Commit 59ed9413 authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: [cmdline] uboot cmdline handling rework 



* Moved cmdline copy from asm to "C" - allows for more robust checking
  of pointer validity etc.

* Remove the Kconfig option to do so, base it on a runtime value passed
  by u-boot

Signed-off-by: default avatarVineet Gupta <vgupta@synopsys.com>
parent d8e8c7dd

arch/arc/Kconfig

+0 −11
Original line number Diff line number Diff line
@@ -409,17 +409,6 @@ config ARC_DBG_TLB_MISS_COUNT 
	  Counts number of I and D TLB Misses and exports them via Debugfs

	  The counters can be cleared via Debugfs as well



config CMDLINE_UBOOT

	bool "Support U-boot kernel command line passing"

	default n

	help

	  If you are using U-boot (www.denx.de) and wish to pass the kernel

	  command line from the U-boot environment to the Linux kernel then

	  switch this option on.

	  ARC U-boot will setup the cmdline in RAM/flash and set r2 to point

	  to it. kernel startup code will append this to DeviceTree

	  /bootargs provided cmdline args.



config ARC_BUILTIN_DTB_NAME

	string "Built in DTB"

	help

arch/arc/kernel/head.S

+7 −19
Original line number Diff line number Diff line
@@ -49,25 +49,13 @@ stext: 
	st.ab   0, [r5,4]

	brlt    r5, r6, 1b



#ifdef CONFIG_CMDLINE_UBOOT

	; support for bootloader provided cmdline

	;    If cmdline passed by u-boot, then

	;    r0 = 1  (because ATAGS parsing, now retired, used to use 0)

	;    r1 = magic number (board identity)

	;    r2 = addr of cmdline string (somewhere in memory/flash)



	brne	r0, 1, .Lother_bootup_chores	; u-boot didn't pass cmdline

	breq	r2, 0, .Lother_bootup_chores	; or cmdline is NULL



	mov	r5, @command_line

1:

	ldb.ab  r6, [r2, 1]

	breq    r6, 0, .Lother_bootup_chores

	b.d     1b

	stb.ab  r6, [r5, 1]

#endif



.Lother_bootup_chores:

	; Uboot - kernel ABI

	;    r0 = [0] No uboot interaction, [1] cmdline in r2, [2] DTB in r2

	;    r1 = magic number (board identity, unused as of now

	;    r2 = pointer to uboot provided cmdline or external DTB in mem

	; These are handled later in setup_arch()

	st	r0, [@uboot_tag]

	st	r2, [@uboot_arg]



	; Identify if running on ISS vs Silicon

	; 	IDENTITY Reg [ 3  2  1  0 ]

arch/arc/kernel/setup.c

+27 −12
Original line number Diff line number Diff line
@@ -29,7 +29,10 @@ 


int running_on_hw = 1;	/* vs. on ISS */



char __initdata command_line[COMMAND_LINE_SIZE];

/* Part of U-boot ABI: see head.S */

int __initdata uboot_tag;

char __initdata *uboot_arg;



const struct machine_desc *machine_desc;



struct task_struct *_current_task[NR_CPUS];	/* For stack switching */
@@ -311,19 +314,31 @@ void setup_processor(void) 
	arc_chk_fpu();

}



static inline int is_kernel(unsigned long addr)

{

	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)

		return 1;

	return 0;

}



void __init setup_arch(char **cmdline_p)

{

	/* This also populates @boot_command_line from /bootargs */

		machine_desc = setup_machine_fdt(__dtb_start);

		if (!machine_desc)

			panic("Embedded DT invalid\n");



	/* Append any u-boot provided cmdline */

#ifdef CONFIG_CMDLINE_UBOOT

	/* Add a whitespace seperator between the 2 cmdlines */

		/*

		 * Append uboot cmdline to embedded DT cmdline.

		 * setup_machine_fdt() would have populated @boot_command_line

		 */

		if (uboot_tag == 1) {

			BUG_ON(is_kernel(unsigned long)uboot_arg);



			/* Ensure a whitespace between the 2 cmdlines */

			strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);

	strlcat(boot_command_line, command_line, COMMAND_LINE_SIZE);

#endif

			strlcat(boot_command_line, uboot_arg,

				COMMAND_LINE_SIZE);

		}



	/* Save unparsed command line copy for /proc/cmdline */

	*cmdline_p = boot_command_line;