s390/ap: configuration information exploitation

Query AP configuration information. Improve performance of AP bus
scans by skipping AP device probing, if the AP deviec is not
configured.

Reviewed-by: Ingo Tuchscherer <ingo.tuchscherer@linux.vnet.ibm.com>
Signed-off-by: Holger Dengler <hd@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 128 insertions, 15 deletions

diff --git a/drivers/s390/crypto/ap_bus.c b/drivers/s390/crypto/ap_bus.c
index ae258a4b4e5e..047c7327b1b4 100644
--- a/drivers/s390/crypto/ap_bus.c
+++ b/drivers/s390/crypto/ap_bus.c
@@ -1,5 +1,5 @@
 /*
- * Copyright IBM Corp. 2006
+ * Copyright IBM Corp. 2006, 2012
  * Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
  *            Martin Schwidefsky <schwidefsky@de.ibm.com>
  *            Ralph Wuerthner <rwuerthn@de.ibm.com>
@@ -62,13 +62,14 @@ static void ap_interrupt_handler(void *unused1, void *unused2);
 static void ap_reset(struct ap_device *ap_dev);
 static void ap_config_timeout(unsigned long ptr);
 static int ap_select_domain(void);
+static void ap_query_configuration(void);
 
 /*
  * Module description.
  */
 MODULE_AUTHOR("IBM Corporation");
-MODULE_DESCRIPTION("Adjunct Processor Bus driver, "
-                   "Copyright IBM Corp. 2006");
+MODULE_DESCRIPTION("Adjunct Processor Bus driver, " \
+                   "Copyright IBM Corp. 2006, 2012");
 MODULE_LICENSE("GPL");
 
 /*
@@ -84,6 +85,7 @@ module_param_named(poll_thread, ap_thread_flag, int, 0000);
 MODULE_PARM_DESC(poll_thread, "Turn on/off poll thread, default is 0 (off).");
 
 static struct device *ap_root_device = NULL;
+static struct ap_config_info *ap_configuration;
 static DEFINE_SPINLOCK(ap_device_list_lock);
 static LIST_HEAD(ap_device_list);
 
@@ -158,6 +160,17 @@ static int ap_interrupts_available(void)
 }
 
 /**
+ * ap_configuration_available(): Test if AP configuration
+ * information is available.
+ *
+ * Returns 1 if AP configuration information is available.
+ */
+static int ap_configuration_available(void)
+{
+        return test_facility(2) && test_facility(12);
+}
+
+/**
  * ap_test_queue(): Test adjunct processor queue.
  * @qid: The AP queue number
  * @queue_depth: Pointer to queue depth value
@@ -242,6 +255,26 @@ __ap_query_functions(ap_qid_t qid, unsigned int *functions)
 }
 #endif
 
+#ifdef CONFIG_64BIT
+static inline int __ap_query_configuration(struct ap_config_info *config)
+{
+        register unsigned long reg0 asm ("0") = 0x04000000UL;
+        register unsigned long reg1 asm ("1") = -EINVAL;
+        register unsigned char *reg2 asm ("2") = (unsigned char *)config;
+
+        asm volatile(
+                ".long 0xb2af0000\n"            /* PQAP(QCI) */
+                "0: la    %1,0\n"
+                "1:\n"
+                EX_TABLE(0b, 1b)
+                : "+d" (reg0), "+d" (reg1), "+d" (reg2)
+                :
+                : "cc");
+
+        return reg1;
+}
+#endif
+
 /**
  * ap_query_functions(): Query supported functions.
  * @qid: The AP queue number
@@ -305,8 +338,8 @@ int ap_4096_commands_available(ap_qid_t qid)
         if (ap_query_functions(qid, &functions))
                 return 0;
 
-        return test_ap_facility(functions, 1) &&
-               test_ap_facility(functions, 2);
+        return ap_test_bit(&functions, 1) &&
+               ap_test_bit(&functions, 2);
 }
 EXPORT_SYMBOL(ap_4096_commands_available);
 
@@ -772,6 +805,7 @@ static int ap_bus_resume(struct device *dev)
                 ap_suspend_flag = 0;
                 if (!ap_interrupts_available())
                         ap_interrupt_indicator = NULL;
+                ap_query_configuration();
                 if (!user_set_domain) {
                         ap_domain_index = -1;
                         ap_select_domain();
@@ -997,6 +1031,65 @@ static struct bus_attribute *const ap_bus_attrs[] = {
         NULL,
 };
 
+static inline int ap_test_config(unsigned int *field, unsigned int nr)
+{
+        if (nr > 0xFFu)
+                return 0;
+        return ap_test_bit((field + (nr >> 5)), (nr & 0x1f));
+}
+
+/*
+ * ap_test_config_card_id(): Test, whether an AP card ID is configured.
+ * @id AP card ID
+ *
+ * Returns 0 if the card is not configured
+ *         1 if the card is configured or
+ *           if the configuration information is not available
+ */
+static inline int ap_test_config_card_id(unsigned int id)
+{
+        if (!ap_configuration)
+                return 1;
+        return ap_test_config(ap_configuration->apm, id);
+}
+
+/*
+ * ap_test_config_domain(): Test, whether an AP usage domain is configured.
+ * @domain AP usage domain ID
+ *
+ * Returns 0 if the usage domain is not configured
+ *         1 if the usage domain is configured or
+ *           if the configuration information is not available
+ */
+static inline int ap_test_config_domain(unsigned int domain)
+{
+        if (!ap_configuration)
+                return 1;
+        return ap_test_config(ap_configuration->aqm, domain);
+}
+
+/**
+ * ap_query_configuration(): Query AP configuration information.
+ *
+ * Query information of installed cards and configured domains from AP.
+ */
+static void ap_query_configuration(void)
+{
+#ifdef CONFIG_64BIT
+        if (ap_configuration_available()) {
+                if (!ap_configuration)
+                        ap_configuration =
+                                kzalloc(sizeof(struct ap_config_info),
+                                        GFP_KERNEL);
+                if (ap_configuration)
+                        __ap_query_configuration(ap_configuration);
+        } else
+                ap_configuration = NULL;
+#else
+        ap_configuration = NULL;
+#endif
+}
+
 /**
  * ap_select_domain(): Select an AP domain.
  *
@@ -1005,6 +1098,7 @@ static struct bus_attribute *const ap_bus_attrs[] = {
 static int ap_select_domain(void)
 {
         int queue_depth, device_type, count, max_count, best_domain;
+        ap_qid_t qid;
         int rc, i, j;
 
         /*
@@ -1018,9 +1112,13 @@ static int ap_select_domain(void)
         best_domain = -1;
         max_count = 0;
         for (i = 0; i < AP_DOMAINS; i++) {
+                if (!ap_test_config_domain(i))
+                        continue;
                 count = 0;
                 for (j = 0; j < AP_DEVICES; j++) {
-                        ap_qid_t qid = AP_MKQID(j, i);
+                        if (!ap_test_config_card_id(j))
+                                continue;
+                        qid = AP_MKQID(j, i);
                         rc = ap_query_queue(qid, &queue_depth, &device_type);
                         if (rc)
                                 continue;
@@ -1169,6 +1267,7 @@ static void ap_scan_bus(struct work_struct *unused)
         unsigned int device_functions;
         int rc, i;
 
+        ap_query_configuration();
         if (ap_select_domain() != 0)
                 return;
         for (i = 0; i < AP_DEVICES; i++) {
@@ -1176,7 +1275,10 @@ static void ap_scan_bus(struct work_struct *unused)
                 dev = bus_find_device(&ap_bus_type, NULL,
                                       (void *)(unsigned long)qid,
                                       __ap_scan_bus);
-                rc = ap_query_queue(qid, &queue_depth, &device_type);
+                if (ap_test_config_card_id(i))
+                        rc = ap_query_queue(qid, &queue_depth, &device_type);
+                else
+                        rc = -ENODEV;
                 if (dev) {
                         if (rc == -EBUSY) {
                                 set_current_state(TASK_UNINTERRUPTIBLE);
@@ -1227,9 +1329,9 @@ static void ap_scan_bus(struct work_struct *unused)
                                 kfree(ap_dev);
                                 continue;
                         }
-                        if (test_ap_facility(device_functions, 3))
+                        if (ap_test_bit(&device_functions, 3))
                                 ap_dev->device_type = AP_DEVICE_TYPE_CEX3C;
-                        else if (test_ap_facility(device_functions, 4))
+                        else if (ap_test_bit(&device_functions, 4))
                                 ap_dev->device_type = AP_DEVICE_TYPE_CEX3A;
                         else {
                                 kfree(ap_dev);
@@ -1785,6 +1887,7 @@ int __init ap_module_init(void)
                 goto out_root;
         }
 
+        ap_query_configuration();
         if (ap_select_domain() == 0)
                 ap_scan_bus(NULL);
 
diff --git a/drivers/s390/crypto/ap_bus.h b/drivers/s390/crypto/ap_bus.h
index 52d61995af88..5018f66dada5 100644
--- a/drivers/s390/crypto/ap_bus.h
+++ b/drivers/s390/crypto/ap_bus.h
@@ -1,5 +1,5 @@
 /*
- * Copyright IBM Corp. 2006
+ * Copyright IBM Corp. 2006, 2012
  * Author(s): Cornelia Huck <cornelia.huck@de.ibm.com>
  *            Martin Schwidefsky <schwidefsky@de.ibm.com>
  *            Ralph Wuerthner <rwuerthn@de.ibm.com>
@@ -83,13 +83,12 @@ int ap_queue_status_invalid_test(struct ap_queue_status *status)
         return !(memcmp(status, &invalid, sizeof(struct ap_queue_status)));
 }
 
-#define MAX_AP_FACILITY 31
-
-static inline int test_ap_facility(unsigned int function, unsigned int nr)
+#define AP_MAX_BITS 31
+static inline int ap_test_bit(unsigned int *ptr, unsigned int nr)
 {
-        if (nr > MAX_AP_FACILITY)
+        if (nr > AP_MAX_BITS)
                 return 0;
-        return function & (unsigned int)(0x80000000 >> nr);
+        return (*ptr & (0x80000000u >> nr)) != 0;
 }
 
 #define AP_RESPONSE_NORMAL              0x00
@@ -183,6 +182,17 @@ struct ap_message {
                         struct ap_message *);
 };
 
+struct ap_config_info {
+        unsigned int special_command:1;
+        unsigned int ap_extended:1;
+        unsigned char reserved1:6;
+        unsigned char reserved2[15];
+        unsigned int apm[8];            /* AP ID mask */
+        unsigned int aqm[8];            /* AP queue mask */
+        unsigned int adm[8];            /* AP domain mask */
+        unsigned char reserved4[16];
+} __packed;
+
 #define AP_DEVICE(dt)                                   \
         .dev_type=(dt),                                 \
         .match_flags=AP_DEVICE_ID_MATCH_DEVICE_TYPE,