/*
   * init_ohci1394_dma.c - Initializes physical DMA on all OHCI 1394 controllers
   *
   * Copyright (C) 2006-2007      Bernhard Kaindl <bk@suse.de>
   *
   * Derived from drivers/ieee1394/ohci1394.c and arch/x86/kernel/early-quirks.c
   * this file has functions to:
   * - scan the PCI very early on boot for all OHCI 1394-compliant controllers
   * - reset and initialize them and make them join the IEEE1394 bus and
   * - enable physical DMA on them to allow remote debugging
   *
   * All code and data is marked as __init and __initdata, respective as
   * during boot, all OHCI1394 controllers may be claimed by the firewire
   * stack and at this point, this code should not touch them anymore.
   *
   * To use physical DMA after the initialization of the firewire stack,
   * be sure that the stack enables it and (re-)attach after the bus reset
   * which may be caused by the firewire stack initialization.
   *
   * 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.
   */
  
  #include <linux/delay.h>
  #include <linux/io.h>
  #include <linux/kernel.h>
  #include <linux/pci.h>		/* for PCI defines */
  #include <linux/string.h>
  
  #include <asm/pci-direct.h>	/* for direct PCI config space access */
  #include <asm/fixmap.h>
  
  #include <linux/init_ohci1394_dma.h>
  #include "ohci.h"
  
  int __initdata init_ohci1394_dma_early;
  
  struct ohci {
  	void __iomem *registers;
  };
  
  static inline void reg_write(const struct ohci *ohci, int offset, u32 data)
  {
  	writel(data, ohci->registers + offset);
  }
  
  static inline u32 reg_read(const struct ohci *ohci, int offset)
  {
  	return readl(ohci->registers + offset);
  }
  
  #define OHCI_LOOP_COUNT		100	/* Number of loops for reg read waits */
  
  /* Reads a PHY register of an OHCI-1394 controller */
  static inline u8 __init get_phy_reg(struct ohci *ohci, u8 addr)
  {
  	int i;
  	u32 r;
  
  	reg_write(ohci, OHCI1394_PhyControl, (addr << 8) | 0x00008000);
  
  	for (i = 0; i < OHCI_LOOP_COUNT; i++) {
  		if (reg_read(ohci, OHCI1394_PhyControl) & 0x80000000)
  			break;
  		mdelay(1);
  	}
  	r = reg_read(ohci, OHCI1394_PhyControl);
  
  	return (r & 0x00ff0000) >> 16;
  }
  
  /* Writes to a PHY register of an OHCI-1394 controller */
  static inline void __init set_phy_reg(struct ohci *ohci, u8 addr, u8 data)
  {
  	int i;
  
  	reg_write(ohci, OHCI1394_PhyControl, (addr << 8) | data | 0x00004000);
  
  	for (i = 0; i < OHCI_LOOP_COUNT; i++) {
  		if (!(reg_read(ohci, OHCI1394_PhyControl) & 0x00004000))
  			break;
  		mdelay(1);
  	}
  }
  
  /* Resets an OHCI-1394 controller (for sane state before initialization) */
  static inline void __init init_ohci1394_soft_reset(struct ohci *ohci)
  {
  	int i;
  
  	reg_write(ohci, OHCI1394_HCControlSet, OHCI1394_HCControl_softReset);
  
  	for (i = 0; i < OHCI_LOOP_COUNT; i++) {
  		if (!(reg_read(ohci, OHCI1394_HCControlSet)
  				   & OHCI1394_HCControl_softReset))
  			break;
  		mdelay(1);
  	}
  }
  
  #define OHCI1394_MAX_AT_REQ_RETRIES	0xf
  #define OHCI1394_MAX_AT_RESP_RETRIES	0x2
  #define OHCI1394_MAX_PHYS_RESP_RETRIES	0x8
  
  /* Basic OHCI-1394 register and port inititalization */
  static inline void __init init_ohci1394_initialize(struct ohci *ohci)
  {
  	u32 bus_options;
  	int num_ports, i;
  
  	/* Put some defaults to these undefined bus options */
  	bus_options = reg_read(ohci, OHCI1394_BusOptions);
  	bus_options |=  0x60000000; /* Enable CMC and ISC */
  	bus_options &= ~0x00ff0000; /* XXX: Set cyc_clk_acc to zero for now */
  	bus_options &= ~0x18000000; /* Disable PMC and BMC */
  	reg_write(ohci, OHCI1394_BusOptions, bus_options);
  
  	/* Set the bus number */
  	reg_write(ohci, OHCI1394_NodeID, 0x0000ffc0);
  
  	/* Enable posted writes */
  	reg_write(ohci, OHCI1394_HCControlSet,
  			OHCI1394_HCControl_postedWriteEnable);
  
  	/* Clear link control register */
  	reg_write(ohci, OHCI1394_LinkControlClear, 0xffffffff);
  
  	/* enable phys */
  	reg_write(ohci, OHCI1394_LinkControlSet,
  			OHCI1394_LinkControl_rcvPhyPkt);
  
  	/* Don't accept phy packets into AR request context */
  	reg_write(ohci, OHCI1394_LinkControlClear, 0x00000400);
  
  	/* Clear the Isochonouys interrupt masks */
  	reg_write(ohci, OHCI1394_IsoRecvIntMaskClear, 0xffffffff);
  	reg_write(ohci, OHCI1394_IsoRecvIntEventClear, 0xffffffff);
  	reg_write(ohci, OHCI1394_IsoXmitIntMaskClear, 0xffffffff);
  	reg_write(ohci, OHCI1394_IsoXmitIntEventClear, 0xffffffff);
  
  	/* Accept asynchronous transfer requests from all nodes for now */
  	reg_write(ohci, OHCI1394_AsReqFilterHiSet, 0x80000000);
  
  	/* Specify asynchronous transfer retries */
  	reg_write(ohci, OHCI1394_ATRetries,
  		  OHCI1394_MAX_AT_REQ_RETRIES |
  		  (OHCI1394_MAX_AT_RESP_RETRIES<<4) |
  		  (OHCI1394_MAX_PHYS_RESP_RETRIES<<8));
  
  	/* We don't want hardware swapping */
  	reg_write(ohci, OHCI1394_HCControlClear,
  		  OHCI1394_HCControl_noByteSwapData);
  
  	/* Enable link */
  	reg_write(ohci, OHCI1394_HCControlSet, OHCI1394_HCControl_linkEnable);
  
  	/* If anything is connected to a port, make sure it is enabled */
  	num_ports = get_phy_reg(ohci, 2) & 0xf;
  	for (i = 0; i < num_ports; i++) {
  		unsigned int status;
  
  		set_phy_reg(ohci, 7, i);
  		status = get_phy_reg(ohci, 8);
  
  		if (status & 0x20)
  			set_phy_reg(ohci, 8, status & ~1);
  	}
  }
  
  /**
   * init_ohci1394_wait_for_busresets - wait until bus resets are completed
   *
   * OHCI1394 initialization itself and any device going on- or offline
   * and any cable issue cause a IEEE1394 bus reset. The OHCI1394 spec
   * specifies that physical DMA is disabled on each bus reset and it
   * has to be enabled after each bus reset when needed. We resort
   * to polling here because on early boot, we have no interrupts.
   */
  static inline void __init init_ohci1394_wait_for_busresets(struct ohci *ohci)
  {
  	int i, events;
  
  	for (i = 0; i < 9; i++) {
  		mdelay(200);
  		events = reg_read(ohci, OHCI1394_IntEventSet);
  		if (events & OHCI1394_busReset)
  			reg_write(ohci, OHCI1394_IntEventClear,
  					OHCI1394_busReset);
  	}
  }
  
  /**
   * init_ohci1394_enable_physical_dma - Enable physical DMA for remote debugging
   * This enables remote DMA access over IEEE1394 from every host for the low
   * 4GB of address space. DMA accesses above 4GB are not available currently.
   */
  static inline void __init init_ohci1394_enable_physical_dma(struct ohci *ohci)
  {
  	reg_write(ohci, OHCI1394_PhyReqFilterHiSet, 0xffffffff);
  	reg_write(ohci, OHCI1394_PhyReqFilterLoSet, 0xffffffff);
  	reg_write(ohci, OHCI1394_PhyUpperBound, 0xffff0000);
  }
  
  /**
   * init_ohci1394_reset_and_init_dma - init controller and enable DMA
   * This initializes the given controller and enables physical DMA engine in it.
   */
  static inline void __init init_ohci1394_reset_and_init_dma(struct ohci *ohci)
  {
  	/* Start off with a soft reset, clears everything to a sane state. */
  	init_ohci1394_soft_reset(ohci);
  
  	/* Accessing some registers without LPS enabled may cause lock up */
  	reg_write(ohci, OHCI1394_HCControlSet, OHCI1394_HCControl_LPS);
  
  	/* Disable and clear interrupts */
  	reg_write(ohci, OHCI1394_IntEventClear, 0xffffffff);
  	reg_write(ohci, OHCI1394_IntMaskClear, 0xffffffff);
  
  	mdelay(50); /* Wait 50msec to make sure we have full link enabled */
  
  	init_ohci1394_initialize(ohci);
  	/*
  	 * The initialization causes at least one IEEE1394 bus reset. Enabling
  	 * physical DMA only works *after* *all* bus resets have calmed down:
  	 */
  	init_ohci1394_wait_for_busresets(ohci);
  
  	/* We had to wait and do this now if we want to debug early problems */
  	init_ohci1394_enable_physical_dma(ohci);
  }
  
  /**
   * init_ohci1394_controller - Map the registers of the controller and init DMA
   * This maps the registers of the specified controller and initializes it
   */
  static inline void __init init_ohci1394_controller(int num, int slot, int func)
  {
  	unsigned long ohci_base;
  	struct ohci ohci;
  
  	printk(KERN_INFO "init_ohci1394_dma: initializing OHCI-1394"
  			 " at %02x:%02x.%x
  ", num, slot, func);
  
  	ohci_base = read_pci_config(num, slot, func, PCI_BASE_ADDRESS_0+(0<<2))
  						   & PCI_BASE_ADDRESS_MEM_MASK;
  
  	set_fixmap_nocache(FIX_OHCI1394_BASE, ohci_base);
  
  	ohci.registers = (void __iomem *)fix_to_virt(FIX_OHCI1394_BASE);
  
  	init_ohci1394_reset_and_init_dma(&ohci);
  }
  
  /**
   * debug_init_ohci1394_dma - scan for OHCI1394 controllers and init DMA on them
   * Scans the whole PCI space for OHCI1394 controllers and inits DMA on them
   */
  void __init init_ohci1394_dma_on_all_controllers(void)
  {
  	int num, slot, func;
  	u32 class;
  
  	if (!early_pci_allowed())
  		return;
  
  	/* Poor man's PCI discovery, the only thing we can do at early boot */
  	for (num = 0; num < 32; num++) {
  		for (slot = 0; slot < 32; slot++) {
  			for (func = 0; func < 8; func++) {
  				class = read_pci_config(num, slot, func,
  							PCI_CLASS_REVISION);
  				if (class == 0xffffffff)
  					continue; /* No device at this func */
  
  				if (class>>8 != PCI_CLASS_SERIAL_FIREWIRE_OHCI)
  					continue; /* Not an OHCI-1394 device */
  
  				init_ohci1394_controller(num, slot, func);
  				break; /* Assume one controller per device */
  			}
  		}
  	}
  	printk(KERN_INFO "init_ohci1394_dma: finished initializing OHCI DMA
  ");
  }
  
  /**
   * setup_init_ohci1394_early - enables early OHCI1394 DMA initialization
   */
  static int __init setup_ohci1394_dma(char *opt)
  {
  	if (!strcmp(opt, "early"))
  		init_ohci1394_dma_early = 1;
  	return 0;
  }
  
  /* passing ohci1394_dma=early on boot causes early OHCI1394 DMA initialization */
  early_param("ohci1394_dma", setup_ohci1394_dma);