[IA64] hotplug/ia64: SN Hotplug Driver: SN IRQ Fixes
Prarit Bhargava [Wed, 6 Jul 2005 21:59:44 +0000 (14:59 -0700)]
This patch  fixes the SN IRQ code such that cpu affinity and
Hotplug can modify IRQ values.  The sn_irq_info structures are now locked
using a RCU lock mechanism to avoid lock contention in the lost interrupt
WAR code.

Signed-off-by: Prarit Bhargava <prarit@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/sn/kernel/io_init.c
arch/ia64/sn/kernel/irq.c
include/asm-ia64/sn/intr.h
include/asm-ia64/sn/pcidev.h

index 783eb43..2f03e3f 100644 (file)
@@ -21,7 +21,6 @@
 #include <asm/sn/simulator.h>
 #include <asm/sn/tioca_provider.h>
 
-char master_baseio_wid;
 nasid_t master_nasid = INVALID_NASID;  /* Partition Master */
 
 struct slab_info {
@@ -231,11 +230,13 @@ static void sn_pci_fixup_slot(struct pci_dev *dev)
 {
        int idx;
        int segment = 0;
-       uint64_t size;
-       struct sn_irq_info *sn_irq_info;
-       struct pci_dev *host_pci_dev;
        int status = 0;
        struct pcibus_bussoft *bs;
+       struct pci_bus *host_pci_bus;
+       struct pci_dev *host_pci_dev;
+       struct sn_irq_info *sn_irq_info;
+       unsigned long size;
+       unsigned int bus_no, devfn;
 
        dev->sysdata = kmalloc(sizeof(struct pcidev_info), GFP_KERNEL);
        if (SN_PCIDEV_INFO(dev) <= 0)
@@ -253,7 +254,7 @@ static void sn_pci_fixup_slot(struct pci_dev *dev)
                                     (u64) __pa(SN_PCIDEV_INFO(dev)),
                                     (u64) __pa(sn_irq_info));
        if (status)
-               BUG();          /* Cannot get platform pci device information information */
+               BUG(); /* Cannot get platform pci device information */
 
        /* Copy over PIO Mapped Addresses */
        for (idx = 0; idx <= PCI_ROM_RESOURCE; idx++) {
@@ -275,15 +276,20 @@ static void sn_pci_fixup_slot(struct pci_dev *dev)
                        dev->resource[idx].parent = &iomem_resource;
        }
 
-       /* set up host bus linkages */
-       bs = SN_PCIBUS_BUSSOFT(dev->bus);
-       host_pci_dev =
-           pci_find_slot(SN_PCIDEV_INFO(dev)->pdi_slot_host_handle >> 32,
-                         SN_PCIDEV_INFO(dev)->
-                         pdi_slot_host_handle & 0xffffffff);
+       /* Using the PROMs values for the PCI host bus, get the Linux
+        * PCI host_pci_dev struct and set up host bus linkages
+        */
+
+       bus_no = SN_PCIDEV_INFO(dev)->pdi_slot_host_handle >> 32;
+       devfn = SN_PCIDEV_INFO(dev)->pdi_slot_host_handle & 0xffffffff;
+       host_pci_bus = pci_find_bus(pci_domain_nr(dev->bus), bus_no);
+       host_pci_dev = pci_get_slot(host_pci_bus, devfn);
+
+       SN_PCIDEV_INFO(dev)->host_pci_dev = host_pci_dev;
        SN_PCIDEV_INFO(dev)->pdi_host_pcidev_info =
-           SN_PCIDEV_INFO(host_pci_dev);
+                                               SN_PCIDEV_INFO(host_pci_dev);
        SN_PCIDEV_INFO(dev)->pdi_linux_pcidev = dev;
+       bs = SN_PCIBUS_BUSSOFT(dev->bus);
        SN_PCIDEV_INFO(dev)->pdi_pcibus_info = bs;
 
        if (bs && bs->bs_asic_type < PCIIO_ASIC_MAX_TYPES) {
@@ -297,6 +303,9 @@ static void sn_pci_fixup_slot(struct pci_dev *dev)
                SN_PCIDEV_INFO(dev)->pdi_sn_irq_info = sn_irq_info;
                dev->irq = SN_PCIDEV_INFO(dev)->pdi_sn_irq_info->irq_irq;
                sn_irq_fixup(dev, sn_irq_info);
+       } else {
+               SN_PCIDEV_INFO(dev)->pdi_sn_irq_info = NULL;
+               kfree(sn_irq_info);
        }
 }
 
@@ -403,11 +412,7 @@ static int __init sn_pci_init(void)
         */
        ia64_max_iommu_merge_mask = ~PAGE_MASK;
        sn_fixup_ionodes();
-       sn_irq = kmalloc(sizeof(struct sn_irq_info *) * NR_IRQS, GFP_KERNEL);
-       if (sn_irq <= 0)
-               BUG();          /* Canno afford to run out of memory. */
-       memset(sn_irq, 0, sizeof(struct sn_irq_info *) * NR_IRQS);
-
+       sn_irq_lh_init();
        sn_init_cpei_timer();
 
 #ifdef CONFIG_PROC_FS
index 0f4e813..e6f7551 100644 (file)
@@ -9,6 +9,7 @@
  */
 
 #include <linux/irq.h>
+#include <linux/spinlock.h>
 #include <asm/sn/intr.h>
 #include <asm/sn/addrs.h>
 #include <asm/sn/arch.h>
@@ -25,7 +26,8 @@ static void unregister_intr_pda(struct sn_irq_info *sn_irq_info);
 
 extern int sn_force_interrupt_flag;
 extern int sn_ioif_inited;
-struct sn_irq_info **sn_irq;
+static struct list_head **sn_irq_lh;
+static spinlock_t sn_irq_info_lock = SPIN_LOCK_UNLOCKED; /* non-IRQ lock */
 
 static inline uint64_t sn_intr_alloc(nasid_t local_nasid, int local_widget,
                                     u64 sn_irq_info,
@@ -101,7 +103,7 @@ static void sn_end_irq(unsigned int irq)
                nasid = get_nasid();
                event_occurred = HUB_L((uint64_t *) GLOBAL_MMR_ADDR
                                       (nasid, SH_EVENT_OCCURRED));
-               /* If the UART bit is set here, we may have received an 
+               /* If the UART bit is set here, we may have received an
                 * interrupt from the UART that the driver missed.  To
                 * make sure, we IPI ourselves to force us to look again.
                 */
@@ -115,82 +117,84 @@ static void sn_end_irq(unsigned int irq)
                force_interrupt(irq);
 }
 
+static void sn_irq_info_free(struct rcu_head *head);
+
 static void sn_set_affinity_irq(unsigned int irq, cpumask_t mask)
 {
-       struct sn_irq_info *sn_irq_info = sn_irq[irq];
-       struct sn_irq_info *tmp_sn_irq_info;
+       struct sn_irq_info *sn_irq_info, *sn_irq_info_safe;
        int cpuid, cpuphys;
-       nasid_t t_nasid;        /* nasid to target */
-       int t_slice;            /* slice to target */
-
-       /* allocate a temp sn_irq_info struct to get new target info */
-       tmp_sn_irq_info = kmalloc(sizeof(*tmp_sn_irq_info), GFP_KERNEL);
-       if (!tmp_sn_irq_info)
-               return;
 
        cpuid = first_cpu(mask);
        cpuphys = cpu_physical_id(cpuid);
-       t_nasid = cpuid_to_nasid(cpuid);
-       t_slice = cpuid_to_slice(cpuid);
 
-       while (sn_irq_info) {
-               int status;
-               int local_widget;
-               uint64_t bridge = (uint64_t) sn_irq_info->irq_bridge;
-               nasid_t local_nasid = NASID_GET(bridge);
+       list_for_each_entry_safe(sn_irq_info, sn_irq_info_safe,
+                                sn_irq_lh[irq], list) {
+               uint64_t bridge;
+               int local_widget, status;
+               nasid_t local_nasid;
+               struct sn_irq_info *new_irq_info;
+
+               new_irq_info = kmalloc(sizeof(struct sn_irq_info), GFP_ATOMIC);
+               if (new_irq_info == NULL)
+                       break;
+               memcpy(new_irq_info, sn_irq_info, sizeof(struct sn_irq_info));
+
+               bridge = (uint64_t) new_irq_info->irq_bridge;
+               if (!bridge) {
+                       kfree(new_irq_info);
+                       break; /* irq is not a device interrupt */
+               }
 
-               if (!bridge)
-                       break;  /* irq is not a device interrupt */
+               local_nasid = NASID_GET(bridge);
 
                if (local_nasid & 1)
                        local_widget = TIO_SWIN_WIDGETNUM(bridge);
                else
                        local_widget = SWIN_WIDGETNUM(bridge);
 
-               /* Free the old PROM sn_irq_info structure */
-               sn_intr_free(local_nasid, local_widget, sn_irq_info);
+               /* Free the old PROM new_irq_info structure */
+               sn_intr_free(local_nasid, local_widget, new_irq_info);
+               /* Update kernels new_irq_info with new target info */
+               unregister_intr_pda(new_irq_info);
 
-               /* allocate a new PROM sn_irq_info struct */
+               /* allocate a new PROM new_irq_info struct */
                status = sn_intr_alloc(local_nasid, local_widget,
-                                      __pa(tmp_sn_irq_info), irq, t_nasid,
-                                      t_slice);
-
-               if (status == 0) {
-                       /* Update kernels sn_irq_info with new target info */
-                       unregister_intr_pda(sn_irq_info);
-                       sn_irq_info->irq_cpuid = cpuid;
-                       sn_irq_info->irq_nasid = t_nasid;
-                       sn_irq_info->irq_slice = t_slice;
-                       sn_irq_info->irq_xtalkaddr =
-                           tmp_sn_irq_info->irq_xtalkaddr;
-                       sn_irq_info->irq_cookie = tmp_sn_irq_info->irq_cookie;
-                       register_intr_pda(sn_irq_info);
-
-                       if (IS_PCI_BRIDGE_ASIC(sn_irq_info->irq_bridge_type)) {
-                               pcibr_change_devices_irq(sn_irq_info);
-                       }
+                                      __pa(new_irq_info), irq,
+                                      cpuid_to_nasid(cpuid),
+                                      cpuid_to_slice(cpuid));
+
+               /* SAL call failed */
+               if (status) {
+                       kfree(new_irq_info);
+                       break;
+               }
 
-                       sn_irq_info = sn_irq_info->irq_next;
+               new_irq_info->irq_cpuid = cpuid;
+               register_intr_pda(new_irq_info);
+
+               if (IS_PCI_BRIDGE_ASIC(new_irq_info->irq_bridge_type))
+                       pcibr_change_devices_irq(new_irq_info);
+
+               spin_lock(&sn_irq_info_lock);
+               list_replace_rcu(&sn_irq_info->list, &new_irq_info->list);
+               spin_unlock(&sn_irq_info_lock);
+               call_rcu(&sn_irq_info->rcu, sn_irq_info_free);
 
 #ifdef CONFIG_SMP
-                       set_irq_affinity_info((irq & 0xff), cpuphys, 0);
+               set_irq_affinity_info((irq & 0xff), cpuphys, 0);
 #endif
-               } else {
-                       break;  /* snp_affinity failed the intr_alloc */
-               }
        }
-       kfree(tmp_sn_irq_info);
 }
 
 struct hw_interrupt_type irq_type_sn = {
-       "SN hub",
-       sn_startup_irq,
-       sn_shutdown_irq,
-       sn_enable_irq,
-       sn_disable_irq,
-       sn_ack_irq,
-       sn_end_irq,
-       sn_set_affinity_irq
+       .typename       = "SN hub",
+       .startup        = sn_startup_irq,
+       .shutdown       = sn_shutdown_irq,
+       .enable         = sn_enable_irq,
+       .disable        = sn_disable_irq,
+       .ack            = sn_ack_irq,
+       .end            = sn_end_irq,
+       .set_affinity   = sn_set_affinity_irq
 };
 
 unsigned int sn_local_vector_to_irq(u8 vector)
@@ -231,19 +235,18 @@ static void unregister_intr_pda(struct sn_irq_info *sn_irq_info)
        struct sn_irq_info *tmp_irq_info;
        int i, foundmatch;
 
+       rcu_read_lock();
        if (pdacpu(cpu)->sn_last_irq == irq) {
                foundmatch = 0;
-               for (i = pdacpu(cpu)->sn_last_irq - 1; i; i--) {
-                       tmp_irq_info = sn_irq[i];
-                       while (tmp_irq_info) {
+               for (i = pdacpu(cpu)->sn_last_irq - 1;
+                    i && !foundmatch; i--) {
+                       list_for_each_entry_rcu(tmp_irq_info,
+                                               sn_irq_lh[i],
+                                               list) {
                                if (tmp_irq_info->irq_cpuid == cpu) {
-                                       foundmatch++;
+                                       foundmatch = 1;
                                        break;
                                }
-                               tmp_irq_info = tmp_irq_info->irq_next;
-                       }
-                       if (foundmatch) {
-                               break;
                        }
                }
                pdacpu(cpu)->sn_last_irq = i;
@@ -251,60 +254,27 @@ static void unregister_intr_pda(struct sn_irq_info *sn_irq_info)
 
        if (pdacpu(cpu)->sn_first_irq == irq) {
                foundmatch = 0;
-               for (i = pdacpu(cpu)->sn_first_irq + 1; i < NR_IRQS; i++) {
-                       tmp_irq_info = sn_irq[i];
-                       while (tmp_irq_info) {
+               for (i = pdacpu(cpu)->sn_first_irq + 1;
+                    i < NR_IRQS && !foundmatch; i++) {
+                       list_for_each_entry_rcu(tmp_irq_info,
+                                               sn_irq_lh[i],
+                                               list) {
                                if (tmp_irq_info->irq_cpuid == cpu) {
-                                       foundmatch++;
+                                       foundmatch = 1;
                                        break;
                                }
-                               tmp_irq_info = tmp_irq_info->irq_next;
-                       }
-                       if (foundmatch) {
-                               break;
                        }
                }
                pdacpu(cpu)->sn_first_irq = ((i == NR_IRQS) ? 0 : i);
        }
+       rcu_read_unlock();
 }
 
-struct sn_irq_info *sn_irq_alloc(nasid_t local_nasid, int local_widget, int irq,
-                                nasid_t nasid, int slice)
+static void sn_irq_info_free(struct rcu_head *head)
 {
        struct sn_irq_info *sn_irq_info;
-       int status;
-
-       sn_irq_info = kmalloc(sizeof(*sn_irq_info), GFP_KERNEL);
-       if (sn_irq_info == NULL)
-               return NULL;
-
-       memset(sn_irq_info, 0x0, sizeof(*sn_irq_info));
-
-       status =
-           sn_intr_alloc(local_nasid, local_widget, __pa(sn_irq_info), irq,
-                         nasid, slice);
-
-       if (status) {
-               kfree(sn_irq_info);
-               return NULL;
-       } else {
-               return sn_irq_info;
-       }
-}
-
-void sn_irq_free(struct sn_irq_info *sn_irq_info)
-{
-       uint64_t bridge = (uint64_t) sn_irq_info->irq_bridge;
-       nasid_t local_nasid = NASID_GET(bridge);
-       int local_widget;
-
-       if (local_nasid & 1)    /* tio check */
-               local_widget = TIO_SWIN_WIDGETNUM(bridge);
-       else
-               local_widget = SWIN_WIDGETNUM(bridge);
-
-       sn_intr_free(local_nasid, local_widget, sn_irq_info);
 
+       sn_irq_info = container_of(head, struct sn_irq_info, rcu);
        kfree(sn_irq_info);
 }
 
@@ -314,30 +284,54 @@ void sn_irq_fixup(struct pci_dev *pci_dev, struct sn_irq_info *sn_irq_info)
        int slice = sn_irq_info->irq_slice;
        int cpu = nasid_slice_to_cpuid(nasid, slice);
 
+       pci_dev_get(pci_dev);
+
        sn_irq_info->irq_cpuid = cpu;
        sn_irq_info->irq_pciioinfo = SN_PCIDEV_INFO(pci_dev);
 
        /* link it into the sn_irq[irq] list */
-       sn_irq_info->irq_next = sn_irq[sn_irq_info->irq_irq];
-       sn_irq[sn_irq_info->irq_irq] = sn_irq_info;
+       spin_lock(&sn_irq_info_lock);
+       list_add_rcu(&sn_irq_info->list, sn_irq_lh[sn_irq_info->irq_irq]);
+       spin_unlock(&sn_irq_info_lock);
 
        (void)register_intr_pda(sn_irq_info);
 }
 
+void sn_irq_unfixup(struct pci_dev *pci_dev)
+{
+       struct sn_irq_info *sn_irq_info;
+
+       /* Only cleanup IRQ stuff if this device has a host bus context */
+       if (!SN_PCIDEV_BUSSOFT(pci_dev))
+               return;
+
+       sn_irq_info = SN_PCIDEV_INFO(pci_dev)->pdi_sn_irq_info;
+       if (!sn_irq_info || !sn_irq_info->irq_irq)
+               return;
+
+       unregister_intr_pda(sn_irq_info);
+       spin_lock(&sn_irq_info_lock);
+       list_del_rcu(&sn_irq_info->list);
+       spin_unlock(&sn_irq_info_lock);
+       call_rcu(&sn_irq_info->rcu, sn_irq_info_free);
+
+       pci_dev_put(pci_dev);
+}
+
 static void force_interrupt(int irq)
 {
        struct sn_irq_info *sn_irq_info;
 
        if (!sn_ioif_inited)
                return;
-       sn_irq_info = sn_irq[irq];
-       while (sn_irq_info) {
+
+       rcu_read_lock();
+       list_for_each_entry_rcu(sn_irq_info, sn_irq_lh[irq], list) {
                if (IS_PCI_BRIDGE_ASIC(sn_irq_info->irq_bridge_type) &&
-                   (sn_irq_info->irq_bridge != NULL)) {
+                   (sn_irq_info->irq_bridge != NULL))
                        pcibr_force_interrupt(sn_irq_info);
-               }
-               sn_irq_info = sn_irq_info->irq_next;
        }
+       rcu_read_unlock();
 }
 
 /*
@@ -402,19 +396,41 @@ static void sn_check_intr(int irq, struct sn_irq_info *sn_irq_info)
 
 void sn_lb_int_war_check(void)
 {
+       struct sn_irq_info *sn_irq_info;
        int i;
 
        if (!sn_ioif_inited || pda->sn_first_irq == 0)
                return;
+
+       rcu_read_lock();
        for (i = pda->sn_first_irq; i <= pda->sn_last_irq; i++) {
-               struct sn_irq_info *sn_irq_info = sn_irq[i];
-               while (sn_irq_info) {
-                       /* Only call for PCI bridges that are fully initialized. */
+               list_for_each_entry_rcu(sn_irq_info, sn_irq_lh[i], list) {
+                       /*
+                        * Only call for PCI bridges that are fully
+                        * initialized.
+                        */
                        if (IS_PCI_BRIDGE_ASIC(sn_irq_info->irq_bridge_type) &&
-                           (sn_irq_info->irq_bridge != NULL)) {
+                           (sn_irq_info->irq_bridge != NULL))
                                sn_check_intr(i, sn_irq_info);
-                       }
-                       sn_irq_info = sn_irq_info->irq_next;
                }
        }
+       rcu_read_unlock();
+}
+
+void sn_irq_lh_init(void)
+{
+       int i;
+
+       sn_irq_lh = kmalloc(sizeof(struct list_head *) * NR_IRQS, GFP_KERNEL);
+       if (!sn_irq_lh)
+               panic("SN PCI INIT: Failed to allocate memory for PCI init\n");
+
+       for (i = 0; i < NR_IRQS; i++) {
+               sn_irq_lh[i] = kmalloc(sizeof(struct list_head), GFP_KERNEL);
+               if (!sn_irq_lh[i])
+                       panic("SN PCI INIT: Failed IRQ memory allocation\n");
+
+               INIT_LIST_HEAD(sn_irq_lh[i]);
+       }
+
 }
index e51471f..e190dd4 100644 (file)
@@ -9,6 +9,8 @@
 #ifndef _ASM_IA64_SN_INTR_H
 #define _ASM_IA64_SN_INTR_H
 
+#include <linux/rcupdate.h>
+
 #define SGI_UART_VECTOR                (0xe9)
 #define SGI_PCIBR_ERROR                (0x33)
 
@@ -33,7 +35,7 @@
 
 // The SN PROM irq struct
 struct sn_irq_info {
-       struct sn_irq_info *irq_next;   /* sharing irq list          */
+       struct sn_irq_info *irq_next;   /* deprecated DO NOT USE     */
        short           irq_nasid;      /* Nasid IRQ is assigned to  */
        int             irq_slice;      /* slice IRQ is assigned to  */
        int             irq_cpuid;      /* kernel logical cpuid      */
@@ -47,6 +49,8 @@ struct sn_irq_info {
        int             irq_cookie;     /* unique cookie             */
        int             irq_flags;      /* flags */
        int             irq_share_cnt;  /* num devices sharing IRQ   */
+       struct list_head        list;   /* list of sn_irq_info structs */
+       struct rcu_head         rcu;    /* rcu callback list */
 };
 
 extern void sn_send_IPI_phys(int, long, int, int);
index ed4031d..42aea21 100644 (file)
@@ -10,8 +10,6 @@
 
 #include <linux/pci.h>
 
-extern struct sn_irq_info **sn_irq;
-
 #define SN_PCIDEV_INFO(pci_dev) \
         ((struct pcidev_info *)(pci_dev)->sysdata)
 
@@ -50,9 +48,11 @@ struct pcidev_info {
 
        struct sn_irq_info      *pdi_sn_irq_info;
        struct sn_pcibus_provider *pdi_provider;        /* sn pci ops */
+       struct pci_dev          *host_pci_dev;          /* host bus link */
 };
 
 extern void sn_irq_fixup(struct pci_dev *pci_dev,
                         struct sn_irq_info *sn_irq_info);
 
+extern void sn_irq_lh_init(void);
 #endif                         /* _ASM_IA64_SN_PCI_PCIDEV_H */