armv8: semihosting: add a command to load semihosted images

Instead of sprinkling custom code and calls over the Vexpress64
boardfile, create a command that loads images using semihosting
just like we would load from flash memory of over the network,
using a special command:

    smhload <image> <address>

This will make it possible to remove some custom calls and
code and make the boot easier.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

diff --git a/arch/arm/lib/semihosting.c b/arch/arm/lib/semihosting.c
index d3f724b726e19da7004ecabdc5ff38512a7df63a..edacb11877319342b1bf8cd0ac9c2d8cd4c97226 100644 (file)
--- a/arch/arm/lib/semihosting.c
+++ b/arch/arm/lib/semihosting.c
@@ -13,6 +13,7 @@
  * for them.
  */
 #include <common.h>
+#include <command.h>
 #include <asm/semihosting.h>
 
 #define SYSOPEN                0x01
@@ -234,3 +235,72 @@ long smh_len(const char *fname)
        /* Return the file length (or -1 error indication) */
        return len;
 }
+
+static int smh_load_file(const char * const name, ulong load_addr,
+                        ulong *end_addr)
+{
+       long fd;
+       long len;
+       long ret;
+
+       fd = smh_open(name, "rb");
+       if (fd == -1)
+               return -1;
+
+       len = smh_len_fd(fd);
+       if (len < 0) {
+               smh_close(fd);
+               return -1;
+       }
+
+       ret = smh_read(fd, (void *)load_addr, len);
+       smh_close(fd);
+
+       if (ret == 0) {
+               *end_addr = load_addr + len - 1;
+               printf("loaded file %s from %08lX to %08lX, %08lX bytes\n",
+                      name,
+                      load_addr,
+                      *end_addr,
+                      len);
+       } else {
+               printf("read failed\n");
+               return 0;
+       }
+
+       return 0;
+}
+
+static int do_smhload(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
+{
+       if (argc == 3 || argc == 4) {
+               ulong load_addr;
+               ulong end_addr = 0;
+               ulong ret;
+               char end_str[64];
+
+               load_addr = simple_strtoul(argv[2], NULL, 16);
+               if (!load_addr)
+                       return -1;
+
+               ret = smh_load_file(argv[1], load_addr, &end_addr);
+               if (ret < 0)
+                       return 1;
+
+               /* Optionally save returned end to the environment */
+               if (argc == 4) {
+                       sprintf(end_str, "0x%08lx", end_addr);
+                       setenv(argv[3], end_str);
+               }
+       } else {
+               return CMD_RET_USAGE;
+       }
+       return 0;
+}
+
+U_BOOT_CMD(smhload, 4, 0, do_smhload, "load a file using semihosting",
+          "<file> 0x<address> [end var]\n"
+          "    - load a semihosted file to the address specified\n"
+          "      if the optional [end var] is specified, the end\n"
+          "      address of the file will be stored in this environment\n"
+          "      variable.\n");

diff --git a/doc/README.semihosting b/doc/README.semihosting
index 7248560780694cf797e0cefeb1659ce99a19376e..c016a4f8406d3e2b1151a986cfb7e300535321cf 100644 (file)
--- a/doc/README.semihosting
+++ b/doc/README.semihosting
@@ -30,25 +30,10 @@ vexpress_aemv8a.h but differentiate the two models by the presence or
 absence of CONFIG_BASE_FVP. This change is tested and works on both the
 Foundation and Base fastmodel simulators.
 
-The level of semihosting support is minimal, restricted to just what it
-takes to load images to memory. If more semihosting functionality is
-required, such as file seek, outputting strings, reading characters, etc,
-then it can be easily added later.
+The semihosting code adds a command:
 
-We require that the board include file define these env variables:
-- kernel_name          e.g. "uImage"
-- kernel_addr_r                e.g. "0x80000000"
-- initrd_name          e.g. "ramdisk.img"
-- initrd_addr_r                e.g. "0x88000000"
-- fdt_name             e.g. "devtree.dtb"
-- fdt_addr_r           e.g. "0x83000000"
+  smhload <image> <address> [env var]
 
-Optionally, "fdt_high" and "initrd_high" can be specified as per
-their rules for allowing or preventing copying of these images.
-
-For the "fdt chosen" startup macro, this code will then define:
-- initrd_end (based on retrieving initrd_addr_r plus actual initrd_size)
-
-We will then load the kernel, initrd, and fdt into the specified
-locations in memory in a similar way that the ATF fastmodel code
-uses semihosting calls to load other boot stages and u-boot itself.
+That will load an image from the host filesystem into RAM at the specified
+address and optionally store the load end address in the specified
+environment variable.