From d2e94f417f7f5fcd227f44ccea88e00cf6dd2d8d Mon Sep 17 00:00:00 2001 From: Doug Anderson Date: Thu, 2 Feb 2012 22:58:28 -0800 Subject: of: Support CONFIG_CMDLINE_EXTEND config option The old logic assumes CMDLINE_FROM_BOOTLOADER vs. CMDLINE_FORCE and ignores CMDLINE_EXTEND. Here's the old logic: - CONFIG_CMDLINE_FORCE=true CONFIG_CMDLINE - dt bootargs=non-empty: dt bootargs - dt bootargs=empty, @data is non-empty string @data is left unchanged - dt bootargs=empty, @data is empty string CONFIG_CMDLINE (or "" if that's not defined) The new logic is now documented in of_fdt.h and is copied here for reference: - CONFIG_CMDLINE_FORCE=true CONFIG_CMDLINE - CONFIG_CMDLINE_EXTEND=true, @data is non-empty string @data + dt bootargs (even if dt bootargs are empty) - CONFIG_CMDLINE_EXTEND=true, @data is empty string CONFIG_CMDLINE + dt bootargs (even if dt bootargs are empty) - CMDLINE_FROM_BOOTLOADER=true, dt bootargs=non-empty: dt bootargs - CMDLINE_FROM_BOOTLOADER=true, dt bootargs=empty, @data is non-empty string @data is left unchanged - CMDLINE_FROM_BOOTLOADER=true, dt bootargs=empty, @data is empty string CONFIG_CMDLINE (or "" if that's not defined) Signed-off-by: Doug Anderson CC: devicetree-discuss@lists.ozlabs.org CC: Grant Likely CC: Benjamin Herrenschmidt CC: Rob Herring Change-Id: I40ace250847f813358125dfcaa8998fd32cf7ea3 Signed-off-by: Colin Cross --- include/linux/of_fdt.h | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) (limited to 'include/linux') diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h index df9ef3801812..fbbb89b69012 100644 --- a/include/linux/of_fdt.h +++ b/include/linux/of_fdt.h @@ -59,6 +59,27 @@ extern int of_flat_dt_match(unsigned long node, const char *const *matches); extern unsigned long of_get_flat_dt_root(void); extern int of_get_flat_dt_size(void); +/* + * early_init_dt_scan_chosen - scan the device tree for ramdisk and bootargs + * + * The boot arguments will be placed into the memory pointed to by @data. + * That memory should be COMMAND_LINE_SIZE big and initialized to be a valid + * (possibly empty) string. Logic for what will be in @data after this + * function finishes: + * + * - CONFIG_CMDLINE_FORCE=true + * CONFIG_CMDLINE + * - CONFIG_CMDLINE_EXTEND=true, @data is non-empty string + * @data + dt bootargs (even if dt bootargs are empty) + * - CONFIG_CMDLINE_EXTEND=true, @data is empty string + * CONFIG_CMDLINE + dt bootargs (even if dt bootargs are empty) + * - CMDLINE_FROM_BOOTLOADER=true, dt bootargs=non-empty: + * dt bootargs + * - CMDLINE_FROM_BOOTLOADER=true, dt bootargs=empty, @data is non-empty string + * @data is left unchanged + * - CMDLINE_FROM_BOOTLOADER=true, dt bootargs=empty, @data is empty string + * CONFIG_CMDLINE (or "" if that's not defined) + */ extern int early_init_dt_scan_chosen(unsigned long node, const char *uname, int depth, void *data); extern int early_init_dt_scan_memory(unsigned long node, const char *uname, -- cgit v1.2.3