[PATCH 11/16] bootstd: cros: Add a function to read info from partition

[Simon Glass]

The code to read the ChromiumOS information from the partition is
currently all in one function. It reads the entire kernel, which is
unnecessary unless it is to be booted.

Create a new function which reads just the minimum required data from the
disk, then obtains what it needs from there.

For now this function is not used. Future work will plumb it in.

Signed-off-by: Simon Glass <sjg at chromium.org>
---

 boot/bootmeth_cros.c | 121 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 121 insertions(+)

diff --git a/boot/bootmeth_cros.c b/boot/bootmeth_cros.c
index 16a42ad46ae0..82cbdcf2c93a 100644
--- a/boot/bootmeth_cros.c
+++ b/boot/bootmeth_cros.c
@@ -72,6 +72,7 @@ enum {
  * @bootloader_address: Address of bootloader, after body is loaded at
  *	body_load_address
  * @bootloader_size:  Size of bootloader in bytes
+ * @info_buf: Buffer containing ChromiumOS info
  */
 struct cros_priv {
 	ulong body_offset;
@@ -80,6 +81,7 @@ struct cros_priv {
 	ulong body_load_address;
 	ulong bootloader_address;
 	ulong bootloader_size;
+	void *info_buf;
 };
 
 static int cros_check(struct udevice *dev, struct bootflow_iter *iter)
@@ -173,6 +175,125 @@ static int scan_part(struct udevice *blk, int partnum,
 	return 0;
 }
 
+/**
+ * cros_read_buf() - Read information into a buf and parse it
+ *
+ * @bflow: Bootflow to update
+ * @buf: Buffer to use
+ * @size: Size of buffer and number of bytes to read thereinto
+ * @start: Start offset to read from on disk
+ * @before_base: Number of bytes to read before the bootloader base
+ * @uuid: UUID string if supported, else NULL
+ * Return: 0 if OK, -ENOMEM if out of memory, -EIO on read failure
+ */
+static int cros_read_buf(struct bootflow *bflow, void *buf, ulong size,
+			 loff_t start, ulong before_base, const char *uuid)
+{
+	struct blk_desc *desc = dev_get_uclass_plat(bflow->blk);
+	ulong base, setup, cmdline, kern_base;
+	ulong num_blks;
+	int ret;
+
+	num_blks = size >> desc->log2blksz;
+	log_debug("Reading info to %lx, blk=%s, size=%lx, blocks=%lx\n",
+		  (ulong)map_to_sysmem(buf), bflow->blk->name, size, num_blks);
+	ret = blk_read(bflow->blk, start, num_blks, buf);
+	if (ret != num_blks)
+		return log_msg_ret("inf", -EIO);
+	base = map_to_sysmem(buf) + before_base;
+
+	setup = base + X86_SETUP_OFFSET;
+	cmdline = base + CMDLINE_OFFSET;
+	kern_base = base + X86_KERNEL_OFFSET;
+	log_debug("base %lx setup %lx cmdline %lx kern_base %lx\n", base,
+		  setup, cmdline, kern_base);
+
+#ifdef CONFIG_X86
+	const char *version;
+
+	version = zimage_get_kernel_version(map_sysmem(setup, 0),
+					    map_sysmem(kern_base, 0));
+	log_debug("version %s\n", version);
+	if (version)
+		bflow->name = strdup(version);
+#endif
+	if (!bflow->name)
+		bflow->name = strdup("ChromeOS");
+	if (!bflow->name)
+		return log_msg_ret("nam", -ENOMEM);
+	bflow->os_name = strdup("ChromeOS");
+	if (!bflow->os_name)
+		return log_msg_ret("os", -ENOMEM);
+
+	ret = copy_cmdline(map_sysmem(cmdline, 0), uuid, &bflow->cmdline);
+	if (ret)
+		return log_msg_ret("cmd", ret);
+	bflow->x86_setup = map_sysmem(setup, 0);
+
+	return 0;
+}
+
+/**
+ * cros_read_info() - Read information and fill out the bootflow
+ *
+ * @bflow: Bootflow to update
+ * @uuid: UUID string if supported, else NULL
+ * @preamble: Kernel preamble information
+ * Return: 0 if OK, -ENOMEM if out of memory, -EIO on read failure
+ */
+static int cros_read_info(struct bootflow *bflow, const char *uuid,
+			  const struct vb2_kernel_preamble *preamble)
+{
+	struct cros_priv *priv = bflow->bootmeth_priv;
+	struct udevice *blk = bflow->blk;
+	struct blk_desc *desc = dev_get_uclass_plat(blk);
+	ulong offset, size, before_base;
+	void *buf;
+	int ret;
+
+	log_debug("Kernel preamble at %lx, version major %x, minor %x\n",
+		  (ulong)map_to_sysmem(preamble),
+		  preamble->header_version_major,
+		  preamble->header_version_minor);
+
+	log_debug("  - load_address %lx, bl_addr %lx, bl_size %lx\n",
+		  (ulong)preamble->body_load_address,
+		  (ulong)preamble->bootloader_address,
+		  (ulong)preamble->bootloader_size);
+
+	priv->body_size = preamble->body_signature.data_size;
+	priv->body_load_address = preamble->body_load_address;
+	priv->bootloader_address = preamble->bootloader_address;
+	priv->bootloader_size = preamble->bootloader_size;
+	log_debug("Kernel body at %lx size %lx\n", priv->body_offset,
+		  priv->body_size);
+
+	/* Work out how many bytes to read before the bootloader base */
+	before_base = -CMDLINE_OFFSET;
+
+	/* Read the cmdline through to the end of the bootloader */
+	size = priv->bootloader_size + before_base;
+	offset = priv->body_offset +
+		(priv->bootloader_address - priv->body_load_address) +
+		CMDLINE_OFFSET;
+	buf = malloc(size);
+	if (!buf)
+		return log_msg_ret("buf", -ENOMEM);
+
+	ret = cros_read_buf(bflow, buf, size,
+			    priv->part_start + (offset >> desc->log2blksz),
+			    before_base, uuid);
+	if (ret) {
+		/* Clear this since the buffer is invalid */
+		bflow->x86_setup = NULL;
+		free(buf);
+		return log_msg_ret("pro", ret);
+	}
+	priv->info_buf = buf;
+
+	return 0;
+}
+
 static int cros_read_bootflow(struct udevice *dev, struct bootflow *bflow)
 {
 	struct blk_desc *desc = dev_get_uclass_plat(bflow->blk);
-- 
2.41.0.487.g6d72f3e995-goog