[RFC/PATCH 6/7] RTAS MSI implementation
Michael Ellerman
michael at ellerman.id.au
Fri Sep 29 07:53:42 EST 2006
Powerpc MSI support via RTAS. Based on Jake's code.
Signed-off-by: Michael Ellerman <michael at ellerman.id.au>
---
arch/powerpc/kernel/Makefile | 1
arch/powerpc/kernel/msi-rtas.c | 246 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 247 insertions(+)
Index: to-merge/arch/powerpc/kernel/Makefile
===================================================================
--- to-merge.orig/arch/powerpc/kernel/Makefile
+++ to-merge/arch/powerpc/kernel/Makefile
@@ -69,6 +69,7 @@ pci32-$(CONFIG_PPC32) := pci_32.o
obj-$(CONFIG_PCI) += $(pci64-y) $(pci32-y)
msiobj-y := msi.o
+msiobj-$(CONFIG_PPC_PSERIES) += msi-rtas.o
obj-$(CONFIG_PCI_MSI) += $(msiobj-y)
kexec-$(CONFIG_PPC64) := machine_kexec_64.o
Index: to-merge/arch/powerpc/kernel/msi-rtas.c
===================================================================
--- /dev/null
+++ to-merge/arch/powerpc/kernel/msi-rtas.c
@@ -0,0 +1,246 @@
+/*
+ * Copyright (C) 2006 Jake Moilanen <moilanen at austin.ibm.com>, IBM Corp.
+ * Copyright (C) 2006 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.
+ *
+ */
+
+#define DEBUG 1
+
+#include <linux/irq.h>
+#include <asm/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_MSI_FN 0
+#define RTAS_CHANGE_MSI_FN 1
+#define RTAS_RESET_MSI_FN 2
+
+
+/* RTAS Helpers */
+
+static int rtas_change_msi(struct pci_dn *pdn, u32 function, u32 num_irqs)
+{
+ u32 addr, seq_num, rtas_ret[2];
+ unsigned long buid;
+ int rc;
+
+ addr = rtas_config_addr(pdn->busno, pdn->devfn, 0);
+ buid = pdn->phb->buid;
+
+ seq_num = 1;
+ do {
+ rc = rtas_call(change_token, 6, 3, rtas_ret, addr,
+ BUID_HI(buid), BUID_LO(buid),
+ function, num_irqs, seq_num);
+
+ seq_num = rtas_ret[1];
+ } while (rtas_busy_delay(rc));
+
+ if (rc) {
+ printk(KERN_WARNING "Error[%d]: getting the number of"
+ " MSI interrupts for %s\n", rc, pci_name(pdn->pcidev));
+ return rc;
+ }
+
+ return rtas_ret[0];
+}
+
+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) {
+ printk(KERN_WARNING "Error[%d]: Querying irq source number "
+ "for %s\n", rc, pci_name(pdn->pcidev));
+ return rc;
+ }
+
+ return rtas_ret[0];
+}
+
+/*
+ * The spec gives firmware the option to enable either MSI or MSI-X,
+ * this doesn't wash with the Linux API. For the time beinging, we
+ * kludge around that by checking ourselves the right type is enabled.
+ */
+static int check_msi_type(struct pci_dev *pdev, int type)
+{
+ int pos, msi_enabled, msix_enabled;
+ u16 reg;
+
+ pos = pci_find_capability(pdev, PCI_CAP_ID_MSI);
+ if (!pos)
+ return -1;
+
+ pci_read_config_word(pdev, pos + PCI_MSI_FLAGS, ®);
+
+ msi_enabled = msix_enabled = 0;
+
+ if (reg & PCI_MSI_FLAGS_ENABLE)
+ msi_enabled = 1;
+
+ if (reg & PCI_MSIX_FLAGS_ENABLE)
+ msix_enabled = 1;
+
+ if (type == PCI_CAP_ID_MSI && (msix_enabled || !msi_enabled)) {
+ pr_debug("check_msi_type: Expected MSI but got %s.\n",
+ msix_enabled ? "MSI-X" : "none");
+ return -1;
+ }
+
+ if (type == PCI_CAP_ID_MSIX && (msi_enabled || !msix_enabled)) {
+ pr_debug("check_msi_type: Expected MSI-X but got %s.\n",
+ msi_enabled ? "MSI" : "none");
+ return -1;
+ }
+
+ return 0;
+}
+
+static void msi_rtas_free(struct pci_dev *pdev, int num,
+ struct msix_entry *entries, int type)
+{
+ struct device_node *dn;
+ struct pci_dn *pdn;
+ int i;
+
+ dn = pci_device_to_OF_node(pdev);
+ if (!dn) {
+ pr_debug("msi_rtas_free: No OF device node for %s\n",
+ pci_name(pdev));
+ return;
+ }
+
+ pdn = PCI_DN(dn);
+ if (!pdn) {
+ pr_debug("msi_rtas_free: No PCI DN for %s\n",
+ pci_name(pdev));
+ return;
+ }
+
+ for (i = 0; i < num; i++) {
+ irq_dispose_mapping(entries[i].vector);
+ }
+
+ /* XXX can we do anything sane if this fails? */
+ rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, 0);
+}
+
+static int msi_rtas_check(struct pci_dev *pdev, int num,
+ struct msix_entry *entries, int type)
+{
+ struct device_node *dn;
+ int i;
+
+ dn = pci_device_to_OF_node(pdev);
+
+ if (!of_find_property(dn, "ibm,req#msi", NULL)) {
+ pr_debug("msi_rtas_check: No ibm,req#msi for %s\n",
+ pci_name(pdev));
+ return -1;
+ }
+
+ /*
+ * Firmware gives us no control over which entries are allocated
+ * for MSI-X, it seems to assume we want 0 - n. For now just insist
+ * that the entries array entry members are 0 - n.
+ */
+ for (i = 0; i < num; i++) {
+ if (entries[i].entry != i) {
+ pr_debug("msi_rtas_check: entries[i].entry != i\n");
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+static int msi_rtas_alloc(struct pci_dev *pdev, int num,
+ struct msix_entry *entries, int type)
+{
+ struct pci_dn *pdn;
+ int hwirq, virq, i;
+
+ pdn = PCI_DN(pci_device_to_OF_node(pdev));
+
+ /*
+ * In the case of an error it's not clear whether the device is left
+ * with MSI enabled or not, I think we should explicitly disable.
+ */
+ if (rtas_change_msi(pdn, RTAS_CHANGE_MSI_FN, num) != num)
+ goto out_free;
+
+ if (check_msi_type(pdev, type))
+ goto out_free;
+
+ for (i = 0; i < num; i++) {
+ hwirq = rtas_query_irq_number(pdn, i);
+ if (hwirq < 0)
+ goto out_free;
+
+ virq = irq_create_mapping(NULL, hwirq);
+
+ if (virq == NO_IRQ) {
+ pr_debug("msi_rtas_alloc: Failed mapping hwirq %d\n",
+ hwirq);
+ goto out_free;
+ }
+
+ entries[i].vector = virq;
+ }
+
+ return 0;
+
+ out_free:
+ msi_rtas_free(pdev, num, entries, type);
+ return -1;
+}
+
+static struct ppc_msi_ops rtas_msi_ops = {
+ .check = msi_rtas_check,
+ .alloc = msi_rtas_alloc,
+ .free = msi_rtas_free
+};
+
+static struct ppc_msi_ops *rtas_get_msi_ops(struct pci_dev *pdev)
+{
+ return &rtas_msi_ops;
+}
+
+static int msi_rtas_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_init: Couldn't find RTAS tokens, no "
+ "MSI support available.\n");
+ return 0;
+ }
+
+ pr_debug("rtas_msi_init: Registering RTAS MSI ops.\n");
+
+ ppc_md.get_msi_ops = rtas_get_msi_ops;
+
+ return 0;
+}
+__initcall(msi_rtas_init);
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