[Feature]add MT2731_MP2_MR2_SVN388 baseline version
Change-Id: Ief04314834b31e27effab435d3ca8ba33b499059
diff --git a/src/kernel/linux/v4.14/arch/arm/mm/proc-feroceon.S b/src/kernel/linux/v4.14/arch/arm/mm/proc-feroceon.S
new file mode 100644
index 0000000..92e08bf
--- /dev/null
+++ b/src/kernel/linux/v4.14/arch/arm/mm/proc-feroceon.S
@@ -0,0 +1,626 @@
+/*
+ * linux/arch/arm/mm/proc-feroceon.S: MMU functions for Feroceon
+ *
+ * Heavily based on proc-arm926.S
+ * Maintainer: Assaf Hoffman <hoffman@marvell.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/assembler.h>
+#include <asm/hwcap.h>
+#include <asm/pgtable-hwdef.h>
+#include <asm/pgtable.h>
+#include <asm/page.h>
+#include <asm/ptrace.h>
+#include "proc-macros.S"
+
+/*
+ * This is the maximum size of an area which will be invalidated
+ * using the single invalidate entry instructions. Anything larger
+ * than this, and we go for the whole cache.
+ *
+ * This value should be chosen such that we choose the cheapest
+ * alternative.
+ */
+#define CACHE_DLIMIT 16384
+
+/*
+ * the cache line size of the I and D cache
+ */
+#define CACHE_DLINESIZE 32
+
+ .bss
+ .align 3
+__cache_params_loc:
+ .space 8
+
+ .text
+__cache_params:
+ .word __cache_params_loc
+
+/*
+ * cpu_feroceon_proc_init()
+ */
+ENTRY(cpu_feroceon_proc_init)
+ mrc p15, 0, r0, c0, c0, 1 @ read cache type register
+ ldr r1, __cache_params
+ mov r2, #(16 << 5)
+ tst r0, #(1 << 16) @ get way
+ mov r0, r0, lsr #18 @ get cache size order
+ movne r3, #((4 - 1) << 30) @ 4-way
+ and r0, r0, #0xf
+ moveq r3, #0 @ 1-way
+ mov r2, r2, lsl r0 @ actual cache size
+ movne r2, r2, lsr #2 @ turned into # of sets
+ sub r2, r2, #(1 << 5)
+ stmia r1, {r2, r3}
+ ret lr
+
+/*
+ * cpu_feroceon_proc_fin()
+ */
+ENTRY(cpu_feroceon_proc_fin)
+#if defined(CONFIG_CACHE_FEROCEON_L2) && \
+ !defined(CONFIG_CACHE_FEROCEON_L2_WRITETHROUGH)
+ mov r0, #0
+ mcr p15, 1, r0, c15, c9, 0 @ clean L2
+ mcr p15, 0, r0, c7, c10, 4 @ drain WB
+#endif
+
+ mrc p15, 0, r0, c1, c0, 0 @ ctrl register
+ bic r0, r0, #0x1000 @ ...i............
+ bic r0, r0, #0x000e @ ............wca.
+ mcr p15, 0, r0, c1, c0, 0 @ disable caches
+ ret lr
+
+/*
+ * cpu_feroceon_reset(loc)
+ *
+ * Perform a soft reset of the system. Put the CPU into the
+ * same state as it would be if it had been reset, and branch
+ * to what would be the reset vector.
+ *
+ * loc: location to jump to for soft reset
+ */
+ .align 5
+ .pushsection .idmap.text, "ax"
+ENTRY(cpu_feroceon_reset)
+ mov ip, #0
+ mcr p15, 0, ip, c7, c7, 0 @ invalidate I,D caches
+ mcr p15, 0, ip, c7, c10, 4 @ drain WB
+#ifdef CONFIG_MMU
+ mcr p15, 0, ip, c8, c7, 0 @ invalidate I & D TLBs
+#endif
+ mrc p15, 0, ip, c1, c0, 0 @ ctrl register
+ bic ip, ip, #0x000f @ ............wcam
+ bic ip, ip, #0x1100 @ ...i...s........
+ mcr p15, 0, ip, c1, c0, 0 @ ctrl register
+ ret r0
+ENDPROC(cpu_feroceon_reset)
+ .popsection
+
+/*
+ * cpu_feroceon_do_idle()
+ *
+ * Called with IRQs disabled
+ */
+ .align 5
+ENTRY(cpu_feroceon_do_idle)
+ mov r0, #0
+ mcr p15, 0, r0, c7, c10, 4 @ Drain write buffer
+ mcr p15, 0, r0, c7, c0, 4 @ Wait for interrupt
+ ret lr
+
+/*
+ * flush_icache_all()
+ *
+ * Unconditionally clean and invalidate the entire icache.
+ */
+ENTRY(feroceon_flush_icache_all)
+ mov r0, #0
+ mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
+ ret lr
+ENDPROC(feroceon_flush_icache_all)
+
+/*
+ * flush_user_cache_all()
+ *
+ * Clean and invalidate all cache entries in a particular
+ * address space.
+ */
+ .align 5
+ENTRY(feroceon_flush_user_cache_all)
+ /* FALLTHROUGH */
+
+/*
+ * flush_kern_cache_all()
+ *
+ * Clean and invalidate the entire cache.
+ */
+ENTRY(feroceon_flush_kern_cache_all)
+ mov r2, #VM_EXEC
+
+__flush_whole_cache:
+ ldr r1, __cache_params
+ ldmia r1, {r1, r3}
+1: orr ip, r1, r3
+2: mcr p15, 0, ip, c7, c14, 2 @ clean + invalidate D set/way
+ subs ip, ip, #(1 << 30) @ next way
+ bcs 2b
+ subs r1, r1, #(1 << 5) @ next set
+ bcs 1b
+
+ tst r2, #VM_EXEC
+ mov ip, #0
+ mcrne p15, 0, ip, c7, c5, 0 @ invalidate I cache
+ mcrne p15, 0, ip, c7, c10, 4 @ drain WB
+ ret lr
+
+/*
+ * flush_user_cache_range(start, end, flags)
+ *
+ * Clean and invalidate a range of cache entries in the
+ * specified address range.
+ *
+ * - start - start address (inclusive)
+ * - end - end address (exclusive)
+ * - flags - vm_flags describing address space
+ */
+ .align 5
+ENTRY(feroceon_flush_user_cache_range)
+ sub r3, r1, r0 @ calculate total size
+ cmp r3, #CACHE_DLIMIT
+ bgt __flush_whole_cache
+1: tst r2, #VM_EXEC
+ mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D entry
+ mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry
+ add r0, r0, #CACHE_DLINESIZE
+ mcr p15, 0, r0, c7, c14, 1 @ clean and invalidate D entry
+ mcrne p15, 0, r0, c7, c5, 1 @ invalidate I entry
+ add r0, r0, #CACHE_DLINESIZE
+ cmp r0, r1
+ blo 1b
+ tst r2, #VM_EXEC
+ mov ip, #0
+ mcrne p15, 0, ip, c7, c10, 4 @ drain WB
+ ret lr
+
+/*
+ * coherent_kern_range(start, end)
+ *
+ * Ensure coherency between the Icache and the Dcache in the
+ * region described by start, end. If you have non-snooping
+ * Harvard caches, you need to implement this function.
+ *
+ * - start - virtual start address
+ * - end - virtual end address
+ */
+ .align 5
+ENTRY(feroceon_coherent_kern_range)
+ /* FALLTHROUGH */
+
+/*
+ * coherent_user_range(start, end)
+ *
+ * Ensure coherency between the Icache and the Dcache in the
+ * region described by start, end. If you have non-snooping
+ * Harvard caches, you need to implement this function.
+ *
+ * - start - virtual start address
+ * - end - virtual end address
+ */
+ENTRY(feroceon_coherent_user_range)
+ bic r0, r0, #CACHE_DLINESIZE - 1
+1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
+ mcr p15, 0, r0, c7, c5, 1 @ invalidate I entry
+ add r0, r0, #CACHE_DLINESIZE
+ cmp r0, r1
+ blo 1b
+ mcr p15, 0, r0, c7, c10, 4 @ drain WB
+ mov r0, #0
+ ret lr
+
+/*
+ * flush_kern_dcache_area(void *addr, size_t size)
+ *
+ * Ensure no D cache aliasing occurs, either with itself or
+ * the I cache
+ *
+ * - addr - kernel address
+ * - size - region size
+ */
+ .align 5
+ENTRY(feroceon_flush_kern_dcache_area)
+ add r1, r0, r1
+1: mcr p15, 0, r0, c7, c14, 1 @ clean+invalidate D entry
+ add r0, r0, #CACHE_DLINESIZE
+ cmp r0, r1
+ blo 1b
+ mov r0, #0
+ mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
+ mcr p15, 0, r0, c7, c10, 4 @ drain WB
+ ret lr
+
+ .align 5
+ENTRY(feroceon_range_flush_kern_dcache_area)
+ mrs r2, cpsr
+ add r1, r0, #PAGE_SZ - CACHE_DLINESIZE @ top addr is inclusive
+ orr r3, r2, #PSR_I_BIT
+ msr cpsr_c, r3 @ disable interrupts
+ mcr p15, 5, r0, c15, c15, 0 @ D clean/inv range start
+ mcr p15, 5, r1, c15, c15, 1 @ D clean/inv range top
+ msr cpsr_c, r2 @ restore interrupts
+ mov r0, #0
+ mcr p15, 0, r0, c7, c5, 0 @ invalidate I cache
+ mcr p15, 0, r0, c7, c10, 4 @ drain WB
+ ret lr
+
+/*
+ * dma_inv_range(start, end)
+ *
+ * Invalidate (discard) the specified virtual address range.
+ * May not write back any entries. If 'start' or 'end'
+ * are not cache line aligned, those lines must be written
+ * back.
+ *
+ * - start - virtual start address
+ * - end - virtual end address
+ *
+ * (same as v4wb)
+ */
+ .align 5
+feroceon_dma_inv_range:
+ tst r0, #CACHE_DLINESIZE - 1
+ bic r0, r0, #CACHE_DLINESIZE - 1
+ mcrne p15, 0, r0, c7, c10, 1 @ clean D entry
+ tst r1, #CACHE_DLINESIZE - 1
+ mcrne p15, 0, r1, c7, c10, 1 @ clean D entry
+1: mcr p15, 0, r0, c7, c6, 1 @ invalidate D entry
+ add r0, r0, #CACHE_DLINESIZE
+ cmp r0, r1
+ blo 1b
+ mcr p15, 0, r0, c7, c10, 4 @ drain WB
+ ret lr
+
+ .align 5
+feroceon_range_dma_inv_range:
+ mrs r2, cpsr
+ tst r0, #CACHE_DLINESIZE - 1
+ mcrne p15, 0, r0, c7, c10, 1 @ clean D entry
+ tst r1, #CACHE_DLINESIZE - 1
+ mcrne p15, 0, r1, c7, c10, 1 @ clean D entry
+ cmp r1, r0
+ subne r1, r1, #1 @ top address is inclusive
+ orr r3, r2, #PSR_I_BIT
+ msr cpsr_c, r3 @ disable interrupts
+ mcr p15, 5, r0, c15, c14, 0 @ D inv range start
+ mcr p15, 5, r1, c15, c14, 1 @ D inv range top
+ msr cpsr_c, r2 @ restore interrupts
+ ret lr
+
+/*
+ * dma_clean_range(start, end)
+ *
+ * Clean the specified virtual address range.
+ *
+ * - start - virtual start address
+ * - end - virtual end address
+ *
+ * (same as v4wb)
+ */
+ .align 5
+feroceon_dma_clean_range:
+ bic r0, r0, #CACHE_DLINESIZE - 1
+1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
+ add r0, r0, #CACHE_DLINESIZE
+ cmp r0, r1
+ blo 1b
+ mcr p15, 0, r0, c7, c10, 4 @ drain WB
+ ret lr
+
+ .align 5
+feroceon_range_dma_clean_range:
+ mrs r2, cpsr
+ cmp r1, r0
+ subne r1, r1, #1 @ top address is inclusive
+ orr r3, r2, #PSR_I_BIT
+ msr cpsr_c, r3 @ disable interrupts
+ mcr p15, 5, r0, c15, c13, 0 @ D clean range start
+ mcr p15, 5, r1, c15, c13, 1 @ D clean range top
+ msr cpsr_c, r2 @ restore interrupts
+ mcr p15, 0, r0, c7, c10, 4 @ drain WB
+ ret lr
+
+/*
+ * dma_flush_range(start, end)
+ *
+ * Clean and invalidate the specified virtual address range.
+ *
+ * - start - virtual start address
+ * - end - virtual end address
+ */
+ .align 5
+ENTRY(feroceon_dma_flush_range)
+ bic r0, r0, #CACHE_DLINESIZE - 1
+1: mcr p15, 0, r0, c7, c14, 1 @ clean+invalidate D entry
+ add r0, r0, #CACHE_DLINESIZE
+ cmp r0, r1
+ blo 1b
+ mcr p15, 0, r0, c7, c10, 4 @ drain WB
+ ret lr
+
+ .align 5
+ENTRY(feroceon_range_dma_flush_range)
+ mrs r2, cpsr
+ cmp r1, r0
+ subne r1, r1, #1 @ top address is inclusive
+ orr r3, r2, #PSR_I_BIT
+ msr cpsr_c, r3 @ disable interrupts
+ mcr p15, 5, r0, c15, c15, 0 @ D clean/inv range start
+ mcr p15, 5, r1, c15, c15, 1 @ D clean/inv range top
+ msr cpsr_c, r2 @ restore interrupts
+ mcr p15, 0, r0, c7, c10, 4 @ drain WB
+ ret lr
+
+/*
+ * dma_map_area(start, size, dir)
+ * - start - kernel virtual start address
+ * - size - size of region
+ * - dir - DMA direction
+ */
+ENTRY(feroceon_dma_map_area)
+ add r1, r1, r0
+ cmp r2, #DMA_TO_DEVICE
+ beq feroceon_dma_clean_range
+ bcs feroceon_dma_inv_range
+ b feroceon_dma_flush_range
+ENDPROC(feroceon_dma_map_area)
+
+/*
+ * dma_map_area(start, size, dir)
+ * - start - kernel virtual start address
+ * - size - size of region
+ * - dir - DMA direction
+ */
+ENTRY(feroceon_range_dma_map_area)
+ add r1, r1, r0
+ cmp r2, #DMA_TO_DEVICE
+ beq feroceon_range_dma_clean_range
+ bcs feroceon_range_dma_inv_range
+ b feroceon_range_dma_flush_range
+ENDPROC(feroceon_range_dma_map_area)
+
+/*
+ * dma_unmap_area(start, size, dir)
+ * - start - kernel virtual start address
+ * - size - size of region
+ * - dir - DMA direction
+ */
+ENTRY(feroceon_dma_unmap_area)
+ ret lr
+ENDPROC(feroceon_dma_unmap_area)
+
+ .globl feroceon_flush_kern_cache_louis
+ .equ feroceon_flush_kern_cache_louis, feroceon_flush_kern_cache_all
+
+ @ define struct cpu_cache_fns (see <asm/cacheflush.h> and proc-macros.S)
+ define_cache_functions feroceon
+
+.macro range_alias basename
+ .globl feroceon_range_\basename
+ .type feroceon_range_\basename , %function
+ .equ feroceon_range_\basename , feroceon_\basename
+.endm
+
+/*
+ * Most of the cache functions are unchanged for this case.
+ * Export suitable alias symbols for the unchanged functions:
+ */
+ range_alias flush_icache_all
+ range_alias flush_user_cache_all
+ range_alias flush_kern_cache_all
+ range_alias flush_kern_cache_louis
+ range_alias flush_user_cache_range
+ range_alias coherent_kern_range
+ range_alias coherent_user_range
+ range_alias dma_unmap_area
+
+ define_cache_functions feroceon_range
+
+ .align 5
+ENTRY(cpu_feroceon_dcache_clean_area)
+#if defined(CONFIG_CACHE_FEROCEON_L2) && \
+ !defined(CONFIG_CACHE_FEROCEON_L2_WRITETHROUGH)
+ mov r2, r0
+ mov r3, r1
+#endif
+1: mcr p15, 0, r0, c7, c10, 1 @ clean D entry
+ add r0, r0, #CACHE_DLINESIZE
+ subs r1, r1, #CACHE_DLINESIZE
+ bhi 1b
+#if defined(CONFIG_CACHE_FEROCEON_L2) && \
+ !defined(CONFIG_CACHE_FEROCEON_L2_WRITETHROUGH)
+1: mcr p15, 1, r2, c15, c9, 1 @ clean L2 entry
+ add r2, r2, #CACHE_DLINESIZE
+ subs r3, r3, #CACHE_DLINESIZE
+ bhi 1b
+#endif
+ mcr p15, 0, r0, c7, c10, 4 @ drain WB
+ ret lr
+
+/* =============================== PageTable ============================== */
+
+/*
+ * cpu_feroceon_switch_mm(pgd)
+ *
+ * Set the translation base pointer to be as described by pgd.
+ *
+ * pgd: new page tables
+ */
+ .align 5
+ENTRY(cpu_feroceon_switch_mm)
+#ifdef CONFIG_MMU
+ /*
+ * Note: we wish to call __flush_whole_cache but we need to preserve
+ * lr to do so. The only way without touching main memory is to
+ * use r2 which is normally used to test the VM_EXEC flag, and
+ * compensate locally for the skipped ops if it is not set.
+ */
+ mov r2, lr @ abuse r2 to preserve lr
+ bl __flush_whole_cache
+ @ if r2 contains the VM_EXEC bit then the next 2 ops are done already
+ tst r2, #VM_EXEC
+ mcreq p15, 0, ip, c7, c5, 0 @ invalidate I cache
+ mcreq p15, 0, ip, c7, c10, 4 @ drain WB
+
+ mcr p15, 0, r0, c2, c0, 0 @ load page table pointer
+ mcr p15, 0, ip, c8, c7, 0 @ invalidate I & D TLBs
+ ret r2
+#else
+ ret lr
+#endif
+
+/*
+ * cpu_feroceon_set_pte_ext(ptep, pte, ext)
+ *
+ * Set a PTE and flush it out
+ */
+ .align 5
+ENTRY(cpu_feroceon_set_pte_ext)
+#ifdef CONFIG_MMU
+ armv3_set_pte_ext wc_disable=0
+ mov r0, r0
+ mcr p15, 0, r0, c7, c10, 1 @ clean D entry
+#if defined(CONFIG_CACHE_FEROCEON_L2) && \
+ !defined(CONFIG_CACHE_FEROCEON_L2_WRITETHROUGH)
+ mcr p15, 1, r0, c15, c9, 1 @ clean L2 entry
+#endif
+ mcr p15, 0, r0, c7, c10, 4 @ drain WB
+#endif
+ ret lr
+
+/* Suspend/resume support: taken from arch/arm/mm/proc-arm926.S */
+.globl cpu_feroceon_suspend_size
+.equ cpu_feroceon_suspend_size, 4 * 3
+#ifdef CONFIG_ARM_CPU_SUSPEND
+ENTRY(cpu_feroceon_do_suspend)
+ stmfd sp!, {r4 - r6, lr}
+ mrc p15, 0, r4, c13, c0, 0 @ PID
+ mrc p15, 0, r5, c3, c0, 0 @ Domain ID
+ mrc p15, 0, r6, c1, c0, 0 @ Control register
+ stmia r0, {r4 - r6}
+ ldmfd sp!, {r4 - r6, pc}
+ENDPROC(cpu_feroceon_do_suspend)
+
+ENTRY(cpu_feroceon_do_resume)
+ mov ip, #0
+ mcr p15, 0, ip, c8, c7, 0 @ invalidate I+D TLBs
+ mcr p15, 0, ip, c7, c7, 0 @ invalidate I+D caches
+ ldmia r0, {r4 - r6}
+ mcr p15, 0, r4, c13, c0, 0 @ PID
+ mcr p15, 0, r5, c3, c0, 0 @ Domain ID
+ mcr p15, 0, r1, c2, c0, 0 @ TTB address
+ mov r0, r6 @ control register
+ b cpu_resume_mmu
+ENDPROC(cpu_feroceon_do_resume)
+#endif
+
+ .type __feroceon_setup, #function
+__feroceon_setup:
+ mov r0, #0
+ mcr p15, 0, r0, c7, c7 @ invalidate I,D caches on v4
+ mcr p15, 0, r0, c7, c10, 4 @ drain write buffer on v4
+#ifdef CONFIG_MMU
+ mcr p15, 0, r0, c8, c7 @ invalidate I,D TLBs on v4
+#endif
+
+ adr r5, feroceon_crval
+ ldmia r5, {r5, r6}
+ mrc p15, 0, r0, c1, c0 @ get control register v4
+ bic r0, r0, r5
+ orr r0, r0, r6
+ ret lr
+ .size __feroceon_setup, . - __feroceon_setup
+
+ /*
+ * B
+ * R P
+ * .RVI UFRS BLDP WCAM
+ * .011 .001 ..11 0101
+ *
+ */
+ .type feroceon_crval, #object
+feroceon_crval:
+ crval clear=0x0000773f, mmuset=0x00003135, ucset=0x00001134
+
+ __INITDATA
+
+ @ define struct processor (see <asm/proc-fns.h> and proc-macros.S)
+ define_processor_functions feroceon, dabort=v5t_early_abort, pabort=legacy_pabort
+
+ .section ".rodata"
+
+ string cpu_arch_name, "armv5te"
+ string cpu_elf_name, "v5"
+ string cpu_feroceon_name, "Feroceon"
+ string cpu_88fr531_name, "Feroceon 88FR531-vd"
+ string cpu_88fr571_name, "Feroceon 88FR571-vd"
+ string cpu_88fr131_name, "Feroceon 88FR131"
+
+ .align
+
+ .section ".proc.info.init", #alloc
+
+.macro feroceon_proc_info name:req, cpu_val:req, cpu_mask:req, cpu_name:req, cache:req
+ .type __\name\()_proc_info,#object
+__\name\()_proc_info:
+ .long \cpu_val
+ .long \cpu_mask
+ .long PMD_TYPE_SECT | \
+ PMD_SECT_BUFFERABLE | \
+ PMD_SECT_CACHEABLE | \
+ PMD_BIT4 | \
+ PMD_SECT_AP_WRITE | \
+ PMD_SECT_AP_READ
+ .long PMD_TYPE_SECT | \
+ PMD_BIT4 | \
+ PMD_SECT_AP_WRITE | \
+ PMD_SECT_AP_READ
+ initfn __feroceon_setup, __\name\()_proc_info
+ .long cpu_arch_name
+ .long cpu_elf_name
+ .long HWCAP_SWP|HWCAP_HALF|HWCAP_THUMB|HWCAP_FAST_MULT|HWCAP_EDSP
+ .long \cpu_name
+ .long feroceon_processor_functions
+ .long v4wbi_tlb_fns
+ .long feroceon_user_fns
+ .long \cache
+ .size __\name\()_proc_info, . - __\name\()_proc_info
+.endm
+
+#ifdef CONFIG_CPU_FEROCEON_OLD_ID
+ feroceon_proc_info feroceon_old_id, 0x41009260, 0xff00fff0, \
+ cpu_name=cpu_feroceon_name, cache=feroceon_cache_fns
+#endif
+
+ feroceon_proc_info 88fr531, 0x56055310, 0xfffffff0, cpu_88fr531_name, \
+ cache=feroceon_cache_fns
+ feroceon_proc_info 88fr571, 0x56155710, 0xfffffff0, cpu_88fr571_name, \
+ cache=feroceon_range_cache_fns
+ feroceon_proc_info 88fr131, 0x56251310, 0xfffffff0, cpu_88fr131_name, \
+ cache=feroceon_range_cache_fns