octeon: Ignore MEM boot param when too small

Cisco RV0XX u-boot sets MEM=2048 as boot param. We assume that at least
4MB (mem_alloc_size) of ram is needed to run linux on cavium boards, so
if mem < 4M - ignore it and set default value

Signed-off-by: Michał Osowiecki <michal.osowiecki@gmail.com>

target/linux/octeon/patches-4.4/170-cisco-hack.patch

@@ -0,0 +1,31 @@
+From patchwork Wed Jun  8 13:49:26 2016
+Content-Type: text/plain; charset="utf-8"
+MIME-Version: 1.0
+Content-Transfer-Encoding: 8bit
+Subject: [LEDE-DEV] cavium: Ignore MEM boot param when too small
+From: =?utf-8?q?Micha=C5=82_Osowiecki?= <michal.osowiecki@gmail.com>
+X-Patchwork-Id: 632273
+Message-Id: <57582266.8020105@gmail.com>
+To: lede-dev@lists.infradead.org
+Date: Wed, 8 Jun 2016 15:49:26 +0200
+
+Cisco RV0XX u-boot sets MEM=2048 as boot param. We assume that at least 
+4MB (mem_alloc_size) of ram is needed to run linux on cavium boards, so 
+if mem < 4M - ignore it and set default value
+
+
+Signed-off-by: Michał Osowiecki <michal.osowiecki@gmail.com>
+
+--- a/arch/mips/cavium-octeon/setup.c
++++ b/arch/mips/cavium-octeon/setup.c
+@@ -944,6 +944,10 @@
+ 	if (mem_alloc_size > MAX_MEMORY)
+ 		mem_alloc_size = MAX_MEMORY;
+ 
++	/* Ignore bootarg MEM <= 4MB - cisco uses a b0rked uboot env on their products */
++	if (MAX_MEMORY <= mem_alloc_size)
++		MAX_MEMORY = 512ull << 20;
++
+ /* Crashkernel ignores bootmem list. It relies on mem=X@Y option */
+ #ifdef CONFIG_CRASH_DUMP
+ 	add_memory_region(RESERVE_LOW_MEM, MAX_MEMORY, BOOT_MEM_RAM);