From: Sven Eckelmann <sven@narfation.org>
Date: Mon, 23 Nov 2020 16:57:31 +0100
Subject: ath79: Fix fallback to bootloader cmdline on empty DT bootargs
The MIPS code is supposed to fall back to u-boots bootargs whenever the
/chosen/bootargs property is missing. But this feature was accidentally
disabled when the boot_command_line was initialized with an empty space
just to work around problems with early_init_dt_scan_chosen.
But this feature is necessary for some boards which have a dualboot
mechanism and whose u-boot is calculating the correct partition at runtime
without writing this information back to the u-boot-env.
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Origin: backport, https://github.com/openwrt/openwrt/commit/727eebbad1b9dea91174ea675cb64ea13484f790
diff --git a/target/linux/ath79/patches-4.14/0038-MIPS-Setup-boot_command_line-before-plat_mem_setup.patch b/target/linux/ath79/patches-4.14/0038-MIPS-Setup-boot_command_line-before-plat_mem_setup.patch
new file mode 100644
index 0000000000000000000000000000000000000000..90d2ca7a0cb16d3f1e71779bfa551f498fd59755
--- /dev/null
+++ b/target/linux/ath79/patches-4.14/0038-MIPS-Setup-boot_command_line-before-plat_mem_setup.patch
@@ -0,0 +1,82 @@
+From: Paul Burton <paul.burton@mips.com>
+Date: Tue, 16 Jan 2018 16:47:57 +0100
+Subject: MIPS: Setup boot_command_line before plat_mem_setup
+
+Platforms using DT will typically call __dt_setup_arch from
+plat_mem_setup. This in turn calls early_init_dt_scan. When
+CONFIG_CMDLINE is set, this leads to its value being copied into
+boot_command_line by early_init_dt_scan_chosen. If this happens before
+the code setting up boot_command_line in arch_mem_init runs, that code
+will go on to append CONFIG_CMDLINE (via builtin_cmdline) to
+boot_command_line again, duplicating it. For some command line
+parameters (eg. earlycon) this can be a problem. Set up
+boot_command_line before early_init_dt_scan_chosen gets called such that
+it will not write CONFIG_CMDLINE in this scenario & the arguments aren't
+duplicated.
+
+Origin: upstream, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=8ce355cf2e38afdb364d03d12b23d9cf44c3b7f1
+Signed-off-by: Paul Burton <paul.burton@mips.com>
+Acked-by: Mathieu Malaterre <malat@debian.org>
+Cc: Ralf Baechle <ralf@linux-mips.org>
+Cc: Maarten ter Huurne <maarten@treewalker.org>
+Cc: linux-mips@linux-mips.org
+Patchwork: https://patchwork.linux-mips.org/patch/18483/
+Signed-off-by: James Hogan <jhogan@kernel.org>
+
+diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
+index abd7ee9e90ab0dd0d01d970c84d90a2c4edf609b..c0f51fd4e0b3970e4f019094091578504e2f56eb 100644
+--- a/arch/mips/kernel/setup.c
++++ b/arch/mips/kernel/setup.c
+@@ -833,25 +833,6 @@ static void __init arch_mem_init(char **cmdline_p)
+ struct memblock_region *reg;
+ extern void plat_mem_setup(void);
+
+- /* call board setup routine */
+- plat_mem_setup();
+-
+- /*
+- * Make sure all kernel memory is in the maps. The "UP" and
+- * "DOWN" are opposite for initdata since if it crosses over
+- * into another memory section you don't want that to be
+- * freed when the initdata is freed.
+- */
+- arch_mem_addpart(PFN_DOWN(__pa_symbol(&_text)) << PAGE_SHIFT,
+- PFN_UP(__pa_symbol(&_edata)) << PAGE_SHIFT,
+- BOOT_MEM_RAM);
+- arch_mem_addpart(PFN_UP(__pa_symbol(&__init_begin)) << PAGE_SHIFT,
+- PFN_DOWN(__pa_symbol(&__init_end)) << PAGE_SHIFT,
+- BOOT_MEM_INIT_RAM);
+-
+- pr_info("Determined physical RAM map:\n");
+- print_memory_map();
+-
+ #if defined(CONFIG_CMDLINE_BOOL) && defined(CONFIG_CMDLINE_OVERRIDE)
+ strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+ #else
+@@ -879,6 +860,26 @@ static void __init arch_mem_init(char **cmdline_p)
+ }
+ #endif
+ #endif
++
++ /* call board setup routine */
++ plat_mem_setup();
++
++ /*
++ * Make sure all kernel memory is in the maps. The "UP" and
++ * "DOWN" are opposite for initdata since if it crosses over
++ * into another memory section you don't want that to be
++ * freed when the initdata is freed.
++ */
++ arch_mem_addpart(PFN_DOWN(__pa_symbol(&_text)) << PAGE_SHIFT,
++ PFN_UP(__pa_symbol(&_edata)) << PAGE_SHIFT,
++ BOOT_MEM_RAM);
++ arch_mem_addpart(PFN_UP(__pa_symbol(&__init_begin)) << PAGE_SHIFT,
++ PFN_DOWN(__pa_symbol(&__init_end)) << PAGE_SHIFT,
++ BOOT_MEM_INIT_RAM);
++
++ pr_info("Determined physical RAM map:\n");
++ print_memory_map();
++
+ strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
+
+ *cmdline_p = command_line;
diff --git a/target/linux/ath79/patches-4.14/0039-MIPS-Fix-CONFIG_CMDLINE-handling.patch b/target/linux/ath79/patches-4.14/0039-MIPS-Fix-CONFIG_CMDLINE-handling.patch
new file mode 100644
index 0000000000000000000000000000000000000000..ab040c459454b1670b08afa2082e06637280da52
--- /dev/null
+++ b/target/linux/ath79/patches-4.14/0039-MIPS-Fix-CONFIG_CMDLINE-handling.patch
@@ -0,0 +1,119 @@
+From: Paul Burton <paul.burton@mips.com>
+Date: Thu, 27 Sep 2018 22:59:18 +0000
+Subject: MIPS: Fix CONFIG_CMDLINE handling
+
+Commit 8ce355cf2e38 ("MIPS: Setup boot_command_line before
+plat_mem_setup") fixed a problem for systems which have
+CONFIG_CMDLINE_BOOL=y & use a DT with a chosen node that has either no
+bootargs property or an empty one. In this configuration
+early_init_dt_scan_chosen() copies CONFIG_CMDLINE into
+boot_command_line, but the MIPS code doesn't know this so it appends
+CONFIG_CMDLINE (via builtin_cmdline) to boot_command_line again. The
+result is that boot_command_line contains the arguments from
+CONFIG_CMDLINE twice.
+
+That commit took the approach of simply setting up boot_command_line
+from the MIPS code before early_init_dt_scan_chosen() runs, causing it
+not to copy CONFIG_CMDLINE to boot_command_line if a chosen node with no
+bootargs property is found.
+
+Unfortunately this is problematic for systems which do have a non-empty
+bootargs property & CONFIG_CMDLINE_BOOL=y. There
+early_init_dt_scan_chosen() will overwrite boot_command_line with the
+arguments from DT, which means we lose those from CONFIG_CMDLINE
+entirely. This breaks CONFIG_MIPS_CMDLINE_DTB_EXTEND. If we have
+CONFIG_MIPS_CMDLINE_FROM_BOOTLOADER or
+CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND selected and the DT has a bootargs
+property which we should ignore, it will instead be honoured breaking
+those configurations too.
+
+Fix this by reverting commit 8ce355cf2e38 ("MIPS: Setup
+boot_command_line before plat_mem_setup") to restore the former
+behaviour, and fixing the CONFIG_CMDLINE duplication issue by
+initializing boot_command_line to a non-empty string that
+early_init_dt_scan_chosen() will not overwrite with CONFIG_CMDLINE.
+
+This is a little ugly, but cleanup in this area is on its way. In the
+meantime this is at least easy to backport & contains the ugliness
+within arch/mips/.
+
+Origin: upstream, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=951d223c6c16ed5d2a71a4d1f13c1e65d6882156
+Signed-off-by: Paul Burton <paul.burton@mips.com>
+Fixes: 8ce355cf2e38 ("MIPS: Setup boot_command_line before plat_mem_setup")
+References: https://patchwork.linux-mips.org/patch/18804/
+Patchwork: https://patchwork.linux-mips.org/patch/20813/
+Cc: Frank Rowand <frowand.list@gmail.com>
+Cc: Jaedon Shin <jaedon.shin@gmail.com>
+Cc: Mathieu Malaterre <malat@debian.org>
+Cc: Rob Herring <robh+dt@kernel.org>
+Cc: devicetree@vger.kernel.org
+Cc: linux-kernel@vger.kernel.org
+Cc: linux-mips@linux-mips.org
+Cc: stable@vger.kernel.org # v4.16+
+
+diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
+index c0f51fd4e0b3970e4f019094091578504e2f56eb..71070ec8da136495d2efed0aa79dff44149d565f 100644
+--- a/arch/mips/kernel/setup.c
++++ b/arch/mips/kernel/setup.c
+@@ -833,6 +833,34 @@ static void __init arch_mem_init(char **cmdline_p)
+ struct memblock_region *reg;
+ extern void plat_mem_setup(void);
+
++ /*
++ * Initialize boot_command_line to an innocuous but non-empty string in
++ * order to prevent early_init_dt_scan_chosen() from copying
++ * CONFIG_CMDLINE into it without our knowledge. We handle
++ * CONFIG_CMDLINE ourselves below & don't want to duplicate its
++ * content because repeating arguments can be problematic.
++ */
++ strlcpy(boot_command_line, " ", COMMAND_LINE_SIZE);
++
++ /* call board setup routine */
++ plat_mem_setup();
++
++ /*
++ * Make sure all kernel memory is in the maps. The "UP" and
++ * "DOWN" are opposite for initdata since if it crosses over
++ * into another memory section you don't want that to be
++ * freed when the initdata is freed.
++ */
++ arch_mem_addpart(PFN_DOWN(__pa_symbol(&_text)) << PAGE_SHIFT,
++ PFN_UP(__pa_symbol(&_edata)) << PAGE_SHIFT,
++ BOOT_MEM_RAM);
++ arch_mem_addpart(PFN_UP(__pa_symbol(&__init_begin)) << PAGE_SHIFT,
++ PFN_DOWN(__pa_symbol(&__init_end)) << PAGE_SHIFT,
++ BOOT_MEM_INIT_RAM);
++
++ pr_info("Determined physical RAM map:\n");
++ print_memory_map();
++
+ #if defined(CONFIG_CMDLINE_BOOL) && defined(CONFIG_CMDLINE_OVERRIDE)
+ strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+ #else
+@@ -860,26 +888,6 @@ static void __init arch_mem_init(char **cmdline_p)
+ }
+ #endif
+ #endif
+-
+- /* call board setup routine */
+- plat_mem_setup();
+-
+- /*
+- * Make sure all kernel memory is in the maps. The "UP" and
+- * "DOWN" are opposite for initdata since if it crosses over
+- * into another memory section you don't want that to be
+- * freed when the initdata is freed.
+- */
+- arch_mem_addpart(PFN_DOWN(__pa_symbol(&_text)) << PAGE_SHIFT,
+- PFN_UP(__pa_symbol(&_edata)) << PAGE_SHIFT,
+- BOOT_MEM_RAM);
+- arch_mem_addpart(PFN_UP(__pa_symbol(&__init_begin)) << PAGE_SHIFT,
+- PFN_DOWN(__pa_symbol(&__init_end)) << PAGE_SHIFT,
+- BOOT_MEM_INIT_RAM);
+-
+- pr_info("Determined physical RAM map:\n");
+- print_memory_map();
+-
+ strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
+
+ *cmdline_p = command_line;
diff --git a/target/linux/ath79/patches-4.14/0040-MIPS-cmdline-Clean-up-boot_command_line-initializati.patch b/target/linux/ath79/patches-4.14/0040-MIPS-cmdline-Clean-up-boot_command_line-initializati.patch
new file mode 100644
index 0000000000000000000000000000000000000000..2cba97d5e85bb863ca95c0715110b69e4964ea51
--- /dev/null
+++ b/target/linux/ath79/patches-4.14/0040-MIPS-cmdline-Clean-up-boot_command_line-initializati.patch
@@ -0,0 +1,196 @@
+From: Paul Burton <paul.burton@mips.com>
+Date: Wed, 9 Oct 2019 23:09:45 +0000
+Subject: MIPS: cmdline: Clean up boot_command_line initialization
+
+Our current code to initialize boot_command_line is a mess. Some of this
+is due to the addition of too many options over the years, and some of
+this is due to workarounds for early_init_dt_scan_chosen() performing
+actions specific to options from other architectures that probably
+shouldn't be in generic code.
+
+Clean this up by introducing a new bootcmdline_init() function that
+simplifies the initialization somewhat. The major changes are:
+
+- Because bootcmdline_init() is a function it can return early in the
+ CONFIG_CMDLINE_OVERRIDE case.
+
+- We clear boot_command_line rather than inheriting whatever
+ early_init_dt_scan_chosen() may have left us. This means we no longer
+ need to set boot_command_line to a space character in an attempt to
+ prevent early_init_dt_scan_chosen() from copying CONFIG_CMDLINE into
+ boot_command_line without us knowing about it.
+
+- Indirection via USE_PROM_CMDLINE, USE_DTB_CMDLINE, EXTEND_WITH_PROM &
+ BUILTIN_EXTEND_WITH_PROM macros is removed; they seemingly served only
+ to obfuscate the code.
+
+- The logic is cleaner, clearer & commented.
+
+Two minor drawbacks of this approach are:
+
+1) We call of_scan_flat_dt(), which means we scan through the DT again.
+ The overhead is fairly minimal & shouldn't be noticeable.
+
+2) cmdline_scan_chosen() duplicates a small amount of the logic from
+ early_init_dt_scan_chosen(). Alternatives might be to allow the
+ generic FDT code to keep & expose a copy of the arguments taken from
+ the /chosen node's bootargs property, or to introduce a function like
+ early_init_dt_scan_chosen() that retrieves them without modification
+ to handle CONFIG_CMDLINE. Neither of these sounds particularly
+ cleaner though, and this way we at least keep the extra work in
+ arch/mips.
+
+Origin: backport, https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7784cac697351f0cc0a4bb619594c0c99348c5aa
+Signed-off-by: Paul Burton <paul.burton@mips.com>
+Cc: linux-mips@vger.kernel.org
+
+diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
+index 71070ec8da136495d2efed0aa79dff44149d565f..c2b659a2e2ce0f2074f4fc13cd24283d66ac5594 100644
+--- a/arch/mips/kernel/setup.c
++++ b/arch/mips/kernel/setup.c
+@@ -822,26 +822,94 @@ static void __init request_crashkernel(struct resource *res)
+ }
+ #endif /* !defined(CONFIG_KEXEC) */
+
+-#define USE_PROM_CMDLINE IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_BOOTLOADER)
+-#define USE_DTB_CMDLINE IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_DTB)
+-#define EXTEND_WITH_PROM IS_ENABLED(CONFIG_MIPS_CMDLINE_DTB_EXTEND)
+-#define BUILTIN_EXTEND_WITH_PROM \
+- IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND)
++static void __init bootcmdline_append(const char *s, size_t max)
++{
++ if (!s[0] || !max)
++ return;
++
++ if (boot_command_line[0])
++ strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
++
++ strlcat(boot_command_line, s, max);
++}
++
++static int __init bootcmdline_scan_chosen(unsigned long node, const char *uname,
++ int depth, void *data)
++{
++ bool *dt_bootargs = data;
++ const char *p;
++ int l;
++
++ if (depth != 1 || !data ||
++ (strcmp(uname, "chosen") != 0 && strcmp(uname, "chosen@0") != 0))
++ return 0;
++
++ p = of_get_flat_dt_prop(node, "bootargs", &l);
++ if (p != NULL && l > 0) {
++ bootcmdline_append(p, min(l, COMMAND_LINE_SIZE));
++ *dt_bootargs = true;
++ }
++
++ return 1;
++}
++
++static void __init bootcmdline_init(char **cmdline_p)
++{
++ bool dt_bootargs = false;
++
++ /*
++ * If CMDLINE_OVERRIDE is enabled then initializing the command line is
++ * trivial - we simply use the built-in command line unconditionally &
++ * unmodified.
++ */
++ if (IS_ENABLED(CONFIG_CMDLINE_OVERRIDE)) {
++ strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
++ return;
++ }
++
++ /*
++ * If the user specified a built-in command line &
++ * MIPS_CMDLINE_BUILTIN_EXTEND, then the built-in command line is
++ * prepended to arguments from the bootloader or DT so we'll copy them
++ * to the start of boot_command_line here. Otherwise, empty
++ * boot_command_line to undo anything early_init_dt_scan_chosen() did.
++ */
++ if (IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND))
++ strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
++ else
++ boot_command_line[0] = 0;
++
++ /*
++ * If we're configured to take boot arguments from DT, look for those
++ * now.
++ */
++ if (IS_ENABLED(CONFIG_MIPS_CMDLINE_FROM_DTB))
++ of_scan_flat_dt(bootcmdline_scan_chosen, &dt_bootargs);
++
++ /*
++ * If we didn't get any arguments from DT (regardless of whether that's
++ * because we weren't configured to look for them, or because we looked
++ * & found none) then we'll take arguments from the bootloader.
++ * plat_mem_setup() should have filled arcs_cmdline with arguments from
++ * the bootloader.
++ */
++ if (IS_ENABLED(CONFIG_MIPS_CMDLINE_DTB_EXTEND) || !dt_bootargs)
++ bootcmdline_append(arcs_cmdline, COMMAND_LINE_SIZE);
++
++ /*
++ * If the user specified a built-in command line & we didn't already
++ * prepend it, we append it to boot_command_line here.
++ */
++ if (IS_ENABLED(CONFIG_CMDLINE_BOOL) &&
++ !IS_ENABLED(CONFIG_MIPS_CMDLINE_BUILTIN_EXTEND))
++ bootcmdline_append(builtin_cmdline, COMMAND_LINE_SIZE);
++}
+
+ static void __init arch_mem_init(char **cmdline_p)
+ {
+ struct memblock_region *reg;
+ extern void plat_mem_setup(void);
+
+- /*
+- * Initialize boot_command_line to an innocuous but non-empty string in
+- * order to prevent early_init_dt_scan_chosen() from copying
+- * CONFIG_CMDLINE into it without our knowledge. We handle
+- * CONFIG_CMDLINE ourselves below & don't want to duplicate its
+- * content because repeating arguments can be problematic.
+- */
+- strlcpy(boot_command_line, " ", COMMAND_LINE_SIZE);
+-
+ /* call board setup routine */
+ plat_mem_setup();
+
+@@ -861,35 +929,8 @@ static void __init arch_mem_init(char **cmdline_p)
+ pr_info("Determined physical RAM map:\n");
+ print_memory_map();
+
+-#if defined(CONFIG_CMDLINE_BOOL) && defined(CONFIG_CMDLINE_OVERRIDE)
+- strlcpy(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+-#else
+- if ((USE_PROM_CMDLINE && arcs_cmdline[0]) ||
+- (USE_DTB_CMDLINE && !boot_command_line[0]))
+- strlcpy(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE);
+-
+- if (EXTEND_WITH_PROM && arcs_cmdline[0]) {
+- if (boot_command_line[0])
+- strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
+- strlcat(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE);
+- }
+-
+-#if defined(CONFIG_CMDLINE_BOOL)
+- if (builtin_cmdline[0]) {
+- if (boot_command_line[0])
+- strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
+- strlcat(boot_command_line, builtin_cmdline, COMMAND_LINE_SIZE);
+- }
+-
+- if (BUILTIN_EXTEND_WITH_PROM && arcs_cmdline[0]) {
+- if (boot_command_line[0])
+- strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
+- strlcat(boot_command_line, arcs_cmdline, COMMAND_LINE_SIZE);
+- }
+-#endif
+-#endif
++ bootcmdline_init(cmdline_p);
+ strlcpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
+-
+ *cmdline_p = command_line;
+
+ parse_early_param();