pci-snapgear.c

linux-2.4.29操作系统的源码

/*
 * linux/arch/sh/kernel/pci-snapgear.c
 *
 * Author:  David McCullough <[e-mail]>
 *
 * Highly leveraged from pci-bigsur.c, written by Dustin McIntire.
 *
 * May be copied or modified under the terms of the GNU General Public
 * License.  See linux/COPYING for more information.
 *
 * PCI initialization for the SnapGear boards
 */

#include <linux/config.h>
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/delay.h>
#include <linux/pci.h>

#include <asm/io.h>
#include <asm/pci-sh7751.h>

#define PCI_REG(reg)        (SH7751_PCIREG_BASE+reg)

/* PCI: default LOCAL memory window sizes (seen from PCI bus) */
#define SNAPGEAR_LSR0_SIZE    (64*(1<<20)) //64MB
#define SNAPGEAR_LSR1_SIZE    (64*(1<<20)) //64MB

/*
 * Initialize the SnapGear PCI interface 
 * Setup hardware to be Central Funtion
 * Copy the BSR regs to the PCI interface
 * Setup PCI windows into local RAM
 */
int __init pcibios_init_platform(void) {
	u32 reg;
	u32 word;
	u32 id;

	PCIDBG(1,"PCI: snapgear_pci_init called\n");
	/* Set the BCR's to enable PCI access */
	reg = inl(SH7751_BCR1);
	reg |= 0x80000;
	outl(reg, SH7751_BCR1);
	
	/* check for SH7751/SH7751R hardware */
	id = inl(SH7751_PCIREG_BASE+SH7751_PCICONF0);
	switch (id) {
	case (SH7751_DEVICE_ID << 16) | SH7751_VENDOR_ID:
		printk("PCI: SH7751 PCI host bridge found.\n");
		break;
	case (SH7751R_DEVICE_ID << 16) | SH7751_VENDOR_ID:
		printk("PCI: SH7751R PCI host bridge found.\n");
		break;
	default:
		printk("PCI: Unknown PCI host bridge (id=0x%x).\n", id);
		return(0);
	}
	
	/* Turn the clocks back on (not done in reset)*/
	outl(0, PCI_REG(SH7751_PCICLKR));
	/* Clear Powerdown IRQ's (not done in reset) */
	word = SH7751_PCIPINT_D3 | SH7751_PCIPINT_D0;
	outl(word, PCI_REG(SH7751_PCICLKR));

#if 0
/*
 *	This code is removed as it is done in the bootloader and doing it
 *	here means the MAC addresses loaded by the bootloader get lost
 */
	/* toggle PCI reset pin */
	word = SH7751_PCICR_PREFIX | SH7751_PCICR_PRST;
	outl(word,PCI_REG(SH7751_PCICR));    
	/* Wait for a long time... not 1 sec. but long enough */
	mdelay(100);
	word = SH7751_PCICR_PREFIX;
	outl(word,PCI_REG(SH7751_PCICR)); 
#endif
	
    /* set the command/status bits to:
     * Wait Cycle Control + Parity Enable + Bus Master +
     * Mem space enable
     */
    word = SH7751_PCICONF1_WCC | SH7751_PCICONF1_PER | 
           SH7751_PCICONF1_BUM | SH7751_PCICONF1_MES;
	outl(word, PCI_REG(SH7751_PCICONF1));

	/* define this host as the host bridge */
	word = SH7751_PCI_HOST_BRIDGE << 24;
	outl(word, PCI_REG(SH7751_PCICONF2));

	/* Set IO and Mem windows to local address 
	 * Make PCI and local address the same for easy 1 to 1 mapping 
	 * Window0 = SNAPGEAR_LSR0_SIZE @ non-cached CS2 base = SDRAM
	 * Window1 = SNAPGEAR_LSR1_SIZE @ cached CS2 base = SDRAM 
	 */
	word = SNAPGEAR_LSR0_SIZE - 1;
	outl(word, PCI_REG(SH7751_PCILSR0));
	word = SNAPGEAR_LSR1_SIZE - 1;
	outl(word, PCI_REG(SH7751_PCILSR1));
	/* Set the values on window 0 PCI config registers */
	word = P2SEGADDR(SH7751_CS2_BASE_ADDR);
	outl(word, PCI_REG(SH7751_PCILAR0));
	outl(word, PCI_REG(SH7751_PCICONF5));
	/* Set the values on window 1 PCI config registers */
	word =  PHYSADDR(SH7751_CS2_BASE_ADDR);
	outl(word, PCI_REG(SH7751_PCILAR1));
	outl(word, PCI_REG(SH7751_PCICONF6));

	/* Set the local 16MB PCI memory space window to 
	 * the lowest PCI mapped address
	 */
	word = PCIBIOS_MIN_MEM & SH7751_PCIMBR_MASK;
	PCIDBG(2,"PCI: Setting upper bits of Memory window to 0x%x\n", word);
	outl(word , PCI_REG(SH7751_PCIMBR));

	/* Map IO space into PCI IO window
	 * The IO window is 64K-PCIBIOS_MIN_IO in size
	 * IO addresses will be translated to the 
	 * PCI IO window base address
	 */
	PCIDBG(3,"PCI: Mapping IO address 0x%x - 0x%x to base 0x%x\n", PCIBIOS_MIN_IO,
	    (64*1024), SH7751_PCI_IO_BASE+PCIBIOS_MIN_IO);
	    
	/* Make sure the MSB's of IO window are set to access PCI space correctly */
	word = PCIBIOS_MIN_IO & SH7751_PCIIOBR_MASK;
	PCIDBG(2,"PCI: Setting upper bits of IO window to 0x%x\n", word);
	outl(word, PCI_REG(SH7751_PCIIOBR));
	
	/* Set PCI WCRx, BCRx's, copy from BSC locations */
	word = inl(SH7751_BCR1);
	/* check BCR for SDRAM in area 3 */
	if(((word >> 2) & 1) == 0) {
		printk("PCI: Area 2 is not configured for SDRAM. BCR1=0x%x\n", word);
		return 0;
	}
	outl(word, PCI_REG(SH7751_PCIBCR1));
	word = (u16)inw(SH7751_BCR2);
	/* check BCR2 for 32bit SDRAM interface*/
	if(((word >> 4) & 0x3) != 0x3) {
		printk("PCI: Area 2 is not 32 bit SDRAM. BCR2=0x%x\n", word);
		return 0;
	}
	outl(word, PCI_REG(SH7751_PCIBCR2));
	/* configure the wait control registers */
	word = inl(SH7751_WCR1);
	outl(word, PCI_REG(SH7751_PCIWCR1));
	word = inl(SH7751_WCR2);
	outl(word, PCI_REG(SH7751_PCIWCR2));
	word = inl(SH7751_WCR3);
	outl(word, PCI_REG(SH7751_PCIWCR3));
	word = inl(SH7751_MCR);
	outl(word, PCI_REG(SH7751_PCIMCR));

	/* NOTE: I'm ignoring the PCI error IRQs for now..
	 * TODO: add support for the internal error interrupts and
	 * DMA interrupts...
	 */
	 
	/* SH7751 init done, set central function init complete */
	/* use round robin mode to stop a device starving/overruning */
	word = SH7751_PCICR_PREFIX | SH7751_PCICR_CFIN | SH7751_PCICR_ARBM;
	outl(word,PCI_REG(SH7751_PCICR)); 
	PCIDBG(2,"PCI: snapgear_pci_init finished\n");

	return 1;
}

int __init pcibios_map_platform_irq(u8 slot, u8 pin)
{
	int irq = -1;

	switch (slot) {
	case 8:  /* the PCI bridge */ break;
	case 11: irq = 8;  break; /* USB    */
	case 12: irq = 11; break; /* PCMCIA */
	case 13: irq = 5;  break; /* eth0   */
	case 14: irq = 8;  break; /* eth1   */
	case 15: irq = 11; break; /* safenet (unused) */
	}

    printk("PCI: Mapping SnapGear IRQ for slot %d, pin %c to irq %d\n",
			slot, pin - 1 + 'A', irq);

    return irq;
}