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Commit d2e94f41 authored by Doug Anderson's avatar Doug Anderson Committed by John Stultz
Browse files

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: default avatarDoug Anderson <dianders@chromium.org>
CC: devicetree-discuss@lists.ozlabs.org
CC: Grant Likely <grant.likely@secretlab.ca>
CC: Benjamin Herrenschmidt <benh@kernel.crashing.org>
CC: Rob Herring <rob.herring@calxeda.com>
Change-Id: I40ace250847f813358125dfcaa8998fd32cf7ea3
Signed-off-by: default avatarColin Cross <ccross@android.com>
parent 5813f5de

drivers/of/fdt.c

+40 −16
Original line number Diff line number Diff line
@@ -938,6 +938,29 @@ int __init early_init_dt_scan_memory(unsigned long node, const char *uname, 
	return 0;

}



/*

 * Convert configs to something easy to use in C code

 */

#if defined(CONFIG_CMDLINE_FORCE)

static const int overwrite_incoming_cmdline = 1;

static const int read_dt_cmdline;

static const int concat_cmdline;

#elif defined(CONFIG_CMDLINE_EXTEND)

static const int overwrite_incoming_cmdline;

static const int read_dt_cmdline = 1;

static const int concat_cmdline = 1;

#else /* CMDLINE_FROM_BOOTLOADER */

static const int overwrite_incoming_cmdline;

static const int read_dt_cmdline = 1;

static const int concat_cmdline;

#endif



#ifdef CONFIG_CMDLINE

static const char *config_cmdline = CONFIG_CMDLINE;

#else

static const char *config_cmdline = "";

#endif



int __init early_init_dt_scan_chosen(unsigned long node, const char *uname,

				     int depth, void *data)

{
@@ -952,22 +975,23 @@ int __init early_init_dt_scan_chosen(unsigned long node, const char *uname, 


	early_init_dt_check_for_initrd(node);



	/* Retrieve command line */

	p = of_get_flat_dt_prop(node, "bootargs", &l);

	if (p != NULL && l > 0)

		strlcpy(data, p, min((int)l, COMMAND_LINE_SIZE));

	/* Put CONFIG_CMDLINE in if forced or if data had nothing in it to start */

	if (overwrite_incoming_cmdline || !((char *)data)[0])

		strlcpy(data, config_cmdline, COMMAND_LINE_SIZE);



	/*

	 * CONFIG_CMDLINE is meant to be a default in case nothing else

	 * managed to set the command line, unless CONFIG_CMDLINE_FORCE

	 * is set in which case we override whatever was found earlier.

	 */

#ifdef CONFIG_CMDLINE

#ifndef CONFIG_CMDLINE_FORCE

	if (!((char *)data)[0])

#endif

		strlcpy(data, CONFIG_CMDLINE, COMMAND_LINE_SIZE);

#endif /* CONFIG_CMDLINE */

	/* Retrieve command line unless forcing */

	if (read_dt_cmdline) {

		p = of_get_flat_dt_prop(node, "bootargs", &l);

		if (p != NULL && l > 0) {

			if (concat_cmdline) {

				strlcat(data, " ", COMMAND_LINE_SIZE);

				strlcat(data, p, min_t(int, (int)l,

						       COMMAND_LINE_SIZE));

			} else

				strlcpy(data, p, min_t(int, (int)l,

						       COMMAND_LINE_SIZE));

		}

	}



	pr_debug("Command line is: %s\n", (char*)data);

include/linux/of_fdt.h

+21 −0
Original line number Diff line number Diff line
@@ -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,