drivers/pci/hotplug/rpaphp_pci.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * PCI Hot Plug Controller Driver for RPA-compliant PPC64 platform.
   4  * Copyright (C) 2003 Linda Xie <lxie@us.ibm.com>
   5  *
   6  * All rights reserved.
   7  *
   8  * Send feedback to <lxie@us.ibm.com>
   9  *
  10  */
  11 #include <linux/of.h>
  12 #include <linux/pci.h>
  13 #include <linux/string.h>
  14
  15 #include <asm/pci-bridge.h>
  16 #include <asm/rtas.h>
  17 #include <asm/machdep.h>
  18
  19 #include "../pci.h"             /* for pci_add_new_bus */
  20 #include "rpaphp.h"
  21
  22 /*
  23  * RTAS call get-sensor-state(DR_ENTITY_SENSE) return values as per PAPR:
  24  * -- generic return codes ---
  25  *    -1: Hardware Error
  26  *    -2: RTAS_BUSY
  27  *    -3: Invalid sensor. RTAS Parameter Error.
  28  * -- rtas_get_sensor function specific return codes ---
  29  * -9000: Need DR entity to be powered up and unisolated before RTAS call
  30  * -9001: Need DR entity to be powered up, but not unisolated, before RTAS call
  31  * -9002: DR entity unusable
  32  *  990x: Extended delay - where x is a number in the range of 0-5
  33  */
  34 #define RTAS_SLOT_UNISOLATED            -9000
  35 #define RTAS_SLOT_NOT_UNISOLATED        -9001
  36 #define RTAS_SLOT_NOT_USABLE            -9002
  37
  38 static int rtas_get_sensor_errno(int rtas_rc)
  39 {
  40         switch (rtas_rc) {
  41         case 0:
  42                 /* Success case */
  43                 return 0;
  44         case RTAS_SLOT_UNISOLATED:
  45         case RTAS_SLOT_NOT_UNISOLATED:
  46                 return -EFAULT;
  47         case RTAS_SLOT_NOT_USABLE:
  48                 return -ENODEV;
  49         case RTAS_BUSY:
  50         case RTAS_EXTENDED_DELAY_MIN...RTAS_EXTENDED_DELAY_MAX:
  51                 return -EBUSY;
  52         default:
  53                 return rtas_error_rc(rtas_rc);
  54         }
  55 }
  56
  57 /*
  58  * get_adapter_status() can be called by the EEH handler during EEH recovery.
  59  * On certain PHB failures, the RTAS call rtas_call(get-sensor-state) returns
  60  * extended busy error (9902) until PHB is recovered by pHyp. The RTAS call
  61  * interface rtas_get_sensor() loops over the RTAS call on extended delay
  62  * return code (9902) until the return value is either success (0) or error
  63  * (-1). This causes the EEH handler to get stuck for ~6 seconds before it
  64  * could notify that the PCI error has been detected and stop any active
  65  * operations. This sometimes causes EEH recovery to fail. To avoid this issue,
  66  * invoke rtas_call(get-sensor-state) directly if the respective PE is in EEH
  67  * recovery state and return -EBUSY error based on RTAS return status. This
  68  * will help the EEH handler to notify the driver about the PCI error
  69  * immediately and successfully proceed with EEH recovery steps.
  70  */
  71
  72 static int __rpaphp_get_sensor_state(struct slot *slot, int *state)
  73 {
  74         int rc;
  75         int token = rtas_token("get-sensor-state");
  76         struct pci_dn *pdn;
  77         struct eeh_pe *pe;
  78         struct pci_controller *phb = PCI_DN(slot->dn)->phb;
  79
  80         if (token == RTAS_UNKNOWN_SERVICE)
  81                 return -ENOENT;
  82
  83         /*
  84          * Fallback to existing method for empty slot or PE isn't in EEH
  85          * recovery.
  86          */
  87         pdn = list_first_entry_or_null(&PCI_DN(phb->dn)->child_list,
  88                                         struct pci_dn, list);
  89         if (!pdn)
  90                 goto fallback;
  91
  92         pe = eeh_dev_to_pe(pdn->edev);
  93         if (pe && (pe->state & EEH_PE_RECOVERING)) {
  94                 rc = rtas_call(token, 2, 2, state, DR_ENTITY_SENSE,
  95                                slot->index);
  96                 return rtas_get_sensor_errno(rc);
  97         }
  98 fallback:
  99         return rtas_get_sensor(DR_ENTITY_SENSE, slot->index, state);
 100 }
 101
 102 int rpaphp_get_sensor_state(struct slot *slot, int *state)
 103 {
 104         int rc;
 105         int setlevel;
 106
 107         rc = __rpaphp_get_sensor_state(slot, state);
 108
 109         if (rc < 0) {
 110                 if (rc == -EFAULT || rc == -EEXIST) {
 111                         dbg("%s: slot must be power up to get sensor-state\n",
 112                             __func__);
 113
 114                         /* some slots have to be powered up
 115                          * before get-sensor will succeed.
 116                          */
 117                         rc = rtas_set_power_level(slot->power_domain, POWER_ON,
 118                                                   &setlevel);
 119                         if (rc < 0) {
 120                                 dbg("%s: power on slot[%s] failed rc=%d.\n",
 121                                     __func__, slot->name, rc);
 122                         } else {
 123                                 rc = __rpaphp_get_sensor_state(slot, state);
 124                         }
 125                 } else if (rc == -ENODEV)
 126                         info("%s: slot is unusable\n", __func__);
 127                 else
 128                         err("%s failed to get sensor state\n", __func__);
 129         }
 130         return rc;
 131 }
 132
 133 /**
 134  * rpaphp_enable_slot - record slot state, config pci device
 135  * @slot: target &slot
 136  *
 137  * Initialize values in the slot structure to indicate if there is a pci card
 138  * plugged into the slot. If the slot is not empty, run the pcibios routine
 139  * to get pcibios stuff correctly set up.
 140  */
 141 int rpaphp_enable_slot(struct slot *slot)
 142 {
 143         int rc, level, state;
 144         struct pci_bus *bus;
 145
 146         slot->state = EMPTY;
 147
 148         /* Find out if the power is turned on for the slot */
 149         rc = rtas_get_power_level(slot->power_domain, &level);
 150         if (rc)
 151                 return rc;
 152
 153         /* Figure out if there is an adapter in the slot */
 154         rc = rpaphp_get_sensor_state(slot, &state);
 155         if (rc)
 156                 return rc;
 157
 158         bus = pci_find_bus_by_node(slot->dn);
 159         if (!bus) {
 160                 err("%s: no pci_bus for dn %pOF\n", __func__, slot->dn);
 161                 return -EINVAL;
 162         }
 163
 164         slot->bus = bus;
 165         slot->pci_devs = &bus->devices;
 166
 167         /* if there's an adapter in the slot, go add the pci devices */
 168         if (state == PRESENT) {
 169                 slot->state = NOT_CONFIGURED;
 170
 171                 /* non-empty slot has to have child */
 172                 if (!slot->dn->child) {
 173                         err("%s: slot[%s]'s device_node doesn't have child for adapter\n",
 174                             __func__, slot->name);
 175                         return -EINVAL;
 176                 }
 177
 178                 if (list_empty(&bus->devices)) {
 179                         pseries_eeh_init_edev_recursive(PCI_DN(slot->dn));
 180                         pci_hp_add_devices(bus);
 181                 }
 182
 183                 if (!list_empty(&bus->devices)) {
 184                         slot->state = CONFIGURED;
 185                 }
 186
 187                 if (rpaphp_debug) {
 188                         struct pci_dev *dev;
 189                         dbg("%s: pci_devs of slot[%pOF]\n", __func__, slot->dn);
 190                         list_for_each_entry(dev, &bus->devices, bus_list)
 191                                 dbg("\t%s\n", pci_name(dev));
 192                 }
 193         }
 194
 195         return 0;
 196 }