Fix loading kernel from official vendor firmware

As it turned out, some old kernel versions from Atheros LSDK expect
different arguments passed from bootloader: RAM size (in bytes) in 3rd
parameter and FLASH size (in MB) in 4th.

Most of TP-Link firmware also contains kernel which follows this
'broken' approach.

To make fix more universal, load kernel with different parameters and
their values based on 'lsdk_kernel' environment variable. If it's > 0,
RAM and FLASH size will be passed to satisfy LSDK based kernel
requirements.

diff --git a/u-boot/lib_mips/mips_linux.c b/u-boot/lib_mips/mips_linux.c
index 4f161260491f199fd87b3b83c9513faa43171a49..bf35cbc0be962ed6f12e59ad7d7c1144980d0f05 100644 (file)
--- a/u-boot/lib_mips/mips_linux.c
+++ b/u-boot/lib_mips/mips_linux.c
@@ -146,20 +146,18 @@ static void linux_env_set(char *env_name, char *env_val)
 
 void do_bootm_linux(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
 {
-       char buf[16];
-       char *cmdline;
-       unsigned int flash_mb;
+       int lsdk_kernel;
+       char *cmdline, *s, buf[16];
        image_header_t *hdr = &header;
-       void(*theKernel)(int, char **, char **, int);
+       void(*Kernel)(int, char **, char **);
+       void(*LSDKKernel)(int, char **, ulong, ulong);
 
        cmdline = getenv("bootargs");
 
-       theKernel = (void (*)(int, char **, char **, int))ntohl(hdr->ih_ep);
-
 #if defined(DEBUG)
-       printf("## Bootargs: %s\n", cmdline);
-       printf("## Transferring control to Linux (at address %08lx) ...\n",
-              (ulong)theKernel);
+       printf("## Bootargs: '%s'\n", cmdline);
+       printf("## Transferring control to Linux (at address 0x%08lx) ...\n",
+              (ulong)(ntohl(hdr->ih_ep)));
 #endif
 
        linux_params_init(UNCACHED_SDRAM(gd->bd->bi_boot_params), cmdline);
@@ -190,7 +188,28 @@ void do_bootm_linux(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
                      (ar7240_reg_rd(AR7240_GPIO_FUNC) | 0x88));
 #endif
 
-       /* Pass the flash size as expected by current Linux kernel for AR7100 */
-       flash_mb = gd->bd->bi_flashsize >> 20;
-       theKernel(linux_argc, linux_argv, linux_env, flash_mb);
+       /*
+        * In some of old Atheros LSDK based firmware versions (kernel 2.6.x),
+        * kernel expects RAM size (in bytes) in 3rd parameter and FLASH
+        * size (in MB) in 4th. Also, most of old TP-Link firmwares follow
+        * this 'broken' approach.
+        *
+        * To make it somehow universal, we will use here a dedicated env
+        * flag 'lsdk_kernel' - if it's set to > 0, RAM and FLASH sizes
+        * will be passed as 3rd and 4th parameters.
+        */
+       s = getenv("lsdk_kernel");
+       lsdk_kernel = s ? simple_strtol(s, NULL, 10) : 0;
+
+       if (lsdk_kernel > 0) {
+               LSDKKernel = (void (*)(int, char **,
+                                      ulong, ulong))ntohl(hdr->ih_ep);
+
+               LSDKKernel(linux_argc, linux_argv, gd->ram_size,
+                          gd->bd->bi_flashsize >> 20);
+       } else {
+               Kernel = (void (*)(int, char **, char **))ntohl(hdr->ih_ep);
+
+               Kernel(linux_argc, linux_argv, linux_env);
+       }
 }