xref: /openbmc/linux/drivers/pci/hotplug/rpaphp_pci.c (revision 77583f77)
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 
rtas_get_sensor_errno(int rtas_rc)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 
__rpaphp_get_sensor_state(struct slot * slot,int * state)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 
rpaphp_get_sensor_state(struct slot * slot,int * state)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  */
rpaphp_enable_slot(struct slot * slot)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 }
197