staging: wfx: allow new PDS format

The device needs data about the antenna configuration. This information
in provided by PDS (Platform Data Set, this is the wording used in WF200
documentation) files.

Until now, the driver had to parse the PDS file before to send it. This
solution was not acceptable for the vanilla kernel. We have slightly
changed the PDS format so it is now an array of Type-Length-Value.

This patch allows to support new format and keep compatibility with
legacy format.

Signed-off-by: Jérôme Pouiller <[e-mail]>
probe: allow new PDS format
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/staging/wfx/main.c

···
 #include "hif_tx_mib.h"
 #include "hif_api_cmd.h"
 
-#define WFX_PDS_MAX_SIZE 1500
+#define WFX_PDS_TLV_TYPE 0x4450 // "PD" (Platform Data) in ascii little-endian
+#define WFX_PDS_MAX_CHUNK_SIZE 1500
 
 MODULE_DESCRIPTION("Silicon Labs 802.11 Wireless LAN driver for WF200");
 MODULE_AUTHOR("Jérôme Pouiller <[e-mail]>");
···
 	return false;
 }
 
-/* The device needs data about the antenna configuration. This information in provided by PDS
- * (Platform Data Set, this is the wording used in WF200 documentation) files. For hardware
- * integrators, the full process to create PDS files is described here:
- *   https:github.com/SiliconLabs/wfx-firmware/blob/master/PDS/README.md
- *
- * So this function aims to send PDS to the device. However, the PDS file is often bigger than Rx
- * buffers of the chip, so it has to be sent in multiple parts.
+/* In legacy format, the PDS file is often bigger than Rx buffers of the chip, so it has to be sent
+ * in multiple parts.
  *
  * In add, the PDS data cannot be split anywhere. The PDS files contains tree structures. Braces are
  * used to enter/leave a level of the tree (in a JSON fashion). PDS files can only been split
  * between root nodes.
  */
-int wfx_send_pds(struct wfx_dev *wdev, u8 *buf, size_t len)
+int wfx_send_pds_legacy(struct wfx_dev *wdev, u8 *buf, size_t len)
 {
 	int ret;
-	int start, brace_level, i;
+	int start = 0, brace_level = 0, i;
 
-	start = 0;
-	brace_level = 0;
-	if (buf[0] != '{') {
-		dev_err(wdev->dev, "valid PDS start with '{'. Did you forget to compress it?\n");
-		return -EINVAL;
-	}
 	for (i = 1; i < len - 1; i++) {
 		if (buf[i] == '{')
 			brace_level++;
···
 			brace_level--;
 		if (buf[i] == '}' && !brace_level) {
 			i++;
-			if (i - start + 1 > WFX_PDS_MAX_SIZE)
+			if (i - start + 1 > WFX_PDS_MAX_CHUNK_SIZE)
 				return -EFBIG;
 			buf[start] = '{';
 			buf[i] = 0;
···
 			buf[i] = ',';
 			start = i;
 		}
+	}
+	return 0;
+}
+
+/* The device needs data about the antenna configuration. This information in provided by PDS
+ * (Platform Data Set, this is the wording used in WF200 documentation) files. For hardware
+ * integrators, the full process to create PDS files is described here:
+ *   https://github.com/SiliconLabs/wfx-firmware/blob/master/PDS/README.md
+ *
+ * The PDS file is an array of Time-Length-Value structs.
+ */
+ int wfx_send_pds(struct wfx_dev *wdev, u8 *buf, size_t len)
+{
+	int ret, chunk_type, chunk_len, chunk_num = 0;
+
+	if (*buf == '{')
+		return wfx_send_pds_legacy(wdev, buf, len);
+	while (len > 0) {
+		chunk_type = get_unaligned_le16(buf + 0);
+		chunk_len = get_unaligned_le16(buf + 2);
+		if (chunk_len > len) {
+			dev_err(wdev->dev, "PDS:%d: corrupted file\n", chunk_num);
+			return -EINVAL;
+		}
+		if (chunk_type != WFX_PDS_TLV_TYPE) {
+			dev_info(wdev->dev, "PDS:%d: skip unknown data\n", chunk_num);
+			goto next;
+		}
+		if (chunk_len > WFX_PDS_MAX_CHUNK_SIZE)
+			dev_warn(wdev->dev, "PDS:%d: unexpectly large chunk\n", chunk_num);
+		if (buf[4] != '{' || buf[chunk_len - 1] != '}')
+			dev_warn(wdev->dev, "PDS:%d: unexpected content\n", chunk_num);
+
+		ret = wfx_hif_configuration(wdev, buf + 4, chunk_len - 4);
+		if (ret > 0) {
+			dev_err(wdev->dev, "PDS:%d: invalid data (unsupported options?)\n", chunk_num);
+			return -EINVAL;
+		}
+		if (ret == -ETIMEDOUT) {
+			dev_err(wdev->dev, "PDS:%d: chip didn't reply (corrupted file?)\n", chunk_num);
+			return ret;
+		}
+		if (ret) {
+			dev_err(wdev->dev, "PDS:%d: chip returned an unknown error\n", chunk_num);
+			return -EIO;
+		}
+next:
+		chunk_num++;
+		len -= chunk_len;
+		buf += chunk_len;
 	}
 	return 0;
 }