IB/hfi1: Add ability to read platform config from the EPROM

Add a function to read the platform configuration file from
the EPROM.

Reviewed-by: Easwar Hariharan <easwar.hariharan@intel.com>
Signed-off-by: Dean Luick <dean.luick@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>

drivers/infiniband/hw/hfi1/eprom.c

@@ -203,3 +203,85 @@ int eprom_init(struct hfi1_devdata *dd)
 done_asic:
 	return ret;
 }
+
+/* magic character sequence that trails an image */
+#define IMAGE_TRAIL_MAGIC "egamiAPO"
+
+/*
+ * Read all of partition 1.  The actual file is at the front.  Adjust
+ * the returned size if a trailing image magic is found.
+ */
+static int read_partition_platform_config(struct hfi1_devdata *dd, void **data,
+					  u32 *size)
+{
+	void *buffer;
+	void *p;
+	u32 length;
+	int ret;
+
+	buffer = kmalloc(P1_SIZE, GFP_KERNEL);
+	if (!buffer)
+		return -ENOMEM;
+
+	ret = read_length(dd, P1_START, P1_SIZE, buffer);
+	if (ret) {
+		kfree(buffer);
+		return ret;
+	}
+
+	/* scan for image magic that may trail the actual data */
+	p = strnstr(buffer, IMAGE_TRAIL_MAGIC, P1_SIZE);
+	if (p)
+		length = p - buffer;
+	else
+		length = P1_SIZE;
+
+	*data = buffer;
+	*size = length;
+	return 0;
+}
+
+/*
+ * Read the platform configuration file from the EPROM.
+ *
+ * On success, an allocated buffer containing the data and its size are
+ * returned.  It is up to the caller to free this buffer.
+ *
+ * Return value:
+ *   0	      - success
+ *   -ENXIO   - no EPROM is available
+ *   -EBUSY   - not able to acquire access to the EPROM
+ *   -ENOENT  - no recognizable file written
+ *   -ENOMEM  - buffer could not be allocated
+ */
+int eprom_read_platform_config(struct hfi1_devdata *dd, void **data, u32 *size)
+{
+	u32 directory[EP_PAGE_DWORDS]; /* aligned buffer */
+	int ret;
+
+	if (!dd->eprom_available)
+		return -ENXIO;
+
+	ret = acquire_chip_resource(dd, CR_EPROM, EPROM_TIMEOUT);
+	if (ret)
+		return -EBUSY;
+
+	/* read the last page of P0 for the EPROM format magic */
+	ret = read_length(dd, P1_START - EP_PAGE_SIZE, EP_PAGE_SIZE, directory);
+	if (ret)
+		goto done;
+
+	/* last dword of P0 contains a magic indicator */
+	if (directory[EP_PAGE_DWORDS - 1] == 0) {
+		/* partition format */
+		ret = read_partition_platform_config(dd, data, size);
+		goto done;
+	}
+
+	/* nothing recognized */
+	ret = -ENOENT;
+
+done:
+	release_chip_resource(dd, CR_EPROM);
+	return ret;
+}

drivers/infiniband/hw/hfi1/eprom.h

@@ -48,3 +48,5 @@
 struct hfi1_devdata;
 
 int eprom_init(struct hfi1_devdata *dd);
+int eprom_read_platform_config(struct hfi1_devdata *dd, void **buf_ret,
+			       u32 *size_ret);