c6x: remove architecture

The c6x architecture was added to the kernel in 2011 at a time when
running Linux on DSPs was widely seen as the logical evolution.
It appears the trend has gone back to running Linux on Arm based SoCs
with DSP, using a better supported software ecosystem, and having better
real-time behavior for the DSP code. An example of this is TI's own
Keystone2 platform.

The upstream kernel port appears to no longer have any users. Mark
Salter remained avaialable to review patches, but mentioned that
he no longer has access to working hardware himself. Without any
users, it's best to just remove the code completely to reduce the
work for cross-architecture code changes.

Many thanks to Mark for maintaining the code for the past ten years.

Link: https://lore.kernel.org/lkml/41dc7795afda9f776d8cd0d3075f776cf586e97c.camel@redhat.com/
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

1 files changed, 0 insertions, 151 deletions

diff --git a/arch/c6x/kernel/process.c b/arch/c6x/kernel/process.c
deleted file mode 100644
index 9f4fd6a40a10..000000000000
--- a/arch/c6x/kernel/process.c
+++ /dev/null
@@ -1,151 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- *  Port on Texas Instruments TMS320C6x architecture
- *
- *  Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
- *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.com)
- */
-#include <linux/module.h>
-#include <linux/unistd.h>
-#include <linux/ptrace.h>
-#include <linux/init_task.h>
-#include <linux/tick.h>
-#include <linux/mqueue.h>
-#include <linux/syscalls.h>
-#include <linux/reboot.h>
-#include <linux/sched/task.h>
-#include <linux/sched/task_stack.h>
-
-#include <asm/syscalls.h>
-
-/* hooks for board specific support */
-void	(*c6x_restart)(void);
-void	(*c6x_halt)(void);
-
-extern asmlinkage void ret_from_fork(void);
-extern asmlinkage void ret_from_kernel_thread(void);
-
-/*
- * power off function, if any
- */
-void (*pm_power_off)(void);
-EXPORT_SYMBOL(pm_power_off);
-
-void arch_cpu_idle(void)
-{
-	unsigned long tmp;
-
-	/*
-	 * Put local_irq_enable and idle in same execute packet
-	 * to make them atomic and avoid race to idle with
-	 * interrupts enabled.
-	 */
-	asm volatile ("   mvc .s2 CSR,%0\n"
-		      "   or  .d2 1,%0,%0\n"
-		      "   mvc .s2 %0,CSR\n"
-		      "|| idle\n"
-		      : "=b"(tmp));
-}
-
-static void halt_loop(void)
-{
-	printk(KERN_EMERG "System Halted, OK to turn off power\n");
-	local_irq_disable();
-	while (1)
-		asm volatile("idle\n");
-}
-
-void machine_restart(char *__unused)
-{
-	if (c6x_restart)
-		c6x_restart();
-	halt_loop();
-}
-
-void machine_halt(void)
-{
-	if (c6x_halt)
-		c6x_halt();
-	halt_loop();
-}
-
-void machine_power_off(void)
-{
-	if (pm_power_off)
-		pm_power_off();
-	halt_loop();
-}
-
-void flush_thread(void)
-{
-}
-
-/*
- * Do necessary setup to start up a newly executed thread.
- */
-void start_thread(struct pt_regs *regs, unsigned int pc, unsigned long usp)
-{
-	/*
-	 * The binfmt loader will setup a "full" stack, but the C6X
-	 * operates an "empty" stack. So we adjust the usp so that
-	 * argc doesn't get destroyed if an interrupt is taken before
-	 * it is read from the stack.
-	 *
-	 * NB: Library startup code needs to match this.
-	 */
-	usp -= 8;
-
-	regs->pc  = pc;
-	regs->sp  = usp;
-	regs->tsr |= 0x40; /* set user mode */
-	current->thread.usp = usp;
-}
-
-/*
- * Copy a new thread context in its stack.
- */
-int copy_thread(unsigned long clone_flags, unsigned long usp,
-		unsigned long ustk_size, struct task_struct *p,
-		unsigned long tls)
-{
-	struct pt_regs *childregs;
-
-	childregs = task_pt_regs(p);
-
-	if (unlikely(p->flags & PF_KTHREAD)) {
-		/* case of  __kernel_thread: we return to supervisor space */
-		memset(childregs, 0, sizeof(struct pt_regs));
-		childregs->sp = (unsigned long)(childregs + 1);
-		p->thread.pc = (unsigned long) ret_from_kernel_thread;
-		childregs->a0 = usp;		/* function */
-		childregs->a1 = ustk_size;	/* argument */
-	} else {
-		/* Otherwise use the given stack */
-		*childregs = *current_pt_regs();
-		if (usp)
-			childregs->sp = usp;
-		p->thread.pc = (unsigned long) ret_from_fork;
-	}
-
-	/* Set usp/ksp */
-	p->thread.usp = childregs->sp;
-	thread_saved_ksp(p) = (unsigned long)childregs - 8;
-	p->thread.wchan	= p->thread.pc;
-#ifdef __DSBT__
-	{
-		unsigned long dp;
-
-		asm volatile ("mv .S2 b14,%0\n" : "=b"(dp));
-
-		thread_saved_dp(p) = dp;
-		if (usp == -1)
-			childregs->dp = dp;
-	}
-#endif
-	return 0;
-}
-
-unsigned long get_wchan(struct task_struct *p)
-{
-	return p->thread.wchan;
-}