First iteration of work to preserve DMA state between executions

6 files changed, 70 insertions, 5 deletions

diff --git a/driver/base.c b/driver/base.c
index 2c3ff23..37102d8 100644
--- a/driver/base.c
+++ b/driver/base.c
@@ -352,6 +352,8 @@ static int __devinit pcidriver_probe(struct pci_dev *pdev, const struct pci_devi
 	INIT_LIST_HEAD(&(privdata->kmem_list));
 	spin_lock_init(&(privdata->kmemlist_lock));
 	atomic_set(&privdata->kmem_count, 0);
+	
+	privdata->kmem_cur = NULL;
 
 	INIT_LIST_HEAD(&(privdata->umem_list));
 	spin_lock_init(&(privdata->umemlist_lock));
diff --git a/driver/common.h b/driver/common.h
index 3bc27d8..e45ae25 100644
--- a/driver/common.h
+++ b/driver/common.h
@@ -16,6 +16,7 @@ typedef struct {
 	unsigned long size;
 	unsigned long type;
 	unsigned long use;
+	unsigned long item;
 	struct class_device_attribute sysfs_attr;	/* initialized when adding the entry */
 } pcidriver_kmem_entry_t;
 
@@ -56,11 +57,13 @@ typedef struct  {
 	struct list_head kmem_list;			/* List of 'kmem_list_entry's associated with this device */
 	atomic_t kmem_count;				/* id for next kmem entry */
 
+	pcidriver_kmem_entry_t *kmem_cur;		/* Currently selected kmem buffer, for mmap */
+	
 	spinlock_t umemlist_lock;			/* Spinlock to lock umem list operations */
 	struct list_head umem_list;			/* List of 'umem_list_entry's associated with this device */
 	atomic_t umem_count;				/* id for next umem entry */
 
-	int msi_mode;
+	int msi_mode;					/* Flag specifying if interrupt have been initialized in MSI mode */
 } pcidriver_privdata_t;
 
 
diff --git a/driver/kmem.c b/driver/kmem.c
index 95a5487..ed2a2af 100644
--- a/driver/kmem.c
+++ b/driver/kmem.c
@@ -35,6 +35,26 @@ int pcidriver_kmem_alloc(pcidriver_privdata_t *privdata, kmem_handle_t *kmem_han
 	pcidriver_kmem_entry_t *kmem_entry;
 	void *retptr;
 
+	privdata->kmem_cur = NULL;
+	
+	if (kmem_handle->reuse) {
+/*	    kmem_entry = pcidriver_kmem_find_entry_use(privdata, kmem_handle->use, kmem_handle->item);
+	    if (kmem_entry) {
+		if (kmem_handle->type != kmem_entry->type) return EINVAL;
+
+		if (kmem_handle->type == PCILIB_KMEM_TYPE_PAGE) kmem_handle->size = kmem_entry->size;
+		else if (kmem_handle->size != kmem_entry->size) return EINVAL;
+
+		kmem_handle->handle_id = kmem_entry->id;
+		kmem_handle->pa = (unsigned long)(kmem_entry->dma_handle);
+		
+		privdata->kmem_cur = kmem_entry;
+
+		return 0;
+	    }*/
+	    kmem_handle->reuse = 0;
+	}
+
 	/* First, allocate zeroed memory for the kmem_entry */
 	if ((kmem_entry = kcalloc(1, sizeof(pcidriver_kmem_entry_t), GFP_KERNEL)) == NULL)
 		goto kmem_alloc_entry_fail;
@@ -42,6 +62,7 @@ int pcidriver_kmem_alloc(pcidriver_privdata_t *privdata, kmem_handle_t *kmem_han
 	/* Initialize the kmem_entry */
 	kmem_entry->id = atomic_inc_return(&privdata->kmem_count) - 1;
 	kmem_entry->use = kmem_handle->use;
+	kmem_entry->item = kmem_handle->item;
 	kmem_entry->type = kmem_handle->type;
 	kmem_handle->handle_id = kmem_entry->id;
 
@@ -102,6 +123,11 @@ int pcidriver_kmem_free( pcidriver_privdata_t *privdata, kmem_handle_t *kmem_han
 {
 	pcidriver_kmem_entry_t *kmem_entry;
 
+	if (kmem_handle->reuse) {
+	    // just mark free
+	    return 0;
+	}
+
 	/* Find the associated kmem_entry for this buffer */
 	if ((kmem_entry = pcidriver_kmem_find_entry(privdata, kmem_handle)) == NULL)
 		return -EINVAL;					/* kmem_handle is not valid */
@@ -193,6 +219,8 @@ int pcidriver_kmem_sync( pcidriver_privdata_t *privdata, kmem_sync_t *kmem_sync
  */
 int pcidriver_kmem_free_entry(pcidriver_privdata_t *privdata, pcidriver_kmem_entry_t *kmem_entry)
 {
+	privdata->kmem_cur = NULL;
+
 	pcidriver_sysfs_remove(privdata, &(kmem_entry->sysfs_attr));
 
 	/* Go over the pages of the kmem buffer, and mark them as not reserved */
@@ -299,6 +327,31 @@ pcidriver_kmem_entry_t *pcidriver_kmem_find_entry_id(pcidriver_privdata_t *privd
 
 /**
  *
+ * find the corresponding kmem_entry for the given use and item.
+ *
+ */
+pcidriver_kmem_entry_t *pcidriver_kmem_find_entry_use(pcidriver_privdata_t *privdata, unsigned long use, unsigned long item)
+{
+	struct list_head *ptr;
+	pcidriver_kmem_entry_t *entry, *result = NULL;
+
+	spin_lock(&(privdata->kmemlist_lock));
+	list_for_each(ptr, &(privdata->kmem_list)) {
+		entry = list_entry(ptr, pcidriver_kmem_entry_t, list);
+
+		if ((entry->use == use)&&(entry->item == item)) {
+			result = entry;
+			break;
+		}
+	}
+
+	spin_unlock(&(privdata->kmemlist_lock));
+	return result;
+}
+
+
+/**
+ *
  * mmap() kernel memory to userspace.
  *
  */
@@ -318,7 +371,8 @@ int pcidriver_mmap_kmem(pcidriver_privdata_t *privdata, struct vm_area_struct *v
 		mod_info("Trying to mmap a kernel memory buffer without creating it first!\n");
 		return -EFAULT;
 	}
-	kmem_entry = list_entry(privdata->kmem_list.prev, pcidriver_kmem_entry_t, list);
+	if (privdata->kmem_cur) kmem_entry = privdata->kmem_cur;
+	else kmem_entry = list_entry(privdata->kmem_list.prev, pcidriver_kmem_entry_t, list);
 	spin_unlock(&(privdata->kmemlist_lock));
 
 	mod_info_dbg("Got kmem_entry with id: %d\n", kmem_entry->id);
diff --git a/driver/kmem.h b/driver/kmem.h
index c9e2fb9..ee12855 100644
--- a/driver/kmem.h
+++ b/driver/kmem.h
@@ -4,4 +4,5 @@ int pcidriver_kmem_sync(  pcidriver_privdata_t *privdata, kmem_sync_t *kmem_sync
 int pcidriver_kmem_free_all(  pcidriver_privdata_t *privdata );
 pcidriver_kmem_entry_t *pcidriver_kmem_find_entry( pcidriver_privdata_t *privdata, kmem_handle_t *kmem_handle );
 pcidriver_kmem_entry_t *pcidriver_kmem_find_entry_id( pcidriver_privdata_t *privdata, int id );
+pcidriver_kmem_entry_t *pcidriver_kmem_find_entry_use(pcidriver_privdata_t *privdata, unsigned long use, unsigned long item);
 int pcidriver_kmem_free_entry( pcidriver_privdata_t *privdata, pcidriver_kmem_entry_t *kmem_entry );
diff --git a/driver/pciDriver.h b/driver/pciDriver.h
index 74eacaf..3ff3357 100644
--- a/driver/pciDriver.h
+++ b/driver/pciDriver.h
@@ -106,6 +106,8 @@ typedef struct {
 	unsigned long size;
 	unsigned long align;
 	unsigned long use;
+	unsigned long item;
+	int reuse;
 	int handle_id;
 } kmem_handle_t;
 
diff --git a/driver/sysfs.c b/driver/sysfs.c
index b082d3c..0653aef 100644
--- a/driver/sysfs.c
+++ b/driver/sysfs.c
@@ -90,14 +90,17 @@ void pcidriver_sysfs_remove(pcidriver_privdata_t *privdata, struct class_device_
 static SYSFS_GET_FUNCTION(pcidriver_show_kmem_entry)
 {
 #if LINUX_VERSION_CODE >= KERNEL_VERSION(2,6,13)
-//	pcidriver_privdata_t *privdata = (pcidriver_privdata_t *)cls->class_data;
+	pcidriver_privdata_t *privdata = SYSFS_GET_PRIVDATA;
 
         /* As we can be sure that attr.name contains a filename which we
          * created (see _pcidriver_sysfs_initialize), we do not need to have
          * sanity checks but can directly call simple_strtol() */
         int id = simple_strtol(attr->attr.name + strlen("kbuf"), NULL, 10);
-
-	return snprintf(buf, PAGE_SIZE, "I am in the kmem_entry show function for buffer %d\n", id);
+	pcidriver_kmem_entry_t *entry = pcidriver_kmem_find_entry_id(privdata, id);
+	if (entry)
+	    return snprintf(buf, PAGE_SIZE, "buffer: %d\ntype: %lu\nuse: 0x%lx\nitem: %lu\nsize: %lu\n", id, entry->type, entry->use, entry->item, entry->size);
+	else
+	    return snprintf(buf, PAGE_SIZE, "I am in the kmem_entry show function for buffer %d\n", id);
 #else
 	return 0;
 #endif