powerpc/powernv: Create OPAL sglist helper functions and fix endian issues

We have two copies of code that creates an OPAL sg list. Consolidate
these into a common set of helpers and fix the endian issues.

The flash interface embedded a version number in the num_entries
field, whereas the dump interface did did not. Since versioning
wasn't added to the flash interface and it is impossible to add
this in a backwards compatible way, just remove it.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

4 files changed, 76 insertions, 188 deletions

diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h
index 1a752ac8c0ba..afb0fedd1214 100644
--- a/arch/powerpc/include/asm/opal.h
+++ b/arch/powerpc/include/asm/opal.h
@@ -41,14 +41,14 @@ struct opal_takeover_args {
  * size except the last one in the list to be as well.
  */
 struct opal_sg_entry {
-        void    *data;
-        long    length;
+        __be64 data;
+        __be64 length;
 };
 
-/* sg list */
+/* SG list */
 struct opal_sg_list {
-        unsigned long num_entries;
-        struct opal_sg_list *next;
+        __be64 length;
+        __be64 next;
         struct opal_sg_entry entry[];
 };
 
@@ -929,6 +929,10 @@ extern int opal_resync_timebase(void);
 
 extern void opal_lpc_init(void);
 
+struct opal_sg_list *opal_vmalloc_to_sg_list(void *vmalloc_addr,
+                                             unsigned long vmalloc_size);
+void opal_free_sg_list(struct opal_sg_list *sg);
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* __OPAL_H */
diff --git a/arch/powerpc/platforms/powernv/opal-dump.c b/arch/powerpc/platforms/powernv/opal-dump.c
index b9827b0d87e4..f0b472427c57 100644
--- a/arch/powerpc/platforms/powernv/opal-dump.c
+++ b/arch/powerpc/platforms/powernv/opal-dump.c
@@ -209,80 +209,6 @@ static struct kobj_type dump_ktype = {
         .default_attrs = dump_default_attrs,
 };
 
-static void free_dump_sg_list(struct opal_sg_list *list)
-{
-        struct opal_sg_list *sg1;
-        while (list) {
-                sg1 = list->next;
-                kfree(list);
-                list = sg1;
-        }
-        list = NULL;
-}
-
-static struct opal_sg_list *dump_data_to_sglist(struct dump_obj *dump)
-{
-        struct opal_sg_list *sg1, *list = NULL;
-        void *addr;
-        int64_t size;
-
-        addr = dump->buffer;
-        size = dump->size;
-
-        sg1 = kzalloc(PAGE_SIZE, GFP_KERNEL);
-        if (!sg1)
-                goto nomem;
-
-        list = sg1;
-        sg1->num_entries = 0;
-        while (size > 0) {
-                /* Translate virtual address to physical address */
-                sg1->entry[sg1->num_entries].data =
-                        (void *)(vmalloc_to_pfn(addr) << PAGE_SHIFT);
-
-                if (size > PAGE_SIZE)
-                        sg1->entry[sg1->num_entries].length = PAGE_SIZE;
-                else
-                        sg1->entry[sg1->num_entries].length = size;
-
-                sg1->num_entries++;
-                if (sg1->num_entries >= SG_ENTRIES_PER_NODE) {
-                        sg1->next = kzalloc(PAGE_SIZE, GFP_KERNEL);
-                        if (!sg1->next)
-                                goto nomem;
-
-                        sg1 = sg1->next;
-                        sg1->num_entries = 0;
-                }
-                addr += PAGE_SIZE;
-                size -= PAGE_SIZE;
-        }
-        return list;
-
-nomem:
-        pr_err("%s : Failed to allocate memory\n", __func__);
-        free_dump_sg_list(list);
-        return NULL;
-}
-
-static void sglist_to_phy_addr(struct opal_sg_list *list)
-{
-        struct opal_sg_list *sg, *next;
-
-        for (sg = list; sg; sg = next) {
-                next = sg->next;
-                /* Don't translate NULL pointer for last entry */
-                if (sg->next)
-                        sg->next = (struct opal_sg_list *)__pa(sg->next);
-                else
-                        sg->next = NULL;
-
-                /* Convert num_entries to length */
-                sg->num_entries =
-                        sg->num_entries * sizeof(struct opal_sg_entry) + 16;
-        }
-}
-
 static int64_t dump_read_info(uint32_t *id, uint32_t *size, uint32_t *type)
 {
         int rc;
@@ -314,15 +240,12 @@ static int64_t dump_read_data(struct dump_obj *dump)
         }
 
         /* Generate SG list */
-        list = dump_data_to_sglist(dump);
+        list = opal_vmalloc_to_sg_list(dump->buffer, dump->size);
         if (!list) {
                 rc = -ENOMEM;
                 goto out;
         }
 
-        /* Translate sg list addr to real address */
-        sglist_to_phy_addr(list);
-
         /* First entry address */
         addr = __pa(list);
 
@@ -341,7 +264,7 @@ static int64_t dump_read_data(struct dump_obj *dump)
                         __func__, dump->id);
 
         /* Free SG list */
-        free_dump_sg_list(list);
+        opal_free_sg_list(list);
 
 out:
         return rc;
diff --git a/arch/powerpc/platforms/powernv/opal-flash.c b/arch/powerpc/platforms/powernv/opal-flash.c
index a968fd1888b3..dc487ff04704 100644
--- a/arch/powerpc/platforms/powernv/opal-flash.c
+++ b/arch/powerpc/platforms/powernv/opal-flash.c
@@ -79,9 +79,6 @@
 /* XXX: Assume candidate image size is <= 1GB */
 #define MAX_IMAGE_SIZE  0x40000000
 
-/* Flash sg list version */
-#define SG_LIST_VERSION (1UL)
-
 /* Image status */
 enum {
         IMAGE_INVALID,
@@ -272,93 +269,11 @@ static ssize_t manage_store(struct kobject *kobj,
 }
 
 /*
- * Free sg list
- */
-static void free_sg_list(struct opal_sg_list *list)
-{
-        struct opal_sg_list *sg1;
-        while (list) {
-                sg1 = list->next;
-                kfree(list);
-                list = sg1;
-        }
-        list = NULL;
-}
-
-/*
- * Build candidate image scatter gather list
- *
- * list format:
- *   -----------------------------------
- *  |  VER (8) | Entry length in bytes  |
- *   -----------------------------------
- *  |  Pointer to next entry            |
- *   -----------------------------------
- *  |  Address of memory area 1         |
- *   -----------------------------------
- *  |  Length of memory area 1          |
- *   -----------------------------------
- *  |   .........                       |
- *   -----------------------------------
- *  |   .........                       |
- *   -----------------------------------
- *  |  Address of memory area N         |
- *   -----------------------------------
- *  |  Length of memory area N          |
- *   -----------------------------------
- */
-static struct opal_sg_list *image_data_to_sglist(void)
-{
-        struct opal_sg_list *sg1, *list = NULL;
-        void *addr;
-        int size;
-
-        addr = image_data.data;
-        size = image_data.size;
-
-        sg1 = kzalloc(PAGE_SIZE, GFP_KERNEL);
-        if (!sg1)
-                return NULL;
-
-        list = sg1;
-        sg1->num_entries = 0;
-        while (size > 0) {
-                /* Translate virtual address to physical address */
-                sg1->entry[sg1->num_entries].data =
-                        (void *)(vmalloc_to_pfn(addr) << PAGE_SHIFT);
-
-                if (size > PAGE_SIZE)
-                        sg1->entry[sg1->num_entries].length = PAGE_SIZE;
-                else
-                        sg1->entry[sg1->num_entries].length = size;
-
-                sg1->num_entries++;
-                if (sg1->num_entries >= SG_ENTRIES_PER_NODE) {
-                        sg1->next = kzalloc(PAGE_SIZE, GFP_KERNEL);
-                        if (!sg1->next) {
-                                pr_err("%s : Failed to allocate memory\n",
-                                       __func__);
-                                goto nomem;
-                        }
-
-                        sg1 = sg1->next;
-                        sg1->num_entries = 0;
-                }
-                addr += PAGE_SIZE;
-                size -= PAGE_SIZE;
-        }
-        return list;
-nomem:
-        free_sg_list(list);
-        return NULL;
-}
-
-/*
  * OPAL update flash
  */
 static int opal_flash_update(int op)
 {
-        struct opal_sg_list *sg, *list, *next;
+        struct opal_sg_list *list;
         unsigned long addr;
         int64_t rc = OPAL_PARAMETER;
 
@@ -368,30 +283,13 @@ static int opal_flash_update(int op)
                 goto flash;
         }
 
-        list = image_data_to_sglist();
+        list = opal_vmalloc_to_sg_list(image_data.data, image_data.size);
         if (!list)
                 goto invalid_img;
 
         /* First entry address */
         addr = __pa(list);
 
-        /* Translate sg list address to absolute */
-        for (sg = list; sg; sg = next) {
-                next = sg->next;
-                /* Don't translate NULL pointer for last entry */
-                if (sg->next)
-                        sg->next = (struct opal_sg_list *)__pa(sg->next);
-                else
-                        sg->next = NULL;
-
-                /*
-                 * Convert num_entries to version/length format
-                 * to satisfy OPAL.
-                 */
-                sg->num_entries = (SG_LIST_VERSION << 56) |
-                        (sg->num_entries * sizeof(struct opal_sg_entry) + 16);
-        }
-
         pr_alert("FLASH: Image is %u bytes\n", image_data.size);
         pr_alert("FLASH: Image update requested\n");
         pr_alert("FLASH: Image will be updated during system reboot\n");
diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c
index 17cfc70082aa..360ad80c754c 100644
--- a/arch/powerpc/platforms/powernv/opal.c
+++ b/arch/powerpc/platforms/powernv/opal.c
@@ -638,3 +638,66 @@ void opal_shutdown(void)
 
 /* Export this so that test modules can use it */
 EXPORT_SYMBOL_GPL(opal_invalid_call);
+
+/* Convert a region of vmalloc memory to an opal sg list */
+struct opal_sg_list *opal_vmalloc_to_sg_list(void *vmalloc_addr,
+                                             unsigned long vmalloc_size)
+{
+        struct opal_sg_list *sg, *first = NULL;
+        unsigned long i = 0;
+
+        sg = kzalloc(PAGE_SIZE, GFP_KERNEL);
+        if (!sg)
+                goto nomem;
+
+        first = sg;
+
+        while (vmalloc_size > 0) {
+                uint64_t data = vmalloc_to_pfn(vmalloc_addr) << PAGE_SHIFT;
+                uint64_t length = min(vmalloc_size, PAGE_SIZE);
+
+                sg->entry[i].data = cpu_to_be64(data);
+                sg->entry[i].length = cpu_to_be64(length);
+                i++;
+
+                if (i >= SG_ENTRIES_PER_NODE) {
+                        struct opal_sg_list *next;
+
+                        next = kzalloc(PAGE_SIZE, GFP_KERNEL);
+                        if (!next)
+                                goto nomem;
+
+                        sg->length = cpu_to_be64(
+                                        i * sizeof(struct opal_sg_entry) + 16);
+                        i = 0;
+                        sg->next = cpu_to_be64(__pa(next));
+                        sg = next;
+                }
+
+                vmalloc_addr += length;
+                vmalloc_size -= length;
+        }
+
+        sg->length = cpu_to_be64(i * sizeof(struct opal_sg_entry) + 16);
+
+        return first;
+
+nomem:
+        pr_err("%s : Failed to allocate memory\n", __func__);
+        opal_free_sg_list(first);
+        return NULL;
+}
+
+void opal_free_sg_list(struct opal_sg_list *sg)
+{
+        while (sg) {
+                uint64_t next = be64_to_cpu(sg->next);
+
+                kfree(sg);
+
+                if (next)
+                        sg = __va(next);
+                else
+                        sg = NULL;
+        }
+}