/*
* Copyright 2006 Jake Moilanen <moilanen@austin.ibm.com>, IBM Corp.
* Copyright 2006-2007 Michael Ellerman, IBM Corp.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; version 2 of the
* License.
*
*/
#include <linux/device.h>
#include <linux/irq.h>
#include <linux/msi.h>
#include <asm/rtas.h>
#include <asm/hw_irq.h>
#include <asm/ppc-pci.h>
static int query_token, change_token;
#define RTAS_QUERY_FN 0
#define RTAS_CHANGE_FN 1
#define RTAS_RESET_FN 2
#define RTAS_CHANGE_MSI_FN 3
#define RTAS_CHANGE_MSIX_FN 4
static struct pci_dn *get_pdn(struct pci_dev *pdev)
{
struct device_node *dn;
struct pci_dn *pdn;
dn = pci_device_to_OF_node(pdev);
if (!dn) {
dev_dbg(&pdev->dev, "rtas_msi: No OF device node\n");
return NULL;
}
pdn = PCI_DN(dn);
if (!pdn) {
dev_dbg(&pdev->dev, "rtas_msi: No PCI DN\n");
return NULL;
}
return pdn;
}
/* RTAS Helpers */
static int rtas_change_msi(struct pci_dn *pdn, u32 func, u32 num_irqs)
{
u32 addr, seq_num, rtas_ret[3];
unsigned long buid;
int rc;
addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
buid = pdn->phb->buid;
seq_num = 1;
do {
if (func == RTAS_CHANGE_MSI_FN || func == RTAS_CHANGE_MSIX_FN)
rc = rtas_call(change_token, 6, 4, rtas_ret, addr,
BUID_HI(buid), BUID_LO(buid),
func, num_irqs, seq_num);
else
rc = rtas_call(change_token, 6, 3, rtas_ret, addr,
BUID_HI(buid), BUID_LO(buid),
func, num_irqs, seq_num);
seq_num = rtas_ret[1];
} while (rtas_busy_delay(rc));
/*
* If the RTAS call succeeded, return the number of irqs allocated.
* If not, make sure we return a negative error code.
*/
if (rc == 0)
rc = rtas_ret[0];
else if (rc > 0)
rc = -rc;
pr_debug("rtas_msi: ibm,change_msi(func=%d,num=%d), got %d rc = %d\n",
func, num_irqs, rtas_ret[0], rc);
return rc;
}
static void rtas_disable_msi(struct pci_dev *pdev)
{
struct pci_dn *pdn;
pdn = get_pdn(pdev);
if (!pdn)
return;
/*
* disabling MSI with the explicit interface also disables MSI-X
*/
if (rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, 0) != 0) {
/*
* may have failed because explicit interface is not
* present
*/
if (rtas_change_msi(pdn, RTAS_CHANGE_FN, 0) != 0) {
pr_debug("rtas_msi: Setting MSIs to 0 failed!\n");
}
}
}
static int rtas_query_irq_number(struct pci_dn *pdn, int offset)
{
u32 addr, rtas_ret[2];
unsigned long buid;
int rc;
addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
buid = pdn->phb->buid;
do {
rc = rtas_call(query_token, 4, 3, rtas_ret, addr,
BUID_HI(buid), BUID_LO(buid), offset);
} while (rtas_busy_delay(rc));
if (rc) {
pr_debug("rtas_msi: error (%d) querying source number\n", rc);
return rc;
}
return rtas_ret[0];
}
static void rtas_teardown_msi_irqs(struct pci_dev *pdev)
{
struct msi_desc *entry;
list_for_each_entry(entry, &pdev->msi_list, list) {
if (entry->irq == NO_IRQ)
continue;
irq_set_msi_desc(entry->irq, NULL);
irq_dispose_mapping(entry->irq);
}
rtas_disable_msi(pdev);
}
static int check_req(struct pci_dev *pdev, int nvec, char *prop_name)
{
struct device_node *dn;
struct pci_dn *pdn;
const u32 *req_msi;
pdn = get_pdn(pdev);
if (!pdn)
return -ENODEV;
dn = pdn->node;
req_msi = of_get_property(dn, prop_name, NULL);
if (!req_msi) {
pr_debug("rtas_msi: No %s on %s\n", prop_name, dn->full_name);
return -ENOENT;
}
if (*req_msi < nvec) {
pr_debug("rtas_msi: %s requests < %d MSIs\n", prop_name, nvec);
if (*req_msi == 0) /* Be paranoid */
return -ENOSPC;
return *req_msi;
}
return 0;
}
static int check_req_msi(struct pci_dev *pdev, int nvec)
{
return check_req(pdev, nvec, "ibm,req#msi");
}
static int check_req_msix(struct pci_dev *pdev, int nvec)
{
return check_req(pdev, nvec, "ibm,req#msi-x");
}
/* Quota calculation */
static struct device_node *find_pe_total_msi(struct pci_dev *dev, int *total)
{
struct device_node *dn;
const u32 *p;
dn = of_node_get(pci_device_to_OF_node(dev));
while (dn) {
p = of_get_property(dn, "ibm,pe-total-#msi", NULL);
if (p) {
pr_debug("rtas_msi: found prop on dn %s\n",
dn->full_name);
*total = *p;
return dn;
}
dn = of_get_next_parent(dn);
}
return NULL;
}
static struct device_node *find_pe_dn(struct pci_dev *dev, int *total)
{
struct device_node *dn;
/* Found our PE and assume 8 at that point. */
dn = pci_device_to_OF_node(dev);
if (!dn)
return NULL;
dn = find_device_pe(dn);
if (!dn)
return NULL;
/* We actually want the parent */
dn = of_get_parent(dn);
if (!dn)
return NULL;
/* Hardcode of 8 for old firmwares */
*total = 8;
pr_debug("rtas_msi: using PE dn %s\n", dn->full_name);
return dn;
}
struct msi_counts {
struct device_node *requestor;
int num_devices;
int request;
int quota;
int spare;
int over_quota;
};
static void *count_non_bridge_devices(struct device_node *dn, void *data)
{
struct msi_counts *counts = data;
const u32 *p;
u32 class;
pr_debug("rtas_msi: counting %s\n", dn->full_name);
p = of_get_property(dn, "class-code", NULL);
class = p ? *p : 0;
if ((class >> 8) != PCI_CLASS_BRIDGE_PCI)
counts->num_devices++;
return NULL;
}
static void *count_spare_msis(struct device_node *dn, void *data)
{
struct msi_counts *counts = data;
const u32 *p;
int req;
if (dn == counts->requestor)
req = counts->request;
else {
/* We don't know if a driver will try to use MSI or MSI-X,
* so we just have to punt and use the larger of the two. */
req = 0;
p = of_get_property(dn, "ibm,req#msi", NULL);
if (p)
req = *p;
p = of_get_property(dn, "ibm,req#msi-x", NULL);
if (p)
req = max(req, (int)*p);
}
if (req < counts->quota)
counts->spare += counts->quota - req;
else if (req > counts->quota)
counts->over_quota++;
return NULL;
}
static int msi_quota_for_device(struct pci_dev *dev, int request)
{
struct device_node *pe_dn;
struct msi_counts counts;
int total;
pr_debug("rtas_msi: calc quota for %s, request %d\n", pci_name(dev),
request);
pe_dn = find_pe_total_msi(dev, &total);
if (!pe_dn)
pe_dn = find_pe_dn(dev, &total);
if (!pe_dn) {
pr_err("rtas_msi: couldn't find PE for %s\n", pci_name(dev));
goto out;
}
pr_debug("rtas_msi: found PE %s\n", pe_dn->full_name);
memset(&counts, 0, sizeof(struct msi_counts));
/* Work out how many devices we have below this PE */
traverse_pci_devices(pe_dn, count_non_bridge_devices, &counts);
if (counts.num_devices == 0) {
pr_err("rtas_msi: found 0 devices under PE for %s\n",
pci_name(dev));
goto out;
}
counts.quota = total / counts.num_devices;
if (request <= counts.quota)
goto out;
/* else, we have some more calculating to do */
counts.requestor = pci_device_to_OF_node(dev);
counts.request = request;
traverse_pci_devices(pe_dn, count_spare_msis, &counts);
/* If the quota isn't an integer multiple of the total, we can
* use the remainder as spare MSIs for anyone that wants them. */
counts.spare += total % counts.num_devices;
/* Divide any spare by the number of over-quota requestors */
if (counts.over_quota)
counts.quota += counts.spare / counts.over_quota;
/* And finally clamp the request to the possibly adjusted quota */
request = min(counts.quota, request);
pr_debug("rtas_msi: request clamped to quota %d\n", request);
out:
of_node_put(pe_dn);
return request;
}
static int rtas_msi_check_device(struct pci_dev *pdev, int nvec, int type)
{
int quota, rc;
if (type == PCI_CAP_ID_MSIX)
rc = check_req_msix(pdev, nvec);
else
rc = check_req_msi(pdev, nvec);
if (rc)
return rc;
quota = msi_quota_for_device(pdev, nvec);
if (quota && quota < nvec)
return quota;
return 0;
}
static int check_msix_entries(struct pci_dev *pdev)
{
struct msi_desc *entry;
int expected;
/* There's no way for us to express to firmware that we want
* a discontiguous, or non-zero based, range of MSI-X entries.
* So we must reject such requests. */
expected = 0;
list_for_each_entry(entry, &pdev->msi_list, list) {
if (entry->msi_attrib.entry_nr != expected) {
pr_debug("rtas_msi: bad MSI-X entries.\n");
return -EINVAL;
}
expected++;
}
return 0;
}
static int rtas_setup_msi_irqs(struct pci_dev *pdev, int nvec, int type)
{
struct pci_dn *pdn;
int hwirq, virq, i, rc;
struct msi_desc *entry;
struct msi_msg msg;
pdn = get_pdn(pdev);
if (!pdn)
return -ENODEV;
if (type == PCI_CAP_ID_MSIX && check_msix_entries(pdev))
return -EINVAL;
/*
* Try the new more explicit firmware interface, if that fails fall
* back to the old interface. The old interface is known to never
* return MSI-Xs.
*/
if (type == PCI_CAP_ID_MSI) {
rc = rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, nvec);
if (rc < 0) {
pr_debug("rtas_msi: trying the old firmware call.\n");
rc = rtas_change_msi(pdn, RTAS_CHANGE_FN, nvec);
}
} else
rc = rtas_change_msi(pdn, RTAS_CHANGE_MSIX_FN, nvec);
if (rc != nvec) {
pr_debug("rtas_msi: rtas_change_msi() failed\n");
return rc;
}
i = 0;
list_for_each_entry(entry, &pdev->msi_list, list) {
hwirq = rtas_query_irq_number(pdn, i++);
if (hwirq < 0) {
pr_debug("rtas_msi: error (%d) getting hwirq\n", rc);
return hwirq;
}
virq = irq_create_mapping(NULL, hwirq);
if (virq == NO_IRQ) {
pr_debug("rtas_msi: Failed mapping hwirq %d\n", hwirq);
return -ENOSPC;
}
dev_dbg(&pdev->dev, "rtas_msi: allocated virq %d\n", virq);
irq_set_msi_desc(virq, entry);
/* Read config space back so we can restore after reset */
read_msi_msg(virq, &msg);
entry->msg = msg;
}
return 0;
}
static void rtas_msi_pci_irq_fixup(struct pci_dev *pdev)
{
/* No LSI -> leave MSIs (if any) configured */
if (pdev->irq == NO_IRQ) {
dev_dbg(&pdev->dev, "rtas_msi: no LSI, nothing to do.\n");
return;
}
/* No MSI -> MSIs can't have been assigned by fw, leave LSI */
if (check_req_msi(pdev, 1) && check_req_msix(pdev, 1)) {
dev_dbg(&pdev->dev, "rtas_msi: no req#msi/x, nothing to do.\n");
return;
}
dev_dbg(&pdev->dev, "rtas_msi: disabling existing MSI.\n");
rtas_disable_msi(pdev);
}
static int rtas_msi_init(void)
{
query_token = rtas_token("ibm,query-interrupt-source-number");
change_token = rtas_token("ibm,change-msi");
if ((query_token == RTAS_UNKNOWN_SERVICE) ||
(change_token == RTAS_UNKNOWN_SERVICE)) {
pr_debug("rtas_msi: no RTAS tokens, no MSI support.\n");
return -1;
}
pr_debug("rtas_msi: Registering RTAS MSI callbacks.\n");
WARN_ON(ppc_md.setup_msi_irqs);
ppc_md.setup_msi_irqs = rtas_setup_msi_irqs;
ppc_md.teardown_msi_irqs = rtas_teardown_msi_irqs;
ppc_md.msi_check_device = rtas_msi_check_device;
WARN_ON(ppc_md.pci_irq_fixup);
ppc_md.pci_irq_fixup = rtas_msi_pci_irq_fixup;
return 0;
}
arch_initcall(rtas_msi_init);
