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
38static 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
72static 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	}
98fallback:
99	return rtas_get_sensor(DR_ENTITY_SENSE, slot->index, state);
100}
101
102int 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 */
141int 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