/*
   * arch/x86/pci/sta2x11-fixup.c
   * glue code for lib/swiotlb.c and DMA translation between STA2x11
   * AMBA memory mapping and the X86 memory mapping
   *
   * ST Microelectronics ConneXt (STA2X11/STA2X10)
   *
   * Copyright (c) 2010-2011 Wind River Systems, Inc.
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License version 2 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
   *
   */
  
  #include <linux/pci.h>
  #include <linux/pci_ids.h>
  #include <linux/export.h>
  #include <linux/list.h>
  
  #define STA2X11_SWIOTLB_SIZE (4*1024*1024)
  extern int swiotlb_late_init_with_default_size(size_t default_size);
  
  /*
   * We build a list of bus numbers that are under the ConneXt. The
   * main bridge hosts 4 busses, which are the 4 endpoints, in order.
   */
  #define STA2X11_NR_EP		4	/* 0..3 included */
  #define STA2X11_NR_FUNCS	8	/* 0..7 included */
  #define STA2X11_AMBA_SIZE	(512 << 20)
  
  struct sta2x11_ahb_regs { /* saved during suspend */
  	u32 base, pexlbase, pexhbase, crw;
  };
  
  struct sta2x11_mapping {
  	u32 amba_base;
  	int is_suspended;
  	struct sta2x11_ahb_regs regs[STA2X11_NR_FUNCS];
  };
  
  struct sta2x11_instance {
  	struct list_head list;
  	int bus0;
  	struct sta2x11_mapping map[STA2X11_NR_EP];
  };
  
  static LIST_HEAD(sta2x11_instance_list);
  
  /* At probe time, record new instances of this bridge (likely one only) */
  static void sta2x11_new_instance(struct pci_dev *pdev)
  {
  	struct sta2x11_instance *instance;
  
  	instance = kzalloc(sizeof(*instance), GFP_ATOMIC);
  	if (!instance)
  		return;
  	/* This has a subordinate bridge, with 4 more-subordinate ones */
  	instance->bus0 = pdev->subordinate->number + 1;
  
  	if (list_empty(&sta2x11_instance_list)) {
  		int size = STA2X11_SWIOTLB_SIZE;
  		/* First instance: register your own swiotlb area */
  		dev_info(&pdev->dev, "Using SWIOTLB (size %i)
  ", size);
  		if (swiotlb_late_init_with_default_size(size))
  			dev_emerg(&pdev->dev, "init swiotlb failed
  ");
  	}
  	list_add(&instance->list, &sta2x11_instance_list);
  }
  DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, 0xcc17, sta2x11_new_instance);
  
  /*
   * Utility functions used in this file from below
   */
  static struct sta2x11_instance *sta2x11_pdev_to_instance(struct pci_dev *pdev)
  {
  	struct sta2x11_instance *instance;
  	int ep;
  
  	list_for_each_entry(instance, &sta2x11_instance_list, list) {
  		ep = pdev->bus->number - instance->bus0;
  		if (ep >= 0 && ep < STA2X11_NR_EP)
  			return instance;
  	}
  	return NULL;
  }
  
  static int sta2x11_pdev_to_ep(struct pci_dev *pdev)
  {
  	struct sta2x11_instance *instance;
  
  	instance = sta2x11_pdev_to_instance(pdev);
  	if (!instance)
  		return -1;
  
  	return pdev->bus->number - instance->bus0;
  }
  
  static struct sta2x11_mapping *sta2x11_pdev_to_mapping(struct pci_dev *pdev)
  {
  	struct sta2x11_instance *instance;
  	int ep;
  
  	instance = sta2x11_pdev_to_instance(pdev);
  	if (!instance)
  		return NULL;
  	ep = sta2x11_pdev_to_ep(pdev);
  	return instance->map + ep;
  }
  
  /* This is exported, as some devices need to access the MFD registers */
  struct sta2x11_instance *sta2x11_get_instance(struct pci_dev *pdev)
  {
  	return sta2x11_pdev_to_instance(pdev);
  }
  EXPORT_SYMBOL(sta2x11_get_instance);
  
  
  /**
   * p2a - Translate physical address to STA2x11 AMBA address,
   *       used for DMA transfers to STA2x11
   * @p: Physical address
   * @pdev: PCI device (must be hosted within the connext)
   */
  static dma_addr_t p2a(dma_addr_t p, struct pci_dev *pdev)
  {
  	struct sta2x11_mapping *map;
  	dma_addr_t a;
  
  	map = sta2x11_pdev_to_mapping(pdev);
  	a = p + map->amba_base;
  	return a;
  }
  
  /**
   * a2p - Translate STA2x11 AMBA address to physical address
   *       used for DMA transfers from STA2x11
   * @a: STA2x11 AMBA address
   * @pdev: PCI device (must be hosted within the connext)
   */
  static dma_addr_t a2p(dma_addr_t a, struct pci_dev *pdev)
  {
  	struct sta2x11_mapping *map;
  	dma_addr_t p;
  
  	map = sta2x11_pdev_to_mapping(pdev);
  	p = a - map->amba_base;
  	return p;
  }
  
  /**
   * sta2x11_swiotlb_alloc_coherent - Allocate swiotlb bounce buffers
   *     returns virtual address. This is the only "special" function here.
   * @dev: PCI device
   * @size: Size of the buffer
   * @dma_handle: DMA address
   * @flags: memory flags
   */
  static void *sta2x11_swiotlb_alloc_coherent(struct device *dev,
  					    size_t size,
  					    dma_addr_t *dma_handle,
  					    gfp_t flags,
  					    struct dma_attrs *attrs)
  {
  	void *vaddr;
  
  	vaddr = dma_generic_alloc_coherent(dev, size, dma_handle, flags, attrs);
  	if (!vaddr)
  		vaddr = swiotlb_alloc_coherent(dev, size, dma_handle, flags);
  	*dma_handle = p2a(*dma_handle, to_pci_dev(dev));
  	return vaddr;
  }
  
  /* We have our own dma_ops: the same as swiotlb but from alloc (above) */
  static struct dma_map_ops sta2x11_dma_ops = {
  	.alloc = sta2x11_swiotlb_alloc_coherent,
  	.free = swiotlb_free_coherent,
  	.map_page = swiotlb_map_page,
  	.unmap_page = swiotlb_unmap_page,
  	.map_sg = swiotlb_map_sg_attrs,
  	.unmap_sg = swiotlb_unmap_sg_attrs,
  	.sync_single_for_cpu = swiotlb_sync_single_for_cpu,
  	.sync_single_for_device = swiotlb_sync_single_for_device,
  	.sync_sg_for_cpu = swiotlb_sync_sg_for_cpu,
  	.sync_sg_for_device = swiotlb_sync_sg_for_device,
  	.mapping_error = swiotlb_dma_mapping_error,
  	.dma_supported = NULL, /* FIXME: we should use this instead! */
  };
  
  /* At setup time, we use our own ops if the device is a ConneXt one */
  static void sta2x11_setup_pdev(struct pci_dev *pdev)
  {
  	struct sta2x11_instance *instance = sta2x11_pdev_to_instance(pdev);
  
  	if (!instance) /* either a sta2x11 bridge or another ST device */
  		return;
  	pci_set_consistent_dma_mask(pdev, STA2X11_AMBA_SIZE - 1);
  	pci_set_dma_mask(pdev, STA2X11_AMBA_SIZE - 1);
  	pdev->dev.archdata.dma_ops = &sta2x11_dma_ops;
  
  	/* We must enable all devices as master, for audio DMA to work */
  	pci_set_master(pdev);
  }
  DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, sta2x11_setup_pdev);
  
  /*
   * The following three functions are exported (used in swiotlb: FIXME)
   */
  /**
   * dma_capable - Check if device can manage DMA transfers (FIXME: kill it)
   * @dev: device for a PCI device
   * @addr: DMA address
   * @size: DMA size
   */
  bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
  {
  	struct sta2x11_mapping *map;
  
  	if (dev->archdata.dma_ops != &sta2x11_dma_ops) {
  		if (!dev->dma_mask)
  			return false;
  		return addr + size - 1 <= *dev->dma_mask;
  	}
  
  	map = sta2x11_pdev_to_mapping(to_pci_dev(dev));
  
  	if (!map || (addr < map->amba_base))
  		return false;
  	if (addr + size >= map->amba_base + STA2X11_AMBA_SIZE) {
  		return false;
  	}
  
  	return true;
  }
  
  /**
   * phys_to_dma - Return the DMA AMBA address used for this STA2x11 device
   * @dev: device for a PCI device
   * @paddr: Physical address
   */
  dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
  {
  	if (dev->archdata.dma_ops != &sta2x11_dma_ops)
  		return paddr;
  	return p2a(paddr, to_pci_dev(dev));
  }
  
  /**
   * dma_to_phys - Return the physical address used for this STA2x11 DMA address
   * @dev: device for a PCI device
   * @daddr: STA2x11 AMBA DMA address
   */
  phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
  {
  	if (dev->archdata.dma_ops != &sta2x11_dma_ops)
  		return daddr;
  	return a2p(daddr, to_pci_dev(dev));
  }
  
  
  /*
   * At boot we must set up the mappings for the pcie-to-amba bridge.
   * It involves device access, and the same happens at suspend/resume time
   */
  
  #define AHB_MAPB		0xCA4
  #define AHB_CRW(i)		(AHB_MAPB + 0  + (i) * 0x10)
  #define AHB_CRW_SZMASK			0xfffffc00UL
  #define AHB_CRW_ENABLE			(1 << 0)
  #define AHB_CRW_WTYPE_MEM		(2 << 1)
  #define AHB_CRW_ROE			(1UL << 3)	/* Relax Order Ena */
  #define AHB_CRW_NSE			(1UL << 4)	/* No Snoop Enable */
  #define AHB_BASE(i)		(AHB_MAPB + 4  + (i) * 0x10)
  #define AHB_PEXLBASE(i)		(AHB_MAPB + 8  + (i) * 0x10)
  #define AHB_PEXHBASE(i)		(AHB_MAPB + 12 + (i) * 0x10)
  
  /* At probe time, enable mapping for each endpoint, using the pdev */
  static void sta2x11_map_ep(struct pci_dev *pdev)
  {
  	struct sta2x11_mapping *map = sta2x11_pdev_to_mapping(pdev);
  	int i;
  
  	if (!map)
  		return;
  	pci_read_config_dword(pdev, AHB_BASE(0), &map->amba_base);
  
  	/* Configure AHB mapping */
  	pci_write_config_dword(pdev, AHB_PEXLBASE(0), 0);
  	pci_write_config_dword(pdev, AHB_PEXHBASE(0), 0);
  	pci_write_config_dword(pdev, AHB_CRW(0), STA2X11_AMBA_SIZE |
  			       AHB_CRW_WTYPE_MEM | AHB_CRW_ENABLE);
  
  	/* Disable all the other windows */
  	for (i = 1; i < STA2X11_NR_FUNCS; i++)
  		pci_write_config_dword(pdev, AHB_CRW(i), 0);
  
  	dev_info(&pdev->dev,
  		 "sta2x11: Map EP %i: AMBA address %#8x-%#8x
  ",
  		 sta2x11_pdev_to_ep(pdev),  map->amba_base,
  		 map->amba_base + STA2X11_AMBA_SIZE - 1);
  }
  DECLARE_PCI_FIXUP_ENABLE(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, sta2x11_map_ep);
  
  #ifdef CONFIG_PM /* Some register values must be saved and restored */
  
  static void suspend_mapping(struct pci_dev *pdev)
  {
  	struct sta2x11_mapping *map = sta2x11_pdev_to_mapping(pdev);
  	int i;
  
  	if (!map)
  		return;
  
  	if (map->is_suspended)
  		return;
  	map->is_suspended = 1;
  
  	/* Save all window configs */
  	for (i = 0; i < STA2X11_NR_FUNCS; i++) {
  		struct sta2x11_ahb_regs *regs = map->regs + i;
  
  		pci_read_config_dword(pdev, AHB_BASE(i), &regs->base);
  		pci_read_config_dword(pdev, AHB_PEXLBASE(i), &regs->pexlbase);
  		pci_read_config_dword(pdev, AHB_PEXHBASE(i), &regs->pexhbase);
  		pci_read_config_dword(pdev, AHB_CRW(i), &regs->crw);
  	}
  }
  DECLARE_PCI_FIXUP_SUSPEND(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, suspend_mapping);
  
  static void resume_mapping(struct pci_dev *pdev)
  {
  	struct sta2x11_mapping *map = sta2x11_pdev_to_mapping(pdev);
  	int i;
  
  	if (!map)
  		return;
  
  
  	if (!map->is_suspended)
  		goto out;
  	map->is_suspended = 0;
  
  	/* Restore all window configs */
  	for (i = 0; i < STA2X11_NR_FUNCS; i++) {
  		struct sta2x11_ahb_regs *regs = map->regs + i;
  
  		pci_write_config_dword(pdev, AHB_BASE(i), regs->base);
  		pci_write_config_dword(pdev, AHB_PEXLBASE(i), regs->pexlbase);
  		pci_write_config_dword(pdev, AHB_PEXHBASE(i), regs->pexhbase);
  		pci_write_config_dword(pdev, AHB_CRW(i), regs->crw);
  	}
  out:
  	pci_set_master(pdev); /* Like at boot, enable master on all devices */
  }
  DECLARE_PCI_FIXUP_RESUME(PCI_VENDOR_ID_STMICRO, PCI_ANY_ID, resume_mapping);
  
  #endif /* CONFIG_PM */