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#include "linux_syscall.h"
#include "linux_console.h"
inline int log2(int value)
{
/* __builtin_bsr is a exactly equivalent to the x86 machine
* instruction with the exception that it returns -1
* when the value presented to it is zero.
* Otherwise __builtin_bsr returns the zero based index of
* the highest bit set.
*/
return __builtin_bsr(value);
}
static int smbus_read_byte(unsigned device, unsigned address)
{
static const unsigned char dimm[] = {
0x80, 0x08, 0x07, 0x0d, 0x0a, 0x02, 0x48, 0x00, 0x04, 0x60, 0x70, 0x02, 0x82, 0x08, 0x08, 0x01,
0x0e, 0x04, 0x0c, 0x01, 0x02, 0x20, 0x00, 0x75, 0x70, 0x00, 0x00, 0x48, 0x30, 0x48, 0x2a, 0x40,
0x80, 0x80, 0x45, 0x45, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x33,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0x80, 0x08, 0x07, 0x0d, 0x0a, 0x02, 0x48, 0x00, 0x04, 0x60, 0x70, 0x02, 0x82, 0x08, 0x08, 0x01,
0x0e, 0x04, 0x0c, 0x01, 0x02, 0x20, 0x00, 0x75, 0x70, 0x00, 0x00, 0x48, 0x30, 0x48, 0x2a, 0x40,
0x80, 0x80, 0x45, 0x45, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x33,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
};
return dimm[(device << 8) + address];
}
#define SMBUS_MEM_DEVICE_START 0x00
#define SMBUS_MEM_DEVICE_END 0x01
#define SMBUS_MEM_DEVICE_INC 1
/* Function 2 */
#define DRAM_CONFIG_HIGH 0x94
#define DCH_MEMCLK_SHIFT 20
#define DCH_MEMCLK_MASK 7
#define DCH_MEMCLK_100MHZ 0
#define DCH_MEMCLK_133MHZ 2
#define DCH_MEMCLK_166MHZ 5
#define DCH_MEMCLK_200MHZ 7
/* Function 3 */
#define NORTHBRIDGE_CAP 0xE8
#define NBCAP_128Bit 0x0001
#define NBCAP_MP 0x0002
#define NBCAP_BIG_MP 0x0004
#define NBCAP_ECC 0x0004
#define NBCAP_CHIPKILL_ECC 0x0010
#define NBCAP_MEMCLK_SHIFT 5
#define NBCAP_MEMCLK_MASK 3
#define NBCAP_MEMCLK_100MHZ 3
#define NBCAP_MEMCLK_133MHZ 2
#define NBCAP_MEMCLK_166MHZ 1
#define NBCAP_MEMCLK_200MHZ 0
#define NBCAP_MEMCTRL 0x0100
typedef unsigned char uint8_t;
typedef unsigned int uint32_t;
static unsigned spd_to_dimm(unsigned device)
{
return (device - SMBUS_MEM_DEVICE_START);
}
static void disable_dimm(unsigned index)
{
print_debug("disabling dimm");
print_debug_hex8(index);
print_debug("\n");
#if 0
pci_write_config32(PCI_DEV(0, 0x18, 2), DRAM_CSBASE + (((index << 1)+0)<<2), 0);
pci_write_config32(PCI_DEV(0, 0x18, 2), DRAM_CSBASE + (((index << 1)+1)<<2), 0);
#endif
}
struct mem_param {
uint8_t cycle_time;
uint32_t dch_memclk;
};
static const struct mem_param *get_mem_param(unsigned min_cycle_time)
{
static const struct mem_param speed[] = {
{
.cycle_time = 0xa0,
.dch_memclk = DCH_MEMCLK_100MHZ << DCH_MEMCLK_SHIFT,
},
{
.cycle_time = 0x75,
.dch_memclk = DCH_MEMCLK_133MHZ << DCH_MEMCLK_SHIFT,
},
{
.cycle_time = 0x60,
.dch_memclk = DCH_MEMCLK_166MHZ << DCH_MEMCLK_SHIFT,
},
{
.cycle_time = 0x50,
.dch_memclk = DCH_MEMCLK_200MHZ << DCH_MEMCLK_SHIFT,
},
{
.cycle_time = 0x00,
},
};
const struct mem_param *param;
for(param = &speed[0]; param->cycle_time ; param++) {
if (min_cycle_time > (param+1)->cycle_time) {
break;
}
}
if (!param->cycle_time) {
die("min_cycle_time to low");
}
return param;
}
#if 1
static void debug(int c)
{
print_debug_char(c);
print_debug_char('\n');
}
#endif
static const struct mem_param *spd_set_memclk(void)
{
/* Compute the minimum cycle time for these dimms */
const struct mem_param *param;
unsigned min_cycle_time, min_latency;
unsigned device;
uint32_t value;
static const int latency_indices[] = { 26, 23, 9 };
static const unsigned char min_cycle_times[] = {
[NBCAP_MEMCLK_200MHZ] = 0x50, /* 5ns */
[NBCAP_MEMCLK_166MHZ] = 0x60, /* 6ns */
[NBCAP_MEMCLK_133MHZ] = 0x75, /* 7.5ns */
[NBCAP_MEMCLK_100MHZ] = 0xa0, /* 10ns */
};
#if 0
value = pci_read_config32(PCI_DEV(0, 0x18, 3), NORTHBRIDGE_CAP);
#else
value = 0x50;
#endif
min_cycle_time = min_cycle_times[(value >> NBCAP_MEMCLK_SHIFT) & NBCAP_MEMCLK_MASK];
min_latency = 2;
#if 1
print_debug("min_cycle_time: ");
print_debug_hex8(min_cycle_time);
print_debug(" min_latency: ");
print_debug_hex8(min_latency);
print_debug("\n");
#endif
/* Compute the least latency with the fastest clock supported
* by both the memory controller and the dimms.
*/
for(device = SMBUS_MEM_DEVICE_START;
device <= SMBUS_MEM_DEVICE_END;
device += SMBUS_MEM_DEVICE_INC)
{
int new_cycle_time, new_latency;
int index;
int latencies;
int latency;
debug('A');
/* First find the supported CAS latencies
* Byte 18 for DDR SDRAM is interpreted:
* bit 0 == CAS Latency = 1.0
* bit 1 == CAS Latency = 1.5
* bit 2 == CAS Latency = 2.0
* bit 3 == CAS Latency = 2.5
* bit 4 == CAS Latency = 3.0
* bit 5 == CAS Latency = 3.5
* bit 6 == TBD
* bit 7 == TBD
*/
new_cycle_time = 0xa0;
new_latency = 5;
latencies = smbus_read_byte(device, 18);
if (latencies <= 0) continue;
debug('B');
/* Compute the lowest cas latency supported */
latency = log2(latencies) -2;
/* Loop through and find a fast clock with a low latency */
for(index = 0; index < 3; index++, latency++) {
int value;
debug('C');
if ((latency < 2) || (latency > 4) ||
(!(latencies & (1 << latency)))) {
continue;
}
debug('D');
value = smbus_read_byte(device, latency_indices[index]);
if (value < 0) continue;
debug('E');
/* Only increase the latency if we decreas the clock */
if ((value >= min_cycle_time) && (value < new_cycle_time)) {
new_cycle_time = value;
new_latency = latency;
#if 1
print_debug("device: ");
print_debug_hex8(device);
print_debug(" new_cycle_time: ");
print_debug_hex8(new_cycle_time);
print_debug(" new_latency: ");
print_debug_hex8(new_latency);
print_debug("\n");
#endif
}
debug('G');
}
debug('H');
#if 1
print_debug("device: ");
print_debug_hex8(device);
print_debug(" new_cycle_time: ");
print_debug_hex8(new_cycle_time);
print_debug(" new_latency: ");
print_debug_hex8(new_latency);
print_debug("\n");
#endif
if (new_latency > 4){
continue;
}
debug('I');
/* Does min_latency need to be increased? */
if (new_cycle_time > min_cycle_time) {
min_cycle_time = new_cycle_time;
}
/* Does min_cycle_time need to be increased? */
if (new_latency > min_latency) {
min_latency = new_latency;
}
#if 1
print_debug("device: ");
print_debug_hex8(device);
print_debug(" min_cycle_time: ");
print_debug_hex8(min_cycle_time);
print_debug(" min_latency: ");
print_debug_hex8(min_latency);
print_debug("\n");
#endif
}
/* Make a second pass through the dimms and disable
* any that cannot support the selected memclk and cas latency.
*/
for(device = SMBUS_MEM_DEVICE_START;
device <= SMBUS_MEM_DEVICE_END;
device += SMBUS_MEM_DEVICE_INC)
{
int latencies;
int latency;
int index;
int value;
int dimm;
latencies = smbus_read_byte(device, 18);
if (latencies <= 0) {
goto dimm_err;
}
/* Compute the lowest cas latency supported */
latency = log2(latencies) -2;
/* Walk through searching for the selected latency */
for(index = 0; index < 3; index++, latency++) {
if (!(latencies & (1 << latency))) {
continue;
}
if (latency == min_latency)
break;
}
/* If I can't find the latency or my index is bad error */
if ((latency != min_latency) || (index >= 3)) {
goto dimm_err;
}
/* Read the min_cycle_time for this latency */
value = smbus_read_byte(device, latency_indices[index]);
/* All is good if the selected clock speed
* is what I need or slower.
*/
if (value <= min_cycle_time) {
continue;
}
/* Otherwise I have an error, disable the dimm */
dimm_err:
disable_dimm(spd_to_dimm(device));
}
#if 1
print_debug("min_cycle_time: ");
print_debug_hex8(min_cycle_time);
print_debug(" min_latency: ");
print_debug_hex8(min_latency);
print_debug("\n");
#endif
/* Now that I know the minimum cycle time lookup the memory parameters */
param = get_mem_param(min_cycle_time);
#if 0
/* Update DRAM Config High with our selected memory speed */
value = pci_read_config32(PCI_DEV(0, 0x18, 2), DRAM_CONFIG_HIGH);
value &= ~(DCH_MEMCLK_MASK << DCH_MEMCLK_SHIFT);
value |= param->dch_memclk;
pci_write_config32(PCI_DEV(0, 0x18, 2), DRAM_CONFIG_HIGH, value);
static const unsigned latencies[] = { 1, 5, 2 };
/* Update DRAM Timing Low wiht our selected cas latency */
value = pci_read_config32(PCI_DEV(0, 0x18, 2), DRAM_CONFIG_LOW);
value &= ~7;
value |= latencies[min_latency - 2];
pci_write_config32(PCI_DEV(0, 0x18, 2), DRAM_CONFIG_LOW, value);
#endif
return param;
}
static void main(void)
{
const struct mem_param *param;
param = spd_set_memclk();
_exit(0);
}
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