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#include <cpu/amd/gx2def.h>
static void sdram_set_registers(const struct mem_controller *ctrl)
{
}
/* Section 6.1.3, LX processor databooks, BIOS Initialization Sequence
* Section 4.1.4, GX/CS5535 GeodeROM Porting guide */
static void sdram_enable(int controllers, const struct mem_controller *ctrl)
{
int i;
msr_t msr;
/* 2. clock gating for PMode */
msr = rdmsr(0x20002004);
msr.lo &= ~0x04;
msr.lo |= 0x01;
wrmsr(0x20002004, msr);
/* undocmented bits in GX, in LX there are
* 8 bits in PM1_UP_DLY */
msr = rdmsr(0x2000001a);
msr.lo = 0x0101;
wrmsr(0x2000001a, msr);
//print_debug("sdram_enable step 2\n");
/* 3. release CKE mask to enable CKE */
msr = rdmsr(0x2000001d);
msr.lo &= ~(0x03 << 8);
wrmsr(0x2000201d, msr);
//print_debug("sdram_enable step 3\n");
/* 4. set and clear REF_TST 16 times, more shouldn't hurt
* why this is before EMRS and MRS ? */
for (i = 0; i < 19; i++) {
msr = rdmsr(0x20000018);
msr.lo |= (0x01 << 3);
wrmsr(0x20000018, msr);
msr.lo &= ~(0x01 << 3);
wrmsr(0x20000018, msr);
}
//print_debug("sdram_enable step 4\n");
/* 5. set refresh interval */
msr = rdmsr(0x20000018);
msr.lo &= ~(0xffff << 8);
msr.lo |= (0x34 << 8);
wrmsr(0x20000018, msr);
/* set refresh staggering to 4 SDRAM clocks */
msr = rdmsr(0x20000018);
msr.lo &= ~(0x03 << 6);
msr.lo |= (0x00 << 6);
wrmsr(0x20000018, msr);
//print_debug("sdram_enable step 5\n");
/* 6. enable DLL, load Extended Mode Register by set and clear PROG_DRAM */
msr = rdmsr(0x20000018);
msr.lo |= ((0x01 << 28) | 0x01);
wrmsr(0x20000018, msr);
msr.lo &= ~((0x01 << 28) | 0x01);
wrmsr(0x20000018, msr);
//print_debug("sdram_enable step 6\n");
/* 7. Reset DLL, Bit 27 is undocumented in GX datasheet,
* it is documented in LX datasheet */
/* load Mode Register by set and clear PROG_DRAM */
msr = rdmsr(0x20000018);
msr.lo |= ((0x01 << 27) | 0x01);
wrmsr(0x20000018, msr);
msr.lo &= ~((0x01 << 27) | 0x01);
wrmsr(0x20000018, msr);
//print_debug("sdram_enable step 7\n");
/* 8. load Mode Register by set and clear PROG_DRAM */
msr = rdmsr(0x20000018);
msr.lo |= 0x01;
wrmsr(0x20000018, msr);
msr.lo &= ~0x01;
wrmsr(0x20000018, msr);
//print_debug("sdram_enable step 8\n");
/* wait 200 SDCLKs */
for (i = 0; i < 200; i++)
outb(0xaa, 0x80);
/* load RDSYNC */
msr = rdmsr(0x2000001f);
msr.hi = 0x000ff310;
/* the above setting is supposed to be good for "slow" ram. We have found that for
* some dram, at some clock rates, e.g. hynix at 366/244, this will actually
* cause errors. The fix is to just set it to 0x310. Tested on 3 boards
* with 3 different type of dram -- Hynix, PSC, infineon.
* I am leaving this comment here so that at some future time nobody is tempted
* to mess with this setting -- RGM, 9/2006
*/
msr.hi = 0x00000310;
msr.lo = 0x00000000;
wrmsr(0x2000001f, msr);
/* set delay control */
msr = rdmsr(0x4c00000f);
msr.hi = 0x830d415a;
msr.lo = 0x8ea0ad6a;
wrmsr(0x4c00000f, msr);
/* The RAM dll needs a write to lock on so generate a few dummy writes */
/* Note: The descriptor needs to be enabled to point at memory */
volatile unsigned long *ptr;
for (i = 0; i < 5; i++) {
ptr = (void *)i;
*ptr = (unsigned long)i;
}
print_info("RAM DLL lock\n");
}
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