/*
   * Copyright (C) 2001,2002,2003 Broadcom Corporation
   * Copyright (C) 2004 by Ralf Baechle (ralf@linux-mips.org)
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License
   * as published by the Free Software Foundation; either version 2
   * of the License, or (at your option) any later version.
   *
   * 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., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
   */
  
  /*
   * BCM1250-specific PCI support
   *
   * This module provides the glue between Linux's PCI subsystem
   * and the hardware.  We basically provide glue for accessing
   * configuration space, and set up the translation for I/O
   * space accesses.
   *
   * To access configuration space, we use ioremap.  In the 32-bit
   * kernel, this consumes either 4 or 8 page table pages, and 16MB of
   * kernel mapped memory.  Hopefully neither of these should be a huge
   * problem.
   */
  #include <linux/types.h>
  #include <linux/pci.h>
  #include <linux/kernel.h>
  #include <linux/init.h>
  #include <linux/mm.h>
  #include <linux/console.h>
  #include <linux/tty.h>
  #include <linux/vt.h>
  
  #include <asm/io.h>
  
  #include <asm/sibyte/sb1250_defs.h>
  #include <asm/sibyte/sb1250_regs.h>
  #include <asm/sibyte/sb1250_scd.h>
  #include <asm/sibyte/board.h>
  
  /*
   * Macros for calculating offsets into config space given a device
   * structure or dev/fun/reg
   */
  #define CFGOFFSET(bus, devfn, where) (((bus)<<16) + ((devfn)<<8) + (where))
  #define CFGADDR(bus, devfn, where)   CFGOFFSET((bus)->number, (devfn), where)
  
  static void *cfg_space;
  
  #define PCI_BUS_ENABLED 1
  #define LDT_BUS_ENABLED 2
  #define PCI_DEVICE_MODE 4
  
  static int sb1250_bus_status;
  
  #define PCI_BRIDGE_DEVICE  0
  #define LDT_BRIDGE_DEVICE  1
  
  #ifdef CONFIG_SIBYTE_HAS_LDT
  /*
   * HT's level-sensitive interrupts require EOI, which is generated
   * through a 4MB memory-mapped region
   */
  unsigned long ldt_eoi_space;
  #endif
  
  /*
   * Read/write 32-bit values in config space.
   */
  static inline u32 READCFG32(u32 addr)
  {
  	return *(u32 *) (cfg_space + (addr & ~3));
  }
  
  static inline void WRITECFG32(u32 addr, u32 data)
  {
  	*(u32 *) (cfg_space + (addr & ~3)) = data;
  }
  
  int pcibios_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
  {
  	return dev->irq;
  }
  
  /* Do platform specific device initialization at pci_enable_device() time */
  int pcibios_plat_dev_init(struct pci_dev *dev)
  {
  	return 0;
  }
  
  /*
   * Some checks before doing config cycles:
   * In PCI Device Mode, hide everything on bus 0 except the LDT host
   * bridge.  Otherwise, access is controlled by bridge MasterEn bits.
   */
  static int sb1250_pci_can_access(struct pci_bus *bus, int devfn)
  {
  	u32 devno;
  
  	if (!(sb1250_bus_status & (PCI_BUS_ENABLED | PCI_DEVICE_MODE)))
  		return 0;
  
  	if (bus->number == 0) {
  		devno = PCI_SLOT(devfn);
  		if (devno == LDT_BRIDGE_DEVICE)
  			return (sb1250_bus_status & LDT_BUS_ENABLED) != 0;
  		else if (sb1250_bus_status & PCI_DEVICE_MODE)
  			return 0;
  		else
  			return 1;
  	} else
  		return 1;
  }
  
  /*
   * Read/write access functions for various sizes of values
   * in config space.  Return all 1's for disallowed accesses
   * for a kludgy but adequate simulation of master aborts.
   */
  
  static int sb1250_pcibios_read(struct pci_bus *bus, unsigned int devfn,
  			       int where, int size, u32 * val)
  {
  	u32 data = 0;
  
  	if ((size == 2) && (where & 1))
  		return PCIBIOS_BAD_REGISTER_NUMBER;
  	else if ((size == 4) && (where & 3))
  		return PCIBIOS_BAD_REGISTER_NUMBER;
  
  	if (sb1250_pci_can_access(bus, devfn))
  		data = READCFG32(CFGADDR(bus, devfn, where));
  	else
  		data = 0xFFFFFFFF;
  
  	if (size == 1)
  		*val = (data >> ((where & 3) << 3)) & 0xff;
  	else if (size == 2)
  		*val = (data >> ((where & 3) << 3)) & 0xffff;
  	else
  		*val = data;
  
  	return PCIBIOS_SUCCESSFUL;
  }
  
  static int sb1250_pcibios_write(struct pci_bus *bus, unsigned int devfn,
  				int where, int size, u32 val)
  {
  	u32 cfgaddr = CFGADDR(bus, devfn, where);
  	u32 data = 0;
  
  	if ((size == 2) && (where & 1))
  		return PCIBIOS_BAD_REGISTER_NUMBER;
  	else if ((size == 4) && (where & 3))
  		return PCIBIOS_BAD_REGISTER_NUMBER;
  
  	if (!sb1250_pci_can_access(bus, devfn))
  		return PCIBIOS_BAD_REGISTER_NUMBER;
  
  	data = READCFG32(cfgaddr);
  
  	if (size == 1)
  		data = (data & ~(0xff << ((where & 3) << 3))) |
  		    (val << ((where & 3) << 3));
  	else if (size == 2)
  		data = (data & ~(0xffff << ((where & 3) << 3))) |
  		    (val << ((where & 3) << 3));
  	else
  		data = val;
  
  	WRITECFG32(cfgaddr, data);
  
  	return PCIBIOS_SUCCESSFUL;
  }
  
  struct pci_ops sb1250_pci_ops = {
  	.read	= sb1250_pcibios_read,
  	.write	= sb1250_pcibios_write,
  };
  
  static struct resource sb1250_mem_resource = {
  	.name	= "SB1250 PCI MEM",
  	.start	= 0x40000000UL,
  	.end	= 0x5fffffffUL,
  	.flags	= IORESOURCE_MEM,
  };
  
  static struct resource sb1250_io_resource = {
  	.name	= "SB1250 PCI I/O",
  	.start	= 0x00000000UL,
  	.end	= 0x01ffffffUL,
  	.flags	= IORESOURCE_IO,
  };
  
  struct pci_controller sb1250_controller = {
  	.pci_ops	= &sb1250_pci_ops,
  	.mem_resource	= &sb1250_mem_resource,
  	.io_resource	= &sb1250_io_resource,
  };
  
  static int __init sb1250_pcibios_init(void)
  {
  	void __iomem *io_map_base;
  	uint32_t cmdreg;
  	uint64_t reg;
  
  	/* CFE will assign PCI resources */
  	pci_set_flags(PCI_PROBE_ONLY);
  
  	/* Avoid ISA compat ranges.  */
  	PCIBIOS_MIN_IO = 0x00008000UL;
  	PCIBIOS_MIN_MEM = 0x01000000UL;
  
  	/* Set I/O resource limits.  */
  	ioport_resource.end = 0x01ffffffUL;	/* 32MB accessible by sb1250 */
  	iomem_resource.end = 0xffffffffUL;	/* no HT support yet */
  
  	cfg_space =
  	    ioremap(A_PHYS_LDTPCI_CFG_MATCH_BITS, 16 * 1024 * 1024);
  
  	/*
  	 * See if the PCI bus has been configured by the firmware.
  	 */
  	reg = __raw_readq(IOADDR(A_SCD_SYSTEM_CFG));
  	if (!(reg & M_SYS_PCI_HOST)) {
  		sb1250_bus_status |= PCI_DEVICE_MODE;
  	} else {
  		cmdreg =
  		    READCFG32(CFGOFFSET
  			      (0, PCI_DEVFN(PCI_BRIDGE_DEVICE, 0),
  			       PCI_COMMAND));
  		if (!(cmdreg & PCI_COMMAND_MASTER)) {
  			printk
  			    ("PCI: Skipping PCI probe.	Bus is not initialized.
  ");
  			iounmap(cfg_space);
  			return 0;
  		}
  		sb1250_bus_status |= PCI_BUS_ENABLED;
  	}
  
  	/*
  	 * Establish mappings in KSEG2 (kernel virtual) to PCI I/O
  	 * space.  Use "match bytes" policy to make everything look
  	 * little-endian.  So, you need to also set
  	 * CONFIG_SWAP_IO_SPACE, but this is the combination that
  	 * works correctly with most of Linux's drivers.
  	 * XXX ehs: Should this happen in PCI Device mode?
  	 */
  	io_map_base = ioremap(A_PHYS_LDTPCI_IO_MATCH_BYTES, 1024 * 1024);
  	sb1250_controller.io_map_base = (unsigned long)io_map_base;
  	set_io_port_base((unsigned long)io_map_base);
  
  #ifdef CONFIG_SIBYTE_HAS_LDT
  	/*
  	 * Also check the LDT bridge's enable, just in case we didn't
  	 * initialize that one.
  	 */
  
  	cmdreg = READCFG32(CFGOFFSET(0, PCI_DEVFN(LDT_BRIDGE_DEVICE, 0),
  				     PCI_COMMAND));
  	if (cmdreg & PCI_COMMAND_MASTER) {
  		sb1250_bus_status |= LDT_BUS_ENABLED;
  
  		/*
  		 * Need bits 23:16 to convey vector number.  Note that
  		 * this consumes 4MB of kernel-mapped memory
  		 * (Kseg2/Kseg3) for 32-bit kernel.
  		 */
  		ldt_eoi_space = (unsigned long)
  		    ioremap(A_PHYS_LDT_SPECIAL_MATCH_BYTES,
  			    4 * 1024 * 1024);
  	}
  #endif
  
  	register_pci_controller(&sb1250_controller);
  
  #ifdef CONFIG_VGA_CONSOLE
  	console_lock();
  	do_take_over_console(&vga_con, 0, MAX_NR_CONSOLES - 1, 1);
  	console_unlock();
  #endif
  	return 0;
  }
  arch_initcall(sb1250_pcibios_init);