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/* SPDX-License-Identifier: GPL-2.0-only */
#include <device/mmio.h>
#include <console/console.h>
#include <delay.h>
#include "i915_reg.h"
#include "edid.h"
#define GMBUS0_ADDR (mmio + 4 * 0)
#define GMBUS1_ADDR (mmio + 4 * 1)
#define GMBUS2_ADDR (mmio + 4 * 2)
#define GMBUS3_ADDR (mmio + 4 * 3)
#define GMBUS5_ADDR (mmio + 4 * 8)
#define AT24_ADDR 0x50 /* EDID EEPROM */
static void wait_rdy(u8 *mmio)
{
unsigned int try = 100;
while (try--) {
if (read32(GMBUS2_ADDR) & GMBUS_HW_RDY)
return;
udelay(10);
}
}
static void intel_gmbus_stop_bus(u8 *mmio, u8 bus)
{
wait_rdy(mmio);
write32(GMBUS0_ADDR, bus);
wait_rdy(mmio);
write32(GMBUS5_ADDR, 0);
write32(GMBUS1_ADDR, GMBUS_SW_RDY | GMBUS_CYCLE_WAIT | GMBUS_CYCLE_INDEX
| GMBUS_CYCLE_STOP | (0x4 << GMBUS_BYTE_COUNT_SHIFT)
| GMBUS_SLAVE_READ | (AT24_ADDR << 1));
wait_rdy(mmio);
write32(GMBUS5_ADDR, 0);
write32(GMBUS1_ADDR, GMBUS_SW_CLR_INT);
write32(GMBUS1_ADDR, 0);
wait_rdy(mmio);
write32(GMBUS1_ADDR, GMBUS_SW_RDY | GMBUS_CYCLE_STOP | GMBUS_SLAVE_WRITE
| (AT24_ADDR << 1));
wait_rdy(mmio);
write32(GMBUS1_ADDR, GMBUS_SW_RDY | GMBUS_CYCLE_STOP);
write32(GMBUS2_ADDR, GMBUS_INUSE);
}
void intel_gmbus_stop(u8 *mmio)
{
intel_gmbus_stop_bus(mmio, 6);
intel_gmbus_stop_bus(mmio, 2);
}
void intel_gmbus_read_edid(u8 *mmio, u8 bus, u8 slave, u8 *edid, u32 edid_size)
{
int i;
slave &= 0x7f;
edid_size &= 0x1fc;
wait_rdy(mmio);
/* 100 KHz, hold 0ns, */
write32(GMBUS0_ADDR, bus);
wait_rdy(mmio);
/* Ensure index bits are disabled. */
write32(GMBUS5_ADDR, 0);
write32(GMBUS1_ADDR, GMBUS_SW_RDY | GMBUS_CYCLE_WAIT | GMBUS_CYCLE_INDEX
| (slave << 1));
wait_rdy(mmio);
/* Ensure index bits are disabled. */
write32(GMBUS5_ADDR, 0);
write32(GMBUS1_ADDR, GMBUS_SW_RDY | GMBUS_SLAVE_READ | GMBUS_CYCLE_WAIT
| GMBUS_CYCLE_STOP
| (edid_size << GMBUS_BYTE_COUNT_SHIFT) | (slave << 1));
for (i = 0; i < edid_size / 4; i++) {
u32 reg32;
wait_rdy(mmio);
reg32 = read32(GMBUS3_ADDR);
edid[4 * i] = reg32 & 0xff;
edid[4 * i + 1] = (reg32 >> 8) & 0xff;
edid[4 * i + 2] = (reg32 >> 16) & 0xff;
edid[4 * i + 3] = (reg32 >> 24) & 0xff;
}
wait_rdy(mmio);
write32(GMBUS1_ADDR, GMBUS_SW_RDY
| GMBUS_SLAVE_WRITE | GMBUS_CYCLE_WAIT | GMBUS_CYCLE_STOP
| (128 << GMBUS_BYTE_COUNT_SHIFT) | (slave << 1));
wait_rdy(mmio);
write32(GMBUS1_ADDR, GMBUS_SW_RDY | GMBUS_CYCLE_STOP);
write32(GMBUS2_ADDR, GMBUS_INUSE);
printk(BIOS_SPEW, "EDID:\n");
for (i = 0; i < 128; i++) {
printk(BIOS_SPEW, " %02x", edid[i]);
if ((i & 0xf) == 0xf)
printk(BIOS_SPEW, "\n");
}
}
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