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 cff30c0..66b6505 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 dbc124e..ca71a12 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;
 }