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, 344 deletions

diff --git a/arch/c6x/platforms/megamod-pic.c b/arch/c6x/platforms/megamod-pic.c
deleted file mode 100644
index 56189e50728c..000000000000
--- a/arch/c6x/platforms/megamod-pic.c
+++ /dev/null
@@ -1,344 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/*
- *  Support for C64x+ Megamodule Interrupt Controller
- *
- *  Copyright (C) 2010, 2011 Texas Instruments Incorporated
- *  Contributed by: Mark Salter <msalter@redhat.com>
- */
-#include <linux/module.h>
-#include <linux/interrupt.h>
-#include <linux/io.h>
-#include <linux/of.h>
-#include <linux/of_irq.h>
-#include <linux/of_address.h>
-#include <linux/slab.h>
-#include <asm/soc.h>
-#include <asm/megamod-pic.h>
-
-#define NR_COMBINERS	4
-#define NR_MUX_OUTPUTS  12
-
-#define IRQ_UNMAPPED 0xffff
-
-/*
- * Megamodule Interrupt Controller register layout
- */
-struct megamod_regs {
-	u32	evtflag[8];
-	u32	evtset[8];
-	u32	evtclr[8];
-	u32	reserved0[8];
-	u32	evtmask[8];
-	u32	mevtflag[8];
-	u32	expmask[8];
-	u32	mexpflag[8];
-	u32	intmux_unused;
-	u32	intmux[7];
-	u32	reserved1[8];
-	u32	aegmux[2];
-	u32	reserved2[14];
-	u32	intxstat;
-	u32	intxclr;
-	u32	intdmask;
-	u32	reserved3[13];
-	u32	evtasrt;
-};
-
-struct megamod_pic {
-	struct irq_domain *irqhost;
-	struct megamod_regs __iomem *regs;
-	raw_spinlock_t lock;
-
-	/* hw mux mapping */
-	unsigned int output_to_irq[NR_MUX_OUTPUTS];
-};
-
-static struct megamod_pic *mm_pic;
-
-struct megamod_cascade_data {
-	struct megamod_pic *pic;
-	int index;
-};
-
-static struct megamod_cascade_data cascade_data[NR_COMBINERS];
-
-static void mask_megamod(struct irq_data *data)
-{
-	struct megamod_pic *pic = irq_data_get_irq_chip_data(data);
-	irq_hw_number_t src = irqd_to_hwirq(data);
-	u32 __iomem *evtmask = &pic->regs->evtmask[src / 32];
-
-	raw_spin_lock(&pic->lock);
-	soc_writel(soc_readl(evtmask) | (1 << (src & 31)), evtmask);
-	raw_spin_unlock(&pic->lock);
-}
-
-static void unmask_megamod(struct irq_data *data)
-{
-	struct megamod_pic *pic = irq_data_get_irq_chip_data(data);
-	irq_hw_number_t src = irqd_to_hwirq(data);
-	u32 __iomem *evtmask = &pic->regs->evtmask[src / 32];
-
-	raw_spin_lock(&pic->lock);
-	soc_writel(soc_readl(evtmask) & ~(1 << (src & 31)), evtmask);
-	raw_spin_unlock(&pic->lock);
-}
-
-static struct irq_chip megamod_chip = {
-	.name		= "megamod",
-	.irq_mask	= mask_megamod,
-	.irq_unmask	= unmask_megamod,
-};
-
-static void megamod_irq_cascade(struct irq_desc *desc)
-{
-	struct megamod_cascade_data *cascade;
-	struct megamod_pic *pic;
-	unsigned int irq;
-	u32 events;
-	int n, idx;
-
-	cascade = irq_desc_get_handler_data(desc);
-
-	pic = cascade->pic;
-	idx = cascade->index;
-
-	while ((events = soc_readl(&pic->regs->mevtflag[idx])) != 0) {
-		n = __ffs(events);
-
-		irq = irq_linear_revmap(pic->irqhost, idx * 32 + n);
-
-		soc_writel(1 << n, &pic->regs->evtclr[idx]);
-
-		generic_handle_irq(irq);
-	}
-}
-
-static int megamod_map(struct irq_domain *h, unsigned int virq,
-		       irq_hw_number_t hw)
-{
-	struct megamod_pic *pic = h->host_data;
-	int i;
-
-	/* We shouldn't see a hwirq which is muxed to core controller */
-	for (i = 0; i < NR_MUX_OUTPUTS; i++)
-		if (pic->output_to_irq[i] == hw)
-			return -1;
-
-	irq_set_chip_data(virq, pic);
-	irq_set_chip_and_handler(virq, &megamod_chip, handle_level_irq);
-
-	/* Set default irq type */
-	irq_set_irq_type(virq, IRQ_TYPE_NONE);
-
-	return 0;
-}
-
-static const struct irq_domain_ops megamod_domain_ops = {
-	.map	= megamod_map,
-	.xlate	= irq_domain_xlate_onecell,
-};
-
-static void __init set_megamod_mux(struct megamod_pic *pic, int src, int output)
-{
-	int index, offset;
-	u32 val;
-
-	if (src < 0 || src >= (NR_COMBINERS * 32)) {
-		pic->output_to_irq[output] = IRQ_UNMAPPED;
-		return;
-	}
-
-	/* four mappings per mux register */
-	index = output / 4;
-	offset = (output & 3) * 8;
-
-	val = soc_readl(&pic->regs->intmux[index]);
-	val &= ~(0xff << offset);
-	val |= src << offset;
-	soc_writel(val, &pic->regs->intmux[index]);
-}
-
-/*
- * Parse the MUX mapping, if one exists.
- *
- * The MUX map is an array of up to 12 cells; one for each usable core priority
- * interrupt. The value of a given cell is the megamodule interrupt source
- * which is to me MUXed to the output corresponding to the cell position
- * withing the array. The first cell in the array corresponds to priority
- * 4 and the last (12th) cell corresponds to priority 15. The allowed
- * values are 4 - ((NR_COMBINERS * 32) - 1). Note that the combined interrupt
- * sources (0 - 3) are not allowed to be mapped through this property. They
- * are handled through the "interrupts" property. This allows us to use a
- * value of zero as a "do not map" placeholder.
- */
-static void __init parse_priority_map(struct megamod_pic *pic,
-				      int *mapping, int size)
-{
-	struct device_node *np = irq_domain_get_of_node(pic->irqhost);
-	const __be32 *map;
-	int i, maplen;
-	u32 val;
-
-	map = of_get_property(np, "ti,c64x+megamod-pic-mux", &maplen);
-	if (map) {
-		maplen /= 4;
-		if (maplen > size)
-			maplen = size;
-
-		for (i = 0; i < maplen; i++) {
-			val = be32_to_cpup(map);
-			if (val && val >= 4)
-				mapping[i] = val;
-			++map;
-		}
-	}
-}
-
-static struct megamod_pic * __init init_megamod_pic(struct device_node *np)
-{
-	struct megamod_pic *pic;
-	int i, irq;
-	int mapping[NR_MUX_OUTPUTS];
-
-	pr_info("Initializing C64x+ Megamodule PIC\n");
-
-	pic = kzalloc(sizeof(struct megamod_pic), GFP_KERNEL);
-	if (!pic) {
-		pr_err("%pOF: Could not alloc PIC structure.\n", np);
-		return NULL;
-	}
-
-	pic->irqhost = irq_domain_add_linear(np, NR_COMBINERS * 32,
-					     &megamod_domain_ops, pic);
-	if (!pic->irqhost) {
-		pr_err("%pOF: Could not alloc host.\n", np);
-		goto error_free;
-	}
-
-	pic->irqhost->host_data = pic;
-
-	raw_spin_lock_init(&pic->lock);
-
-	pic->regs = of_iomap(np, 0);
-	if (!pic->regs) {
-		pr_err("%pOF: Could not map registers.\n", np);
-		goto error_free;
-	}
-
-	/* Initialize MUX map */
-	for (i = 0; i < ARRAY_SIZE(mapping); i++)
-		mapping[i] = IRQ_UNMAPPED;
-
-	parse_priority_map(pic, mapping, ARRAY_SIZE(mapping));
-
-	/*
-	 * We can have up to 12 interrupts cascading to the core controller.
-	 * These cascades can be from the combined interrupt sources or for
-	 * individual interrupt sources. The "interrupts" property only
-	 * deals with the cascaded combined interrupts. The individual
-	 * interrupts muxed to the core controller use the core controller
-	 * as their interrupt parent.
-	 */
-	for (i = 0; i < NR_COMBINERS; i++) {
-		struct irq_data *irq_data;
-		irq_hw_number_t hwirq;
-
-		irq = irq_of_parse_and_map(np, i);
-		if (irq == NO_IRQ)
-			continue;
-
-		irq_data = irq_get_irq_data(irq);
-		if (!irq_data) {
-			pr_err("%pOF: combiner-%d no irq_data for virq %d!\n",
-			       np, i, irq);
-			continue;
-		}
-
-		hwirq = irq_data->hwirq;
-
-		/*
-		 * Check that device tree provided something in the range
-		 * of the core priority interrupts (4 - 15).
-		 */
-		if (hwirq < 4 || hwirq >= NR_PRIORITY_IRQS) {
-			pr_err("%pOF: combiner-%d core irq %ld out of range!\n",
-			       np, i, hwirq);
-			continue;
-		}
-
-		/* record the mapping */
-		mapping[hwirq - 4] = i;
-
-		pr_debug("%pOF: combiner-%d cascading to hwirq %ld\n",
-			 np, i, hwirq);
-
-		cascade_data[i].pic = pic;
-		cascade_data[i].index = i;
-
-		/* mask and clear all events in combiner */
-		soc_writel(~0, &pic->regs->evtmask[i]);
-		soc_writel(~0, &pic->regs->evtclr[i]);
-
-		irq_set_chained_handler_and_data(irq, megamod_irq_cascade,
-						 &cascade_data[i]);
-	}
-
-	/* Finally, set up the MUX registers */
-	for (i = 0; i < NR_MUX_OUTPUTS; i++) {
-		if (mapping[i] != IRQ_UNMAPPED) {
-			pr_debug("%pOF: setting mux %d to priority %d\n",
-				 np, mapping[i], i + 4);
-			set_megamod_mux(pic, mapping[i], i);
-		}
-	}
-
-	return pic;
-
-error_free:
-	kfree(pic);
-
-	return NULL;
-}
-
-/*
- * Return next active event after ACK'ing it.
- * Return -1 if no events active.
- */
-static int get_exception(void)
-{
-	int i, bit;
-	u32 mask;
-
-	for (i = 0; i < NR_COMBINERS; i++) {
-		mask = soc_readl(&mm_pic->regs->mexpflag[i]);
-		if (mask) {
-			bit = __ffs(mask);
-			soc_writel(1 << bit, &mm_pic->regs->evtclr[i]);
-			return (i * 32) + bit;
-		}
-	}
-	return -1;
-}
-
-static void assert_event(unsigned int val)
-{
-	soc_writel(val, &mm_pic->regs->evtasrt);
-}
-
-void __init megamod_pic_init(void)
-{
-	struct device_node *np;
-
-	np = of_find_compatible_node(NULL, NULL, "ti,c64x+megamod-pic");
-	if (!np)
-		return;
-
-	mm_pic = init_megamod_pic(np);
-	of_node_put(np);
-
-	soc_ops.get_exception = get_exception;
-	soc_ops.assert_event = assert_event;
-
-	return;
-}