MIPS: BCM63XX: recognize Cable Modem firmware format

Add the firmware header format which is used by Broadcom Cable Modem
SoCs such as the BCM3368 SoC. We export the bcm_hcs firmware format
structure because it is used by user-land tools to create firmware
images for these SoCs and will later be used by a corresponding MTD
parser.
Signed-off-by: Florian Fainelli <florian@openwrt.org>
Cc: linux-mips@linux-mips.org
Cc: cernekee@gmail.com
Cc: jogo@openwrt.org
Patchwork: https://patchwork.linux-mips.org/patch/5496/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/bcm63xx/boards/board_bcm963xx.c

@@ -28,8 +28,12 @@
 #include <bcm63xx_dev_usb_usbd.h>
 #include <board_bcm963xx.h>
 
+#include <uapi/linux/bcm933xx_hcs.h>
+
 #define PFX	"board_bcm963xx: "
 
+#define HCS_OFFSET_128K			0x20000
+
 static struct board_info board;
 
 /*
@@ -722,8 +726,9 @@ void __init board_prom_init(void)
 	unsigned int i;
 	u8 *boot_addr, *cfe;
 	char cfe_version[32];
-	char *board_name;
+	char *board_name = NULL;
 	u32 val;
+	struct bcm_hcs *hcs;
 
 	/* read base address of boot chip select (0)
 	 * 6328/6362 do not have MPI but boot from a fixed address
@@ -747,7 +752,12 @@ void __init board_prom_init(void)
 
 	bcm63xx_nvram_init(boot_addr + BCM963XX_NVRAM_OFFSET);
 
-	board_name = bcm63xx_nvram_get_name();
+	if (BCMCPU_IS_3368()) {
+		hcs = (struct bcm_hcs *)boot_addr;
+		board_name = hcs->filename;
+	} else {
+		board_name = bcm63xx_nvram_get_name();
+	}
 	/* find board by name */
 	for (i = 0; i < ARRAY_SIZE(bcm963xx_boards); i++) {
 		if (strncmp(board_name, bcm963xx_boards[i]->name, 16))

include/uapi/linux/Kbuild

@@ -62,6 +62,7 @@ header-y += auxvec.h
 header-y += ax25.h
 header-y += b1lli.h
 header-y += baycom.h
+header-y += bcm933xx_hcs.h
 header-y += bfs_fs.h
 header-y += binfmts.h
 header-y += blkpg.h

include/uapi/linux/bcm933xx_hcs.h

+/*
+ * Broadcom Cable Modem firmware format
+ */
+
+#ifndef __BCM933XX_HCS_H
+#define __BCM933XX_HCS_H
+
+#include <linux/types.h>
+
+struct bcm_hcs {
+	__u16 magic;
+	__u16 control;
+	__u16 rev_maj;
+	__u16 rev_min;
+	__u32 build_date;
+	__u32 filelen;
+	__u32 ldaddress;
+	char filename[64];
+	__u16 hcs;
+	__u16 her_znaet_chto;
+	__u32 crc;
+};
+
+#endif /* __BCM933XX_HCS */