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kernel/linux-imx6_3.14.28/arch/x86/pci/numachip.c 2.91 KB
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  /*
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   *
   * Numascale NumaConnect-specific PCI code
   *
   * Copyright (C) 2012 Numascale AS. All rights reserved.
   *
   * Send feedback to <support@numascale.com>
   *
   * PCI accessor functions derived from mmconfig_64.c
   *
   */
  
  #include <linux/pci.h>
  #include <asm/pci_x86.h>
  
  static u8 limit __read_mostly;
  
  static inline char __iomem *pci_dev_base(unsigned int seg, unsigned int bus, unsigned int devfn)
  {
  	struct pci_mmcfg_region *cfg = pci_mmconfig_lookup(seg, bus);
  
  	if (cfg && cfg->virt)
  		return cfg->virt + (PCI_MMCFG_BUS_OFFSET(bus) | (devfn << 12));
  	return NULL;
  }
  
  static int pci_mmcfg_read_numachip(unsigned int seg, unsigned int bus,
  			  unsigned int devfn, int reg, int len, u32 *value)
  {
  	char __iomem *addr;
  
  	/* Why do we have this when nobody checks it. How about a BUG()!? -AK */
  	if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095))) {
  err:		*value = -1;
  		return -EINVAL;
  	}
  
  	/* Ensure AMD Northbridges don't decode reads to other devices */
  	if (unlikely(bus == 0 && devfn >= limit)) {
  		*value = -1;
  		return 0;
  	}
  
  	rcu_read_lock();
  	addr = pci_dev_base(seg, bus, devfn);
  	if (!addr) {
  		rcu_read_unlock();
  		goto err;
  	}
  
  	switch (len) {
  	case 1:
  		*value = mmio_config_readb(addr + reg);
  		break;
  	case 2:
  		*value = mmio_config_readw(addr + reg);
  		break;
  	case 4:
  		*value = mmio_config_readl(addr + reg);
  		break;
  	}
  	rcu_read_unlock();
  
  	return 0;
  }
  
  static int pci_mmcfg_write_numachip(unsigned int seg, unsigned int bus,
  			   unsigned int devfn, int reg, int len, u32 value)
  {
  	char __iomem *addr;
  
  	/* Why do we have this when nobody checks it. How about a BUG()!? -AK */
  	if (unlikely((bus > 255) || (devfn > 255) || (reg > 4095)))
  		return -EINVAL;
  
  	/* Ensure AMD Northbridges don't decode writes to other devices */
  	if (unlikely(bus == 0 && devfn >= limit))
  		return 0;
  
  	rcu_read_lock();
  	addr = pci_dev_base(seg, bus, devfn);
  	if (!addr) {
  		rcu_read_unlock();
  		return -EINVAL;
  	}
  
  	switch (len) {
  	case 1:
  		mmio_config_writeb(addr + reg, value);
  		break;
  	case 2:
  		mmio_config_writew(addr + reg, value);
  		break;
  	case 4:
  		mmio_config_writel(addr + reg, value);
  		break;
  	}
  	rcu_read_unlock();
  
  	return 0;
  }
  
  const struct pci_raw_ops pci_mmcfg_numachip = {
  	.read = pci_mmcfg_read_numachip,
  	.write = pci_mmcfg_write_numachip,
  };
  
  int __init pci_numachip_init(void)
  {
  	int ret = 0;
  	u32 val;
  
  	/* For remote I/O, restrict bus 0 access to the actual number of AMD
  	   Northbridges, which starts at device number 0x18 */
  	ret = raw_pci_read(0, 0, PCI_DEVFN(0x18, 0), 0x60, sizeof(val), &val);
  	if (ret)
  		goto out;
  
  	/* HyperTransport fabric size in bits 6:4 */
  	limit = PCI_DEVFN(0x18 + ((val >> 4) & 7) + 1, 0);
  
  	/* Use NumaChip PCI accessors for non-extended and extended access */
  	raw_pci_ops = raw_pci_ext_ops = &pci_mmcfg_numachip;
  out:
  	return ret;
  }