit.c | 21 |
1 files changed, 9 insertions, 12 deletions
diff --git a/src/northbridge/intel/i440bx/raminit.c b/src/northbridge/intel/i440bx/raminit.c index b51a0e67b4..19990b5b70 100644 --- a/src/northbridge/intel/i440bx/raminit.c +++ b/src/northbridge/intel/i440bx/raminit.c @@ -509,44 +509,41 @@ static void sdram_enable(int controllers, const struct mem_controller *ctrl) { int i; - /* TODO: Use a delay here? Needed? */ - mdelay(200); + /* 0. Wait until power/voltages and clocks are stable (200us). */ + udelay(200); - /* TODO: How long should the delays be? Fix later. */ - - /* 1. Apply NOP. */ + /* 1. Apply NOP. Wait 200 clock cycles (200us should do). */ PRINT_DEBUG("RAM Enable 1: Apply NOP\r\n"); do_ram_command(ctrl, RAM_COMMAND_NOP, 0); - mdelay(10); + udelay(200); /* 2. Precharge all. Wait tRP. */ PRINT_DEBUG("RAM Enable 2: Precharge all\r\n"); do_ram_command(ctrl, RAM_COMMAND_PRECHARGE, 0); - mdelay(10); + udelay(1); /* 3. Perform 8 refresh cycles. Wait tRC each time. */ PRINT_DEBUG("RAM Enable 3: CBR\r\n"); for (i = 0; i < 8; i++) { do_ram_command(ctrl, RAM_COMMAND_CBR, 0); - mdelay(10); + udelay(1); } /* 4. Mode register set. Wait two memory cycles. */ PRINT_DEBUG("RAM Enable 4: Mode register set\r\n"); do_ram_command(ctrl, RAM_COMMAND_MRS, 0x1d0); - mdelay(10); - mdelay(10); + udelay(2); /* 5. Normal operation. */ PRINT_DEBUG("RAM Enable 5: Normal operation\r\n"); do_ram_command(ctrl, RAM_COMMAND_NORMAL, 0); - mdelay(10); + udelay(1); /* 6. Finally enable refresh. */ PRINT_DEBUG("RAM Enable 6: Enable refresh\r\n"); // pci_write_config8(ctrl->d0, PMCR, 0x10); spd_enable_refresh(ctrl); - mdelay(10); + udelay(1); PRINT_DEBUG("Northbridge following SDRAM init:\r\n"); DUMPNORTH(); |