mtd/ps3vram: Add ps3vram driver for accessing video RAM as MTD

Add ps3vram driver, which exposes unused video RAM on the PS3 as a MTD
device suitable for storage or swap.  Fast data transfer is achieved
using a local cache in system RAM and DMA transfers via the GPU.

Signed-off-by: Vivien Chappelier <vivien.chappelier@free.fr>
Signed-off-by: Jim Paris <jim@jtan.com>
Acked-by: Geoff Levand <geoffrey.levand@am.sony.com>
Acked-by: David Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

2 files changed, 38 insertions, 0 deletions

diff --git a/arch/powerpc/include/asm/ps3.h b/arch/powerpc/include/asm/ps3.h
index cff30c0ef1ff..66b650532adf 100644
--- a/arch/powerpc/include/asm/ps3.h
+++ b/arch/powerpc/include/asm/ps3.h
@@ -320,6 +320,7 @@ enum ps3_match_id {
 
 enum ps3_match_sub_id {
         PS3_MATCH_SUB_ID_GPU_FB         = 1,
+        PS3_MATCH_SUB_ID_GPU_RAMDISK    = 2,
 };
 
 #define PS3_MODULE_ALIAS_EHCI           "ps3:1:0"
diff --git a/arch/powerpc/platforms/ps3/device-init.c b/arch/powerpc/platforms/ps3/device-init.c
index dbc124e05646..ca71a12b764c 100644
--- a/arch/powerpc/platforms/ps3/device-init.c
+++ b/arch/powerpc/platforms/ps3/device-init.c
@@ -518,6 +518,41 @@ fail_device_register:
         return result;
 }
 
+static int __init ps3_register_ramdisk_device(void)
+{
+        int result;
+        struct layout {
+                struct ps3_system_bus_device dev;
+        } *p;
+
+        pr_debug(" -> %s:%d\n", __func__, __LINE__);
+
+        p = kzalloc(sizeof(struct layout), GFP_KERNEL);
+
+        if (!p)
+                return -ENOMEM;
+
+        p->dev.match_id = PS3_MATCH_ID_GPU;
+        p->dev.match_sub_id = PS3_MATCH_SUB_ID_GPU_RAMDISK;
+        p->dev.dev_type = PS3_DEVICE_TYPE_IOC0;
+
+        result = ps3_system_bus_device_register(&p->dev);
+
+        if (result) {
+                pr_debug("%s:%d ps3_system_bus_device_register failed\n",
+                        __func__, __LINE__);
+                goto fail_device_register;
+        }
+
+        pr_debug(" <- %s:%d\n", __func__, __LINE__);
+        return 0;
+
+fail_device_register:
+        kfree(p);
+        pr_debug(" <- %s:%d failed\n", __func__, __LINE__);
+        return result;
+}
+
 /**
  * ps3_setup_dynamic_device - Setup a dynamic device from the repository
  */
@@ -946,6 +981,8 @@ static int __init ps3_register_devices(void)
 
         ps3_register_lpm_devices();
 
+        ps3_register_ramdisk_device();
+
         pr_debug(" <- %s:%d\n", __func__, __LINE__);
         return 0;
 }