common-pci.c

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/*
 * arch/arm/mach-ixp4xx/common-pci.c 
 *
 * IXP4XX PCI routines for all platforms
 *
 * Maintainer: Deepak Saxena <[email protected]>
 *
 * Copyright (C) 2002 Intel Corporation.
 * Copyright (C) 2003 Greg Ungerer <[email protected]>
 * Copyright (C) 2003-2004 MontaVista Software, 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.
 *
 */

#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/ioport.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/export.h>
#include <asm/dma-mapping.h>

#include <asm/cputype.h>
#include <asm/irq.h>
#include <asm/sizes.h>
#include <asm/mach/pci.h>
#include <mach/hardware.h>


/*
 * IXP4xx PCI read function is dependent on whether we are 
 * running A0 or B0 (AppleGate) silicon.
 */
int (*ixp4xx_pci_read)(u32 addr, u32 cmd, u32* data);

/*
 * Base address for PCI regsiter region
 */
unsigned long ixp4xx_pci_reg_base = 0;

/*
 * PCI cfg an I/O routines are done by programming a 
 * command/byte enable register, and then read/writing
 * the data from a data regsiter. We need to ensure
 * these transactions are atomic or we will end up
 * with corrupt data on the bus or in a driver.
 */
static DEFINE_RAW_SPINLOCK(ixp4xx_pci_lock);

/*
 * Read from PCI config space
 */
static void crp_read(u32 ad_cbe, u32 *data)
{
    unsigned long flags;
    raw_spin_lock_irqsave(&ixp4xx_pci_lock, flags);
    *PCI_CRP_AD_CBE = ad_cbe;
    *data = *PCI_CRP_RDATA;
    raw_spin_unlock_irqrestore(&ixp4xx_pci_lock, flags);
}

/*
 * Write to PCI config space
 */
static void crp_write(u32 ad_cbe, u32 data)
{ 
    unsigned long flags;
    raw_spin_lock_irqsave(&ixp4xx_pci_lock, flags);
    *PCI_CRP_AD_CBE = CRP_AD_CBE_WRITE | ad_cbe;
    *PCI_CRP_WDATA = data;
    raw_spin_unlock_irqrestore(&ixp4xx_pci_lock, flags);
}

static inline int check_master_abort(void)
{
    /* check Master Abort bit after access */
    unsigned long isr = *PCI_ISR;

    if (isr & PCI_ISR_PFE) {
        /* make sure the Master Abort bit is reset */    
        *PCI_ISR = PCI_ISR_PFE;
        pr_debug("%s failed\n", __func__);
        return 1;
    }

    return 0;
}

int ixp4xx_pci_read_errata(u32 addr, u32 cmd, u32* data)
{
    unsigned long flags;
    int retval = 0;
    int i;

    raw_spin_lock_irqsave(&ixp4xx_pci_lock, flags);

    *PCI_NP_AD = addr;

    /* 
     * PCI workaround  - only works if NP PCI space reads have 
     * no side effects!!! Read 8 times. last one will be good.
     */
    for (i = 0; i < 8; i++) {
        *PCI_NP_CBE = cmd;
        *data = *PCI_NP_RDATA;
        *data = *PCI_NP_RDATA;
    }

    if(check_master_abort())
        retval = 1;

    raw_spin_unlock_irqrestore(&ixp4xx_pci_lock, flags);
    return retval;
}

int ixp4xx_pci_read_no_errata(u32 addr, u32 cmd, u32* data)
{
    unsigned long flags;
    int retval = 0;

    raw_spin_lock_irqsave(&ixp4xx_pci_lock, flags);

    *PCI_NP_AD = addr;

    /* set up and execute the read */    
    *PCI_NP_CBE = cmd;

    /* the result of the read is now in NP_RDATA */
    *data = *PCI_NP_RDATA; 

    if(check_master_abort())
        retval = 1;

    raw_spin_unlock_irqrestore(&ixp4xx_pci_lock, flags);
    return retval;
}

int ixp4xx_pci_write(u32 addr, u32 cmd, u32 data)
{    
    unsigned long flags;
    int retval = 0;

    raw_spin_lock_irqsave(&ixp4xx_pci_lock, flags);

    *PCI_NP_AD = addr;

    /* set up the write */
    *PCI_NP_CBE = cmd;

    /* execute the write by writing to NP_WDATA */
    *PCI_NP_WDATA = data;

    if(check_master_abort())
        retval = 1;

    raw_spin_unlock_irqrestore(&ixp4xx_pci_lock, flags);
    return retval;
}

static u32 ixp4xx_config_addr(u8 bus_num, u16 devfn, int where)
{
    u32 addr;
    if (!bus_num) {
        /* type 0 */
        addr = BIT(32-PCI_SLOT(devfn)) | ((PCI_FUNC(devfn)) << 8) | 
            (where & ~3);   
    } else {
        /* type 1 */
        addr = (bus_num << 16) | ((PCI_SLOT(devfn)) << 11) | 
            ((PCI_FUNC(devfn)) << 8) | (where & ~3) | 1;
    }
    return addr;
}

/*
 * Mask table, bits to mask for quantity of size 1, 2 or 4 bytes.
 * 0 and 3 are not valid indexes...
 */
static u32 bytemask[] = {
    /*0*/   0,
    /*1*/   0xff,
    /*2*/   0xffff,
    /*3*/   0,
    /*4*/   0xffffffff,
};

static u32 local_byte_lane_enable_bits(u32 n, int size)
{
    if (size == 1)
        return (0xf & ~BIT(n)) << CRP_AD_CBE_BESL;
    if (size == 2)
        return (0xf & ~(BIT(n) | BIT(n+1))) << CRP_AD_CBE_BESL;
    if (size == 4)
        return 0;
    return 0xffffffff;
}

static int local_read_config(int where, int size, u32 *value)
{ 
    u32 n, data;
    pr_debug("local_read_config from %d size %d\n", where, size);
    n = where % 4;
    crp_read(where & ~3, &data);
    *value = (data >> (8*n)) & bytemask[size];
    pr_debug("local_read_config read %#x\n", *value);
    return PCIBIOS_SUCCESSFUL;
}

static int local_write_config(int where, int size, u32 value)
{
    u32 n, byte_enables, data;
    pr_debug("local_write_config %#x to %d size %d\n", value, where, size);
    n = where % 4;
    byte_enables = local_byte_lane_enable_bits(n, size);
    if (byte_enables == 0xffffffff)
        return PCIBIOS_BAD_REGISTER_NUMBER;
    data = value << (8*n);
    crp_write((where & ~3) | byte_enables, data);
    return PCIBIOS_SUCCESSFUL;
}

static u32 byte_lane_enable_bits(u32 n, int size)
{
    if (size == 1)
        return (0xf & ~BIT(n)) << 4;
    if (size == 2)
        return (0xf & ~(BIT(n) | BIT(n+1))) << 4;
    if (size == 4)
        return 0;
    return 0xffffffff;
}

static int ixp4xx_pci_read_config(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *value)
{
    u32 n, byte_enables, addr, data;
    u8 bus_num = bus->number;

    pr_debug("read_config from %d size %d dev %d:%d:%d\n", where, size,
        bus_num, PCI_SLOT(devfn), PCI_FUNC(devfn));

    *value = 0xffffffff;
    n = where % 4;
    byte_enables = byte_lane_enable_bits(n, size);
    if (byte_enables == 0xffffffff)
        return PCIBIOS_BAD_REGISTER_NUMBER;

    addr = ixp4xx_config_addr(bus_num, devfn, where);
    if (ixp4xx_pci_read(addr, byte_enables | NP_CMD_CONFIGREAD, &data))
        return PCIBIOS_DEVICE_NOT_FOUND;

    *value = (data >> (8*n)) & bytemask[size];
    pr_debug("read_config_byte read %#x\n", *value);
    return PCIBIOS_SUCCESSFUL;
}

static int ixp4xx_pci_write_config(struct pci_bus *bus,  unsigned int devfn, int where, int size, u32 value)
{
    u32 n, byte_enables, addr, data;
    u8 bus_num = bus->number;

    pr_debug("write_config_byte %#x to %d size %d dev %d:%d:%d\n", value, where,
        size, bus_num, PCI_SLOT(devfn), PCI_FUNC(devfn));

    n = where % 4;
    byte_enables = byte_lane_enable_bits(n, size);
    if (byte_enables == 0xffffffff)
        return PCIBIOS_BAD_REGISTER_NUMBER;

    addr = ixp4xx_config_addr(bus_num, devfn, where);
    data = value << (8*n);
    if (ixp4xx_pci_write(addr, byte_enables | NP_CMD_CONFIGWRITE, data))
        return PCIBIOS_DEVICE_NOT_FOUND;

    return PCIBIOS_SUCCESSFUL;
}

struct pci_ops ixp4xx_ops = {
    .read =  ixp4xx_pci_read_config,
    .write = ixp4xx_pci_write_config,
};

/*
 * PCI abort handler
 */
static int abort_handler(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
{
    u32 isr, status;

    isr = *PCI_ISR;
    local_read_config(PCI_STATUS, 2, &status);
    pr_debug("PCI: abort_handler addr = %#lx, isr = %#x, "
        "status = %#x\n", addr, isr, status);

    /* make sure the Master Abort bit is reset */    
    *PCI_ISR = PCI_ISR_PFE;
    status |= PCI_STATUS_REC_MASTER_ABORT;
    local_write_config(PCI_STATUS, 2, status);

    /*
     * If it was an imprecise abort, then we need to correct the
     * return address to be _after_ the instruction.
     */
    if (fsr & (1 << 10))
        regs->ARM_pc += 4;

    return 0;
}


static int ixp4xx_needs_bounce(struct device *dev, dma_addr_t dma_addr, size_t size)
{
    return (dma_addr + size) >= SZ_64M;
}

/*
 * Setup DMA mask to 64MB on PCI devices. Ignore all other devices.
 */
static int ixp4xx_pci_platform_notify(struct device *dev)
{
    if(dev->bus == &pci_bus_type) {
        *dev->dma_mask =  SZ_64M - 1;
        dev->coherent_dma_mask = SZ_64M - 1;
        dmabounce_register_dev(dev, 2048, 4096, ixp4xx_needs_bounce);
    }
    return 0;
}

static int ixp4xx_pci_platform_notify_remove(struct device *dev)
{
    if(dev->bus == &pci_bus_type) {
        dmabounce_unregister_dev(dev);
    }
    return 0;
}

void __init ixp4xx_pci_preinit(void)
{
    unsigned long cpuid = read_cpuid_id();

#ifdef CONFIG_IXP4XX_INDIRECT_PCI
    pcibios_min_mem = 0x10000000; /* 1 GB of indirect PCI MMIO space */
#else
    pcibios_min_mem = 0x48000000; /* 64 MB of PCI MMIO space */
#endif
    /*
     * Determine which PCI read method to use.
     * Rev 0 IXP425 requires workaround.
     */
    if (!(cpuid & 0xf) && cpu_is_ixp42x()) {
        printk("PCI: IXP42x A0 silicon detected - "
            "PCI Non-Prefetch Workaround Enabled\n");
        ixp4xx_pci_read = ixp4xx_pci_read_errata;
    } else
        ixp4xx_pci_read = ixp4xx_pci_read_no_errata;


    /* hook in our fault handler for PCI errors */
    hook_fault_code(16+6, abort_handler, SIGBUS, 0,
            "imprecise external abort");

    pr_debug("setup PCI-AHB(inbound) and AHB-PCI(outbound) address mappings\n");

    /*
     * We use identity AHB->PCI address translation
     * in the 0x48000000 to 0x4bffffff address space
     */
    *PCI_PCIMEMBASE = 0x48494A4B;

    /*
     * We also use identity PCI->AHB address translation
     * in 4 16MB BARs that begin at the physical memory start
     */
    *PCI_AHBMEMBASE = (PHYS_OFFSET & 0xFF000000) +
        ((PHYS_OFFSET & 0xFF000000) >> 8) +
        ((PHYS_OFFSET & 0xFF000000) >> 16) +
        ((PHYS_OFFSET & 0xFF000000) >> 24) +
        0x00010203;

    if (*PCI_CSR & PCI_CSR_HOST) {
        printk("PCI: IXP4xx is host\n");

        pr_debug("setup BARs in controller\n");

        /*
         * We configure the PCI inbound memory windows to be
         * 1:1 mapped to SDRAM
         */
        local_write_config(PCI_BASE_ADDRESS_0, 4, PHYS_OFFSET);
        local_write_config(PCI_BASE_ADDRESS_1, 4, PHYS_OFFSET + SZ_16M);
        local_write_config(PCI_BASE_ADDRESS_2, 4, PHYS_OFFSET + SZ_32M);
        local_write_config(PCI_BASE_ADDRESS_3, 4,
                    PHYS_OFFSET + SZ_32M + SZ_16M);

        /*
         * Enable CSR window at 64 MiB to allow PCI masters
         * to continue prefetching past 64 MiB boundary.
         */
        local_write_config(PCI_BASE_ADDRESS_4, 4, PHYS_OFFSET + SZ_64M);

        /*
         * Enable the IO window to be way up high, at 0xfffffc00
         */
        local_write_config(PCI_BASE_ADDRESS_5, 4, 0xfffffc01);
        local_write_config(0x40, 4, 0x000080FF); /* No TRDY time limit */
    } else {
        printk("PCI: IXP4xx is target - No bus scan performed\n");
    }

    printk("PCI: IXP4xx Using %s access for memory space\n",
#ifndef CONFIG_IXP4XX_INDIRECT_PCI
            "direct"
#else
            "indirect"
#endif
        );

    pr_debug("clear error bits in ISR\n");
    *PCI_ISR = PCI_ISR_PSE | PCI_ISR_PFE | PCI_ISR_PPE | PCI_ISR_AHBE;

    /*
     * Set Initialize Complete in PCI Control Register: allow IXP4XX to
     * respond to PCI configuration cycles. Specify that the AHB bus is
     * operating in big endian mode. Set up byte lane swapping between 
     * little-endian PCI and the big-endian AHB bus 
     */
#ifdef __ARMEB__
    *PCI_CSR = PCI_CSR_IC | PCI_CSR_ABE | PCI_CSR_PDS | PCI_CSR_ADS;
#else
    *PCI_CSR = PCI_CSR_IC | PCI_CSR_ABE;
#endif

    pr_debug("DONE\n");
}

int ixp4xx_setup(int nr, struct pci_sys_data *sys)
{
    struct resource *res;

    if (nr >= 1)
        return 0;

    res = kzalloc(sizeof(*res) * 2, GFP_KERNEL);
    if (res == NULL) {
        /* 
         * If we're out of memory this early, something is wrong,
         * so we might as well catch it here.
         */
        panic("PCI: unable to allocate resources?\n");
    }

    local_write_config(PCI_COMMAND, 2, PCI_COMMAND_MASTER | PCI_COMMAND_MEMORY);

    res[0].name = "PCI I/O Space";
    res[0].start = 0x00000000;
    res[0].end = 0x0000ffff;
    res[0].flags = IORESOURCE_IO;

    res[1].name = "PCI Memory Space";
    res[1].start = PCIBIOS_MIN_MEM;
    res[1].end = PCIBIOS_MAX_MEM;
    res[1].flags = IORESOURCE_MEM;

    request_resource(&ioport_resource, &res[0]);
    request_resource(&iomem_resource, &res[1]);

    pci_add_resource_offset(&sys->resources, &res[0], sys->io_offset);
    pci_add_resource_offset(&sys->resources, &res[1], sys->mem_offset);

    platform_notify = ixp4xx_pci_platform_notify;
    platform_notify_remove = ixp4xx_pci_platform_notify_remove;

    return 1;
}

int dma_set_coherent_mask(struct device *dev, u64 mask)
{
    if (mask >= SZ_64M - 1)
        return 0;

    return -EIO;
}

EXPORT_SYMBOL(ixp4xx_pci_read);
EXPORT_SYMBOL(ixp4xx_pci_write);
EXPORT_SYMBOL(dma_set_coherent_mask);