/*
 * This file is part of the coreboot project.
 *
 * Copyright (C) 2007 Rudolf Marek <r.marek@assembler.cz>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License v2 as published by
 * the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301 USA
 */

#include <device/device.h>
#include <device/pci.h>
#include <device/pci_ids.h>
#include <console/console.h>
#include <cpu/x86/msr.h>
#include <cpu/amd/mtrr.h>
#include <bitops.h>
#include "k8t890.h"

static void dram_enable(struct device *dev)
{
	msr_t msr;
	u16 reg;

	/*
	 * Enable Lowest Interrupt arbitration for APIC, enable NB APIC
	 * decoding, MSI support, no SMRAM, compatible SMM.
	 */
	pci_write_config8(dev, 0x86, 0x39);

	/*
	 * We want to use the 0xC0000-0xEFFFF as RAM mark area as RW, even if
	 * memory is doing K8 the DMA from SB will fail if we have it wrong,
	 * AND even we have it here, we must later copy it to SB to make it work :/
	 */

	/* For CC000-CFFFF, bits 7:6 (10 = REn, 01 = WEn) bits 1:0 for
	 * C0000-C3FFF etc.
	 */
	pci_write_config8(dev, 0x80, 0xff);
	/* For page D0000-DFFFF */
	pci_write_config8(dev, 0x81, 0xff);
	/* For page E0000-EFFFF */
	pci_write_config8(dev, 0x82, 0xff);
	pci_write_config8(dev, 0x83, 0x30);

	msr = rdmsr(TOP_MEM);
	reg = pci_read_config16(dev, 0x84);
	reg &= 0xf;
	pci_write_config16(dev, 0x84, (msr.lo >> 16) | reg);

	reg = pci_read_config16(dev, 0x88);
	reg &= 0xf800;

	/* The Address Next to the Last Valid DRAM Address */
	pci_write_config16(dev, 0x88, (msr.lo >> 24) | reg);

}

static void dram_enable_k8m890(struct device *dev)
{
	dram_enable(dev);

	/* enable VGA, so the bridges gets VGA_EN and resources are set */
	pci_write_config8(dev, 0xa1, 0x80);
}

static struct resource *resmax;

static void get_memres(void *gp, struct device *dev, struct resource *res)
{
	unsigned int *fbsize = (unsigned int *) gp;
	uint64_t proposed_base = res->base + res->size - *fbsize;

	printk_debug("get_memres: res->base=%llx res->size=%llx %d %d %d\n",
			res->base, res->size, (res->size > *fbsize), 
			(!(proposed_base & (*fbsize - 1))),
			(proposed_base < ((uint64_t) 0xffffffff)));

	/* if we fit and also align OK, and must be below 4GB */
	if ((res->size > *fbsize) && (!(proposed_base & (*fbsize - 1))) && 
		(proposed_base < ((uint64_t) 0xffffffff) )) {
		resmax = res;
	}
}


static void dram_init_fb(struct device *dev)
{
	/* Important bits:
	 * Enable the internal GFX bit 7 of reg 0xa1 plus in same reg:
	 * bits 6:4 X fbuffer size will be  2^(X+2) or 100 = 64MB, 101 = 128MB 
	 * bits 3:0 BASE [31:28]
	 * reg 0xa0 bits 7:1 BASE [27:21] bit0 enable CPU access
	 */
	u8 tmp;
	uint64_t proposed_base;
	unsigned int fbsize = (K8M890_FBSIZEMB * 1024 * 1024);

	resmax = NULL;
	search_global_resources(
                IORESOURCE_MEM | IORESOURCE_CACHEABLE, IORESOURCE_MEM | IORESOURCE_CACHEABLE,
                get_memres, (void *) &fbsize);

	/* no space for FB */
	if (!resmax) {
		printk_err("VIA FB: no space for framebuffer in RAM\n");
		return;
	}

	proposed_base = resmax->base + resmax->size - fbsize;
	resmax->size -= fbsize;

	printk_debug("VIA FB proposed base: %llx\n", proposed_base);

	/* Step 1: enable UMA but no FB */
	pci_write_config8(dev, 0xa1, 0x80);

	/* Step 2: enough is just the FB size, the CPU accessible address is not needed */
	tmp = ((log2(K8M890_FBSIZEMB) - 2) << 4) | 0x80;
	pci_write_config8(dev, 0xa1, tmp);

	/* TODO K8 needs some UMA fine tuning too maybe call some generic routine here? */
}

static const struct device_operations dram_ops_t = {
	.read_resources		= pci_dev_read_resources,
	.set_resources		= pci_dev_set_resources,
	.enable_resources	= pci_dev_enable_resources,
	.enable			= dram_enable,
	.ops_pci		= 0,
};

static const struct device_operations dram_ops_m = {
	.read_resources		= pci_dev_read_resources,
	.set_resources		= pci_dev_set_resources,
	.enable_resources	= pci_dev_enable_resources,
	.enable			= dram_enable_k8m890,
	.init			= dram_init_fb,
	.ops_pci		= 0,
};

static const struct pci_driver northbridge_driver_t __pci_driver = {
	.ops	= &dram_ops_t,
	.vendor	= PCI_VENDOR_ID_VIA,
	.device	= PCI_DEVICE_ID_VIA_K8T890CE_3,
};

static const struct pci_driver northbridge_driver_m __pci_driver = {
	.ops	= &dram_ops_m,
	.vendor	= PCI_VENDOR_ID_VIA,
	.device	= PCI_DEVICE_ID_VIA_K8M890CE_3,
};