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iommu.c

/*
 * Copyright (C) 2005-2007, PA Semi, Inc
 *
 * Maintained by: Olof Johansson <olof@lixom.net>
 *
 * 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
 */

#undef DEBUG

#include <linux/types.h>
#include <linux/spinlock.h>
#include <linux/pci.h>
#include <asm/iommu.h>
#include <asm/machdep.h>
#include <asm/abs_addr.h>
#include <asm/firmware.h>


#define IOBMAP_PAGE_SHIFT     12
#define IOBMAP_PAGE_SIZE      (1 << IOBMAP_PAGE_SHIFT)
#define IOBMAP_PAGE_MASK      (IOBMAP_PAGE_SIZE - 1)

#define IOB_BASE        0xe0000000
#define IOB_SIZE        0x3000
/* Configuration registers */
#define IOBCAP_REG            0x10
#define IOBCOM_REG            0x40
/* Enable IOB address translation */
#define IOBCOM_ATEN           0x00000100

/* Address decode configuration register */
#define IOB_AD_REG            0x53
/* IOBCOM_AD_REG fields */
#define IOB_AD_VGPRT          0x00000e00
#define IOB_AD_VGAEN          0x00000100
/* Direct mapping settings */
#define IOB_AD_MPSEL_MASK     0x00000030
#define IOB_AD_MPSEL_B38      0x00000000
#define IOB_AD_MPSEL_B40      0x00000010
#define IOB_AD_MPSEL_B42      0x00000020
/* Translation window size / enable */
#define IOB_AD_TRNG_MASK      0x00000003
#define IOB_AD_TRNG_256M      0x00000000
#define IOB_AD_TRNG_2G        0x00000001
#define IOB_AD_TRNG_128G      0x00000003

#define IOB_TABLEBASE_REG     0x55

/* Base of the 64 4-byte L1 registers */
#define IOB_XLT_L1_REGBASE    0xac0

/* Register to invalidate TLB entries */
#define IOB_AT_INVAL_TLB_REG  0xb40

/* The top two bits of the level 1 entry contains valid and type flags */
#define IOBMAP_L1E_V          0x40000000
#define IOBMAP_L1E_V_B        0x80000000

/* For big page entries, the bottom two bits contains flags */
#define IOBMAP_L1E_BIG_CACHED 0x00000002
#define IOBMAP_L1E_BIG_PRIORITY     0x00000001

/* For regular level 2 entries, top 2 bits contain valid and cache flags */
#define IOBMAP_L2E_V          0x80000000
#define IOBMAP_L2E_V_CACHED   0xc0000000

static u32 __iomem *iob;
static u32 iob_l1_emptyval;
static u32 iob_l2_emptyval;
static u32 *iob_l2_base;

static struct iommu_table iommu_table_iobmap;
static int iommu_table_iobmap_inited;

static void iobmap_build(struct iommu_table *tbl, long index,
                   long npages, unsigned long uaddr,
                   enum dma_data_direction direction)
{
      u32 *ip;
      u32 rpn;
      unsigned long bus_addr;

      pr_debug("iobmap: build at: %lx, %lx, addr: %lx\n", index, npages, uaddr);

      bus_addr = (tbl->it_offset + index) << IOBMAP_PAGE_SHIFT;

      ip = ((u32 *)tbl->it_base) + index;

      while (npages--) {
            rpn = virt_to_abs(uaddr) >> IOBMAP_PAGE_SHIFT;

            *(ip++) = IOBMAP_L2E_V | rpn;
            /* invalidate tlb, can be optimized more */
            out_le32(iob+IOB_AT_INVAL_TLB_REG, bus_addr >> 14);

            uaddr += IOBMAP_PAGE_SIZE;
            bus_addr += IOBMAP_PAGE_SIZE;
      }
}


static void iobmap_free(struct iommu_table *tbl, long index,
                  long npages)
{
      u32 *ip;
      unsigned long bus_addr;

      pr_debug("iobmap: free at: %lx, %lx\n", index, npages);

      bus_addr = (tbl->it_offset + index) << IOBMAP_PAGE_SHIFT;

      ip = ((u32 *)tbl->it_base) + index;

      while (npages--) {
            *(ip++) = iob_l2_emptyval;
            /* invalidate tlb, can be optimized more */
            out_le32(iob+IOB_AT_INVAL_TLB_REG, bus_addr >> 14);
            bus_addr += IOBMAP_PAGE_SIZE;
      }
}


static void iommu_table_iobmap_setup(void)
{
      pr_debug(" -> %s\n", __func__);
      iommu_table_iobmap.it_busno = 0;
      iommu_table_iobmap.it_offset = 0;
      /* it_size is in number of entries */
      iommu_table_iobmap.it_size = 0x80000000 >> IOBMAP_PAGE_SHIFT;

      /* Initialize the common IOMMU code */
      iommu_table_iobmap.it_base = (unsigned long)iob_l2_base;
      iommu_table_iobmap.it_index = 0;
      /* XXXOJN tune this to avoid IOB cache invals.
       * Should probably be 8 (64 bytes)
       */
      iommu_table_iobmap.it_blocksize = 4;
      iommu_init_table(&iommu_table_iobmap, 0);
      pr_debug(" <- %s\n", __func__);
}



static void pci_dma_bus_setup_pasemi(struct pci_bus *bus)
{
      struct device_node *dn;

      pr_debug("pci_dma_bus_setup, bus %p, bus->self %p\n", bus, bus->self);

      if (!iommu_table_iobmap_inited) {
            iommu_table_iobmap_inited = 1;
            iommu_table_iobmap_setup();
      }

      dn = pci_bus_to_OF_node(bus);

      if (dn)
            PCI_DN(dn)->iommu_table = &iommu_table_iobmap;

}


static void pci_dma_dev_setup_pasemi(struct pci_dev *dev)
{
      pr_debug("pci_dma_dev_setup, dev %p (%s)\n", dev, pci_name(dev));

#if !defined(CONFIG_PPC_PASEMI_IOMMU_DMA_FORCE)
      /* For non-LPAR environment, don't translate anything for the DMA
       * engine. The exception to this is if the user has enabled
       * CONFIG_PPC_PASEMI_IOMMU_DMA_FORCE at build time.
       */
      if (dev->vendor == 0x1959 && dev->device == 0xa007 &&
          !firmware_has_feature(FW_FEATURE_LPAR))
            dev->dev.archdata.dma_ops = &dma_direct_ops;
#endif

      dev->dev.archdata.dma_data = &iommu_table_iobmap;
}

static void pci_dma_bus_setup_null(struct pci_bus *b) { }
static void pci_dma_dev_setup_null(struct pci_dev *d) { }

int __init iob_init(struct device_node *dn)
{
      unsigned long tmp;
      u32 regword;
      int i;

      pr_debug(" -> %s\n", __func__);

      /* Allocate a spare page to map all invalid IOTLB pages. */
      tmp = lmb_alloc(IOBMAP_PAGE_SIZE, IOBMAP_PAGE_SIZE);
      if (!tmp)
            panic("IOBMAP: Cannot allocate spare page!");
      /* Empty l1 is marked invalid */
      iob_l1_emptyval = 0;
      /* Empty l2 is mapped to dummy page */
      iob_l2_emptyval = IOBMAP_L2E_V | (tmp >> IOBMAP_PAGE_SHIFT);

      iob = ioremap(IOB_BASE, IOB_SIZE);
      if (!iob)
            panic("IOBMAP: Cannot map registers!");

      /* setup direct mapping of the L1 entries */
      for (i = 0; i < 64; i++) {
            /* Each L1 covers 32MB, i.e. 8K entries = 32K of ram */
            regword = IOBMAP_L1E_V | (__pa(iob_l2_base + i*0x2000) >> 12);
            out_le32(iob+IOB_XLT_L1_REGBASE+i, regword);
      }

      /* set 2GB translation window, based at 0 */
      regword = in_le32(iob+IOB_AD_REG);
      regword &= ~IOB_AD_TRNG_MASK;
      regword |= IOB_AD_TRNG_2G;
      out_le32(iob+IOB_AD_REG, regword);

      /* Enable translation */
      regword = in_le32(iob+IOBCOM_REG);
      regword |= IOBCOM_ATEN;
      out_le32(iob+IOBCOM_REG, regword);

      pr_debug(" <- %s\n", __func__);

      return 0;
}


/* These are called very early. */
void __init iommu_init_early_pasemi(void)
{
      int iommu_off;

#ifndef CONFIG_PPC_PASEMI_IOMMU
      iommu_off = 1;
#else
      iommu_off = of_chosen &&
                  of_get_property(of_chosen, "linux,iommu-off", NULL);
#endif
      if (iommu_off) {
            /* Direct I/O, IOMMU off */
            ppc_md.pci_dma_dev_setup = pci_dma_dev_setup_null;
            ppc_md.pci_dma_bus_setup = pci_dma_bus_setup_null;
            set_pci_dma_ops(&dma_direct_ops);

            return;
      }

      iob_init(NULL);

      ppc_md.pci_dma_dev_setup = pci_dma_dev_setup_pasemi;
      ppc_md.pci_dma_bus_setup = pci_dma_bus_setup_pasemi;
      ppc_md.tce_build = iobmap_build;
      ppc_md.tce_free  = iobmap_free;
      set_pci_dma_ops(&dma_iommu_ops);
}

void __init alloc_iobmap_l2(void)
{
#ifndef CONFIG_PPC_PASEMI_IOMMU
      return;
#endif
      /* For 2G space, 8x64 pages (2^21 bytes) is max total l2 size */
      iob_l2_base = (u32 *)abs_to_virt(lmb_alloc_base(1UL<<21, 1UL<<21, 0x80000000));

      printk(KERN_INFO "IOBMAP L2 allocated at: %p\n", iob_l2_base);
}

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