src/northbridge/via/vx900/pcie.c

   1 /*
   2  * This file is part of the coreboot project.
   3  *
   4  * Copyright (C) 2013  Alexandru Gagniuc <mr.nuke.me@gmail.com>
   5  *
   6  * This program is free software: you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation, either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include <arch/io.h>
  18 #include <console/console.h>
  19 #include <device/pci.h>
  20 #include <device/pciexp.h>
  21 #include <device/pci_ids.h>
  22
  23 #include "vx900.h"
  24
  25 /**
  26  * @file vx900/pcie.c
  27  *
  28  * STATUS:
  29  * We do part of the sequence to initialize the PCIE link. The problem is that
  30  * the reset signal for each slot is connected to a GPO pin, but We don't know
  31  * which GPO pin. We need to figure out which GPIO pin is hooked to which slot,
  32  * and have a mechanism to specify this per-mainboard (devicetree.cb).
  33  *
  34  * There is currently no timeout detection mechanism for when a link comes up.
  35  * If the link never comes up, we hang.
  36  */
  37
  38 static void vx900_pcie_link_init(struct device *dev)
  39 {
  40         u8 reg8;
  41         u32 reg32;
  42
  43         u8 fn = dev->path.pci.devfn & 0x07;
  44
  45         /* Step 1 : Check for presence of PCIE device */
  46         reg8 = pci_read_config8(dev, 0x5a);
  47
  48         if (reg8 & (1 << 6))
  49                 printk(BIOS_DEBUG, "Card detected in PEX%i\n", fn);
  50         else
  51                 return;
  52
  53         /* Step 2: Wait for device to enter L0 state */
  54         /* FIXME: implement timeout detection */
  55         while (0x8a != pci_read_config8(dev, 0x1c3));
  56
  57         /* Step 3: Clear PCIe error status, then check for failures */
  58         pci_write_config32(dev, 0x104, 0xffffffff);
  59         reg32 = pci_read_config32(dev, 0x104);
  60         if (0 != reg32) {
  61                 printk(BIOS_DEBUG, "PEX init error. flags 0x%.8x\n", reg32);
  62                 return;
  63         }
  64
  65         pci_write_config32(dev, 0x110, 0xffffffff);
  66         reg32 = pci_read_config32(dev, 0x110);
  67         if (0 != reg32)
  68                 printk(BIOS_DEBUG, "PEX errors. flags 0x%.8x\n", reg32);
  69
  70         pci_write_config8(dev, 0xa4, 0xff);
  71         if (pci_read_config8(dev, 0x4a) & (1 << 3))
  72                 printk(BIOS_DEBUG, "Unsupported request detected.\n");
  73
  74         pci_write_config8(dev, 0x15a, 0xff);
  75         if (pci_read_config8(dev, 0x15a) & (1 << 1))
  76                 printk(BIOS_DEBUG, "Negotiation pending.\n");
  77
  78         /* Step 4: Read vendor ID */
  79         /* FIXME: Do we want to run through the whole sequence and delay boot
  80          * by several seconds if the device does not respond properly the first
  81          * time? */
  82 }
  83
  84 static void vx900_pex_dev_set_resources(struct device *dev)
  85 {
  86         assign_resources(dev->link_list);
  87 }
  88
  89 static void vx900_pex_init(struct device *dev)
  90 {
  91         /* FIXME: For some reason, PEX0 hangs on init. Find issue, fix it. */
  92         if ((dev->path.pci.devfn & 0x7) == 0)
  93                 return;
  94
  95         vx900_pcie_link_init(dev);
  96 }
  97
  98 static struct device_operations vx900_pex_ops = {
  99         .read_resources = pci_bus_read_resources,
 100         .set_resources = vx900_pex_dev_set_resources,
 101         .enable_resources = pci_bus_enable_resources,
 102         .init = vx900_pex_init,
 103         .scan_bus = pciexp_scan_bridge,
 104         .reset_bus = pci_bus_reset,
 105 };
 106
 107 static const unsigned short pci_device_ids[] = {
 108         PCI_DEVICE_ID_VIA_VX900_PEX1,
 109         PCI_DEVICE_ID_VIA_VX900_PEX2,
 110         PCI_DEVICE_ID_VIA_VX900_PEX3,
 111         PCI_DEVICE_ID_VIA_VX900_PEX4,
 112         0,
 113 };
 114
 115 static const struct pci_driver pex_driver __pci_driver = {
 116         .ops = &vx900_pex_ops,
 117         .vendor = PCI_VENDOR_ID_VIA,
 118         .devices = pci_device_ids,
 119
 120 };