spl: semihosting: Don't close fd before spl_load_simple_fit

On real hardware, semihosting calls tend to have a large constant
overhead (on the order of tens of milliseconds). Reduce the number of
calls by one by reusing the existing fd in smh_fit_read, and closing it
at the end of spl_smh_load_image.

Signed-off-by: Sean Anderson <seanga2@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

diff --git a/common/spl/spl_semihosting.c b/common/spl/spl_semihosting.c
index f7dd289286d442dc258faffbea017e8f11b313d9..8f11c29913f20d2b443ed6a31f64176ad3045002 100644 (file)
--- a/common/spl/spl_semihosting.c
+++ b/common/spl/spl_semihosting.c
@@ -24,18 +24,14 @@ static int smh_read_full(long fd, void *memp, size_t len)
 static ulong smh_fit_read(struct spl_load_info *load, ulong file_offset,
                          ulong size, void *buf)
 {
-       long fd;
+       long fd = *(long *)load->priv;
        ulong ret;
 
-       fd = smh_open(load->filename, MODE_READ | MODE_BINARY);
-       if (fd < 0) {
-               log_debug("could not open %s: %ld\n", load->filename, fd);
+       if (smh_seek(fd, file_offset))
                return 0;
-       }
-       ret = smh_read(fd, buf, size);
-       smh_close(fd);
 
-       return ret;
+       ret = smh_read(fd, buf, size);
+       return ret < 0 ? 0 : ret;
 }
 
 static int spl_smh_load_image(struct spl_image_info *spl_image,
@@ -73,11 +69,11 @@ static int spl_smh_load_image(struct spl_image_info *spl_image,
                debug("Found FIT\n");
                load.read = smh_fit_read;
                load.bl_len = 1;
-               load.filename = filename;
-               load.priv = NULL;
-               smh_close(fd);
+               load.filename = NULL;
+               load.priv = &fd;
 
-               return spl_load_simple_fit(spl_image, &load, 0, header);
+               ret = spl_load_simple_fit(spl_image, &load, 0, header);
+               goto out;
        }
 
        ret = spl_parse_image_header(spl_image, bootdev, header);