nds32: Remove the architecture

The nds32 architecture, also known as AndeStar V3, is a custom 32-bit
RISC target designed by Andes Technologies. Support was added to the
kernel in 2016 as the replacement RISC-V based V5 processors were
already announced, and maintained by (current or former) Andes
employees.

As explained by Alan Kao, new customers are now all using RISC-V,
and all known nds32 users are already on longterm stable kernels
provided by Andes, with no development work going into mainline
support any more.

While the port is still in a reasonably good shape, it only gets
worse over time without active maintainers, so it seems best
to remove it before it becomes unusable. As always, if it turns
out that there are mainline users after all, and they volunteer
to maintain the port in the future, the removal can be reverted.

Link: https://lore.kernel.org/linux-mm/YhdWNLUhk+x9RAzU@yamatobi.andestech.com/
Link: https://lore.kernel.org/lkml/20220302065213.82702-1-alankao@andestech.com/
Link: https://www.andestech.com/en/products-solutions/andestar-architecture/
Signed-off-by: Alan Kao <alankao@andestech.com>
[arnd: rewrite changelog to provide more background]
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 0 insertions, 536 deletions

diff --git a/arch/nds32/mm/proc.c b/arch/nds32/mm/proc.c
deleted file mode 100644
index 848c845f5f33..000000000000
--- a/arch/nds32/mm/proc.c
+++ /dev/null
@@ -1,536 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0
-// Copyright (C) 2005-2017 Andes Technology Corporation
-
-#include <linux/module.h>
-#include <linux/sched.h>
-#include <linux/mm.h>
-#include <asm/nds32.h>
-#include <asm/tlbflush.h>
-#include <asm/cacheflush.h>
-#include <asm/l2_cache.h>
-#include <nds32_intrinsic.h>
-
-#include <asm/cache_info.h>
-extern struct cache_info L1_cache_info[2];
-
-int va_kernel_present(unsigned long addr)
-{
-	pmd_t *pmd;
-	pte_t *ptep, pte;
-
-	pmd = pmd_off_k(addr);
-	if (!pmd_none(*pmd)) {
-		ptep = pte_offset_map(pmd, addr);
-		pte = *ptep;
-		if (pte_present(pte))
-			return pte;
-	}
-	return 0;
-}
-
-pte_t va_present(struct mm_struct * mm, unsigned long addr)
-{
-	pgd_t *pgd;
-	p4d_t *p4d;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *ptep, pte;
-
-	pgd = pgd_offset(mm, addr);
-	if (!pgd_none(*pgd)) {
-		p4d = p4d_offset(pgd, addr);
-		if (!p4d_none(*p4d)) {
-			pud = pud_offset(p4d, addr);
-			if (!pud_none(*pud)) {
-				pmd = pmd_offset(pud, addr);
-				if (!pmd_none(*pmd)) {
-					ptep = pte_offset_map(pmd, addr);
-					pte = *ptep;
-					if (pte_present(pte))
-						return pte;
-				}
-			}
-		}
-	}
-	return 0;
-
-}
-
-int va_readable(struct pt_regs *regs, unsigned long addr)
-{
-	struct mm_struct *mm = current->mm;
-	pte_t pte;
-	int ret = 0;
-
-	if (user_mode(regs)) {
-		/* user mode */
-		pte = va_present(mm, addr);
-		if (!pte && pte_read(pte))
-			ret = 1;
-	} else {
-		/* superuser mode is always readable, so we can only
-		 * check it is present or not*/
-		return (! !va_kernel_present(addr));
-	}
-	return ret;
-}
-
-int va_writable(struct pt_regs *regs, unsigned long addr)
-{
-	struct mm_struct *mm = current->mm;
-	pte_t pte;
-	int ret = 0;
-
-	if (user_mode(regs)) {
-		/* user mode */
-		pte = va_present(mm, addr);
-		if (!pte && pte_write(pte))
-			ret = 1;
-	} else {
-		/* superuser mode */
-		pte = va_kernel_present(addr);
-		if (!pte && pte_kernel_write(pte))
-			ret = 1;
-	}
-	return ret;
-}
-
-/*
- * All
- */
-void cpu_icache_inval_all(void)
-{
-	unsigned long end, line_size;
-
-	line_size = L1_cache_info[ICACHE].line_size;
-	end =
-	    line_size * L1_cache_info[ICACHE].ways * L1_cache_info[ICACHE].sets;
-
-	do {
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1I_IX_INVAL"::"r" (end));
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1I_IX_INVAL"::"r" (end));
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1I_IX_INVAL"::"r" (end));
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1I_IX_INVAL"::"r" (end));
-	} while (end > 0);
-	__nds32__isb();
-}
-
-void cpu_dcache_inval_all(void)
-{
-	__nds32__cctl_l1d_invalall();
-}
-
-#ifdef CONFIG_CACHE_L2
-void dcache_wb_all_level(void)
-{
-	unsigned long flags, cmd;
-	local_irq_save(flags);
-	__nds32__cctl_l1d_wball_alvl();
-	/* Section 1: Ensure the section 2 & 3 program code execution after */
-	__nds32__cctlidx_read(NDS32_CCTL_L1D_IX_RWD,0);
-
-	/* Section 2: Confirm the writeback all level is done in CPU and L2C */
-	cmd = CCTL_CMD_L2_SYNC;
-	L2_CMD_RDY();
-	L2C_W_REG(L2_CCTL_CMD_OFF, cmd);
-	L2_CMD_RDY();
-
-	/* Section 3: Writeback whole L2 cache */
-	cmd = CCTL_ALL_CMD | CCTL_CMD_L2_IX_WB;
-	L2_CMD_RDY();
-	L2C_W_REG(L2_CCTL_CMD_OFF, cmd);
-	L2_CMD_RDY();
-	__nds32__msync_all();
-	local_irq_restore(flags);
-}
-EXPORT_SYMBOL(dcache_wb_all_level);
-#endif
-
-void cpu_dcache_wb_all(void)
-{
-	__nds32__cctl_l1d_wball_one_lvl();
-	__nds32__cctlidx_read(NDS32_CCTL_L1D_IX_RWD,0);
-}
-
-void cpu_dcache_wbinval_all(void)
-{
-#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
-	unsigned long flags;
-	local_irq_save(flags);
-#endif
-	cpu_dcache_wb_all();
-	cpu_dcache_inval_all();
-#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
-	local_irq_restore(flags);
-#endif
-}
-
-/*
- * Page
- */
-void cpu_icache_inval_page(unsigned long start)
-{
-	unsigned long line_size, end;
-
-	line_size = L1_cache_info[ICACHE].line_size;
-	end = start + PAGE_SIZE;
-
-	do {
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1I_VA_INVAL"::"r" (end));
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1I_VA_INVAL"::"r" (end));
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1I_VA_INVAL"::"r" (end));
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1I_VA_INVAL"::"r" (end));
-	} while (end != start);
-	__nds32__isb();
-}
-
-void cpu_dcache_inval_page(unsigned long start)
-{
-	unsigned long line_size, end;
-
-	line_size = L1_cache_info[DCACHE].line_size;
-	end = start + PAGE_SIZE;
-
-	do {
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_INVAL"::"r" (end));
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_INVAL"::"r" (end));
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_INVAL"::"r" (end));
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_INVAL"::"r" (end));
-	} while (end != start);
-}
-
-void cpu_dcache_wb_page(unsigned long start)
-{
-#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
-	unsigned long line_size, end;
-
-	line_size = L1_cache_info[DCACHE].line_size;
-	end = start + PAGE_SIZE;
-
-	do {
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_WB"::"r" (end));
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_WB"::"r" (end));
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_WB"::"r" (end));
-		end -= line_size;
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_WB"::"r" (end));
-	} while (end != start);
-	__nds32__cctlidx_read(NDS32_CCTL_L1D_IX_RWD,0);
-#endif
-}
-
-void cpu_dcache_wbinval_page(unsigned long start)
-{
-	unsigned long line_size, end;
-
-	line_size = L1_cache_info[DCACHE].line_size;
-	end = start + PAGE_SIZE;
-
-	do {
-		end -= line_size;
-#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_WB"::"r" (end));
-#endif
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_INVAL"::"r" (end));
-		end -= line_size;
-#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_WB"::"r" (end));
-#endif
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_INVAL"::"r" (end));
-		end -= line_size;
-#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_WB"::"r" (end));
-#endif
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_INVAL"::"r" (end));
-		end -= line_size;
-#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_WB"::"r" (end));
-#endif
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_INVAL"::"r" (end));
-	} while (end != start);
-	__nds32__cctlidx_read(NDS32_CCTL_L1D_IX_RWD,0);
-}
-
-void cpu_cache_wbinval_page(unsigned long page, int flushi)
-{
-	cpu_dcache_wbinval_page(page);
-	if (flushi)
-		cpu_icache_inval_page(page);
-}
-
-/*
- * Range
- */
-void cpu_icache_inval_range(unsigned long start, unsigned long end)
-{
-	unsigned long line_size;
-
-	line_size = L1_cache_info[ICACHE].line_size;
-
-	while (end > start) {
-		__asm__ volatile ("\n\tcctl %0, L1I_VA_INVAL"::"r" (start));
-		start += line_size;
-	}
-	__nds32__isb();
-}
-
-void cpu_dcache_inval_range(unsigned long start, unsigned long end)
-{
-	unsigned long line_size;
-
-	line_size = L1_cache_info[DCACHE].line_size;
-
-	while (end > start) {
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_INVAL"::"r" (start));
-		start += line_size;
-	}
-}
-
-void cpu_dcache_wb_range(unsigned long start, unsigned long end)
-{
-#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
-	unsigned long line_size;
-
-	line_size = L1_cache_info[DCACHE].line_size;
-
-	while (end > start) {
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_WB"::"r" (start));
-		start += line_size;
-	}
-	__nds32__cctlidx_read(NDS32_CCTL_L1D_IX_RWD,0);
-#endif
-}
-
-void cpu_dcache_wbinval_range(unsigned long start, unsigned long end)
-{
-	unsigned long line_size;
-
-	line_size = L1_cache_info[DCACHE].line_size;
-
-	while (end > start) {
-#ifndef CONFIG_CPU_DCACHE_WRITETHROUGH
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_WB"::"r" (start));
-#endif
-		__asm__ volatile ("\n\tcctl %0, L1D_VA_INVAL"::"r" (start));
-		start += line_size;
-	}
-	__nds32__cctlidx_read(NDS32_CCTL_L1D_IX_RWD,0);
-}
-
-void cpu_cache_wbinval_range(unsigned long start, unsigned long end, int flushi)
-{
-	unsigned long line_size, align_start, align_end;
-
-	line_size = L1_cache_info[DCACHE].line_size;
-	align_start = start & ~(line_size - 1);
-	align_end = (end + line_size - 1) & ~(line_size - 1);
-	cpu_dcache_wbinval_range(align_start, align_end);
-
-	if (flushi) {
-		line_size = L1_cache_info[ICACHE].line_size;
-		align_start = start & ~(line_size - 1);
-		align_end = (end + line_size - 1) & ~(line_size - 1);
-		cpu_icache_inval_range(align_start, align_end);
-	}
-}
-
-void cpu_cache_wbinval_range_check(struct vm_area_struct *vma,
-				   unsigned long start, unsigned long end,
-				   bool flushi, bool wbd)
-{
-	unsigned long line_size, t_start, t_end;
-
-	if (!flushi && !wbd)
-		return;
-	line_size = L1_cache_info[DCACHE].line_size;
-	start = start & ~(line_size - 1);
-	end = (end + line_size - 1) & ~(line_size - 1);
-
-	if ((end - start) > (8 * PAGE_SIZE)) {
-		if (wbd)
-			cpu_dcache_wbinval_all();
-		if (flushi)
-			cpu_icache_inval_all();
-		return;
-	}
-
-	t_start = (start + PAGE_SIZE) & PAGE_MASK;
-	t_end = ((end - 1) & PAGE_MASK);
-
-	if ((start & PAGE_MASK) == t_end) {
-		if (va_present(vma->vm_mm, start)) {
-			if (wbd)
-				cpu_dcache_wbinval_range(start, end);
-			if (flushi)
-				cpu_icache_inval_range(start, end);
-		}
-		return;
-	}
-
-	if (va_present(vma->vm_mm, start)) {
-		if (wbd)
-			cpu_dcache_wbinval_range(start, t_start);
-		if (flushi)
-			cpu_icache_inval_range(start, t_start);
-	}
-
-	if (va_present(vma->vm_mm, end - 1)) {
-		if (wbd)
-			cpu_dcache_wbinval_range(t_end, end);
-		if (flushi)
-			cpu_icache_inval_range(t_end, end);
-	}
-
-	while (t_start < t_end) {
-		if (va_present(vma->vm_mm, t_start)) {
-			if (wbd)
-				cpu_dcache_wbinval_page(t_start);
-			if (flushi)
-				cpu_icache_inval_page(t_start);
-		}
-		t_start += PAGE_SIZE;
-	}
-}
-
-#ifdef CONFIG_CACHE_L2
-static inline void cpu_l2cache_op(unsigned long start, unsigned long end, unsigned long op)
-{
-	if (atl2c_base) {
-		unsigned long p_start = __pa(start);
-		unsigned long p_end = __pa(end);
-		unsigned long cmd;
-		unsigned long line_size;
-		/* TODO Can Use PAGE Mode to optimize if range large than PAGE_SIZE */
-		line_size = L2_CACHE_LINE_SIZE();
-		p_start = p_start & (~(line_size - 1));
-		p_end = (p_end + line_size - 1) & (~(line_size - 1));
-		cmd =
-		    (p_start & ~(line_size - 1)) | op |
-		    CCTL_SINGLE_CMD;
-		do {
-			L2_CMD_RDY();
-			L2C_W_REG(L2_CCTL_CMD_OFF, cmd);
-			cmd += line_size;
-			p_start += line_size;
-		} while (p_end > p_start);
-		cmd = CCTL_CMD_L2_SYNC;
-		L2_CMD_RDY();
-		L2C_W_REG(L2_CCTL_CMD_OFF, cmd);
-		L2_CMD_RDY();
-	}
-}
-#else
-#define cpu_l2cache_op(start,end,op) do { } while (0)
-#endif
-/*
- * DMA
- */
-void cpu_dma_wb_range(unsigned long start, unsigned long end)
-{
-	unsigned long line_size;
-	unsigned long flags;
-	line_size = L1_cache_info[DCACHE].line_size;
-	start = start & (~(line_size - 1));
-	end = (end + line_size - 1) & (~(line_size - 1));
-	if (unlikely(start == end))
-		return;
-
-	local_irq_save(flags);
-	cpu_dcache_wb_range(start, end);
-	cpu_l2cache_op(start, end, CCTL_CMD_L2_PA_WB);
-	__nds32__msync_all();
-	local_irq_restore(flags);
-}
-
-void cpu_dma_inval_range(unsigned long start, unsigned long end)
-{
-	unsigned long line_size;
-	unsigned long old_start = start;
-	unsigned long old_end = end;
-	unsigned long flags;
-	line_size = L1_cache_info[DCACHE].line_size;
-	start = start & (~(line_size - 1));
-	end = (end + line_size - 1) & (~(line_size - 1));
-	if (unlikely(start == end))
-		return;
-	local_irq_save(flags);
-	if (start != old_start) {
-		cpu_dcache_wbinval_range(start, start + line_size);
-		cpu_l2cache_op(start, start + line_size, CCTL_CMD_L2_PA_WBINVAL);
-	}
-	if (end != old_end) {
-		cpu_dcache_wbinval_range(end - line_size, end);
-		cpu_l2cache_op(end - line_size, end, CCTL_CMD_L2_PA_WBINVAL);
-	}
-	cpu_dcache_inval_range(start, end);
-	cpu_l2cache_op(start, end, CCTL_CMD_L2_PA_INVAL);
-	__nds32__msync_all();
-	local_irq_restore(flags);
-
-}
-
-void cpu_dma_wbinval_range(unsigned long start, unsigned long end)
-{
-	unsigned long line_size;
-	unsigned long flags;
-	line_size = L1_cache_info[DCACHE].line_size;
-	start = start & (~(line_size - 1));
-	end = (end + line_size - 1) & (~(line_size - 1));
-	if (unlikely(start == end))
-		return;
-
-	local_irq_save(flags);
-	cpu_dcache_wbinval_range(start, end);
-	cpu_l2cache_op(start, end, CCTL_CMD_L2_PA_WBINVAL);
-	__nds32__msync_all();
-	local_irq_restore(flags);
-}
-
-void cpu_proc_init(void)
-{
-}
-
-void cpu_proc_fin(void)
-{
-}
-
-void cpu_do_idle(void)
-{
-	__nds32__standby_no_wake_grant();
-}
-
-void cpu_reset(unsigned long reset)
-{
-	u32 tmp;
-	GIE_DISABLE();
-	tmp = __nds32__mfsr(NDS32_SR_CACHE_CTL);
-	tmp &= ~(CACHE_CTL_mskIC_EN | CACHE_CTL_mskDC_EN);
-	__nds32__mtsr_isb(tmp, NDS32_SR_CACHE_CTL);
-	cpu_dcache_wbinval_all();
-	cpu_icache_inval_all();
-
-	__asm__ __volatile__("jr.toff %0\n\t"::"r"(reset));
-}
-
-void cpu_switch_mm(struct mm_struct *mm)
-{
-	unsigned long cid;
-	cid = __nds32__mfsr(NDS32_SR_TLB_MISC);
-	cid = (cid & ~TLB_MISC_mskCID) | mm->context.id;
-	__nds32__mtsr_dsb(cid, NDS32_SR_TLB_MISC);
-	__nds32__mtsr_isb(__pa(mm->pgd), NDS32_SR_L1_PPTB);
-}