arch/arm/mm/cache-feroceon-l2.c - linux - Git at Google

 /*
  * arch/arm/mm/cache-feroceon-l2.c - Feroceon L2 cache controller support
  *
  * Copyright (C) 2008 Marvell Semiconductor
  *
  * This file is licensed under the terms of the GNU General Public
  * License version 2.  This program is licensed "as is" without any
  * warranty of any kind, whether express or implied.
  *
  * References:
  * - Unified Layer 2 Cache for Feroceon CPU Cores,
  *   Document ID MV-S104858-00, Rev. A, October 23 2007.
  */

 #include <linux/init.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/highmem.h>
 #include <linux/io.h>
 #include <asm/cacheflush.h>
 #include <asm/cp15.h>
 #include <asm/hardware/cache-feroceon-l2.h>

 #define L2_WRITETHROUGH_KIRKWOOD	BIT(4)

 /*
  * Low-level cache maintenance operations.
  *
  * As well as the regular 'clean/invalidate/flush L2 cache line by
  * MVA' instructions, the Feroceon L2 cache controller also features
  * 'clean/invalidate L2 range by MVA' operations.
  *
  * Cache range operations are initiated by writing the start and
  * end addresses to successive cp15 registers, and process every
  * cache line whose first byte address lies in the inclusive range
  * [start:end].
  *
  * The cache range operations stall the CPU pipeline until completion.
  *
  * The range operations require two successive cp15 writes, in
  * between which we don't want to be preempted.
  */

 static inline unsigned long l2_get_va(unsigned long paddr)
 {
 #ifdef CONFIG_HIGHMEM
 	/*
 	 * Because range ops can't be done on physical addresses,
 	 * we simply install a virtual mapping for it only for the
 	 * TLB lookup to occur, hence no need to flush the untouched
 	 * memory mapping afterwards (note: a cache flush may happen
 	 * in some circumstances depending on the path taken in kunmap_atomic).
 	 */
 	void *vaddr = kmap_atomic_pfn(paddr >> PAGE_SHIFT);
 	return (unsigned long)vaddr + (paddr & ~PAGE_MASK);
 #else
 	return __phys_to_virt(paddr);
 #endif
 }

 static inline void l2_put_va(unsigned long vaddr)
 {
 #ifdef CONFIG_HIGHMEM
 	kunmap_atomic((void *)vaddr);
 #endif
 }

 static inline void l2_clean_pa(unsigned long addr)
 {
 	__asm__("mcr p15, 1, %0, c15, c9, 3" : : "r" (addr));
 }

 static inline void l2_clean_pa_range(unsigned long start, unsigned long end)
 {
 	unsigned long va_start, va_end, flags;

 	/*
 	 * Make sure 'start' and 'end' reference the same page, as
 	 * L2 is PIPT and range operations only do a TLB lookup on
 	 * the start address.
 	 */
 	BUG_ON((start ^ end) >> PAGE_SHIFT);

 	va_start = l2_get_va(start);
 	va_end = va_start + (end - start);
 	raw_local_irq_save(flags);
 	__asm__("mcr p15, 1, %0, c15, c9, 4\n\t"
 		"mcr p15, 1, %1, c15, c9, 5"
 		: : "r" (va_start), "r" (va_end));
 	raw_local_irq_restore(flags);
 	l2_put_va(va_start);
 }

 static inline void l2_clean_inv_pa(unsigned long addr)
 {
 	__asm__("mcr p15, 1, %0, c15, c10, 3" : : "r" (addr));
 }

 static inline void l2_inv_pa(unsigned long addr)
 {
 	__asm__("mcr p15, 1, %0, c15, c11, 3" : : "r" (addr));
 }

 static inline void l2_inv_pa_range(unsigned long start, unsigned long end)
 {
 	unsigned long va_start, va_end, flags;

 	/*
 	 * Make sure 'start' and 'end' reference the same page, as
 	 * L2 is PIPT and range operations only do a TLB lookup on
 	 * the start address.
 	 */
 	BUG_ON((start ^ end) >> PAGE_SHIFT);

 	va_start = l2_get_va(start);
 	va_end = va_start + (end - start);
 	raw_local_irq_save(flags);
 	__asm__("mcr p15, 1, %0, c15, c11, 4\n\t"
 		"mcr p15, 1, %1, c15, c11, 5"
 		: : "r" (va_start), "r" (va_end));
 	raw_local_irq_restore(flags);
 	l2_put_va(va_start);
 }

 static inline void l2_inv_all(void)
 {
 	__asm__("mcr p15, 1, %0, c15, c11, 0" : : "r" (0));
 }

 /*
  * Linux primitives.
  *
  * Note that the end addresses passed to Linux primitives are
  * noninclusive, while the hardware cache range operations use
  * inclusive start and end addresses.
  */
 #define CACHE_LINE_SIZE		32
 #define MAX_RANGE_SIZE		1024

 static int l2_wt_override;

 static unsigned long calc_range_end(unsigned long start, unsigned long end)
 {
 	unsigned long range_end;

 	BUG_ON(start & (CACHE_LINE_SIZE - 1));
 	BUG_ON(end & (CACHE_LINE_SIZE - 1));

 	/*
 	 * Try to process all cache lines between 'start' and 'end'.
 	 */
 	range_end = end;

 	/*
 	 * Limit the number of cache lines processed at once,
 	 * since cache range operations stall the CPU pipeline
 	 * until completion.
 	 */
 	if (range_end > start + MAX_RANGE_SIZE)
 		range_end = start + MAX_RANGE_SIZE;

 	/*
 	 * Cache range operations can't straddle a page boundary.
 	 */
 	if (range_end > (start | (PAGE_SIZE - 1)) + 1)
 		range_end = (start | (PAGE_SIZE - 1)) + 1;

 	return range_end;
 }

 static void feroceon_l2_inv_range(unsigned long start, unsigned long end)
 {
 	/*
 	 * Clean and invalidate partial first cache line.
 	 */
 	if (start & (CACHE_LINE_SIZE - 1)) {
 		l2_clean_inv_pa(start & ~(CACHE_LINE_SIZE - 1));
 		start = (start | (CACHE_LINE_SIZE - 1)) + 1;
 	}

 	/*
 	 * Clean and invalidate partial last cache line.
 	 */
 	if (start < end && end & (CACHE_LINE_SIZE - 1)) {
 		l2_clean_inv_pa(end & ~(CACHE_LINE_SIZE - 1));
 		end &= ~(CACHE_LINE_SIZE - 1);
 	}

 	/*
 	 * Invalidate all full cache lines between 'start' and 'end'.
 	 */
 	while (start < end) {
 		unsigned long range_end = calc_range_end(start, end);
 		l2_inv_pa_range(start, range_end - CACHE_LINE_SIZE);
 		start = range_end;
 	}

 	dsb();
 }

 static void feroceon_l2_clean_range(unsigned long start, unsigned long end)
 {
 	/*
 	 * If L2 is forced to WT, the L2 will always be clean and we
 	 * don't need to do anything here.
 	 */
 	if (!l2_wt_override) {
 		start &= ~(CACHE_LINE_SIZE - 1);
 		end = (end + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1);
 		while (start != end) {
 			unsigned long range_end = calc_range_end(start, end);
 			l2_clean_pa_range(start, range_end - CACHE_LINE_SIZE);
 			start = range_end;
 		}
 	}

 	dsb();
 }

 static void feroceon_l2_flush_range(unsigned long start, unsigned long end)
 {
 	start &= ~(CACHE_LINE_SIZE - 1);
 	end = (end + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1);
 	while (start != end) {
 		unsigned long range_end = calc_range_end(start, end);
 		if (!l2_wt_override)
 			l2_clean_pa_range(start, range_end - CACHE_LINE_SIZE);
 		l2_inv_pa_range(start, range_end - CACHE_LINE_SIZE);
 		start = range_end;
 	}

 	dsb();
 }


 /*
  * Routines to disable and re-enable the D-cache and I-cache at run
  * time.  These are necessary because the L2 cache can only be enabled
  * or disabled while the L1 Dcache and Icache are both disabled.
  */
 static int __init flush_and_disable_dcache(void)
 {
 	u32 cr;

 	cr = get_cr();
 	if (cr & CR_C) {
 		unsigned long flags;

 		raw_local_irq_save(flags);
 		flush_cache_all();
 		set_cr(cr & ~CR_C);
 		raw_local_irq_restore(flags);
 		return 1;
 	}
 	return 0;
 }

 static void __init enable_dcache(void)
 {
 	u32 cr;

 	cr = get_cr();
 	set_cr(cr | CR_C);
 }

 static void __init __invalidate_icache(void)
 {
 	__asm__("mcr p15, 0, %0, c7, c5, 0" : : "r" (0));
 }

 static int __init invalidate_and_disable_icache(void)
 {
 	u32 cr;

 	cr = get_cr();
 	if (cr & CR_I) {
 		set_cr(cr & ~CR_I);
 		__invalidate_icache();
 		return 1;
 	}
 	return 0;
 }

 static void __init enable_icache(void)
 {
 	u32 cr;

 	cr = get_cr();
 	set_cr(cr | CR_I);
 }

 static inline u32 read_extra_features(void)
 {
 	u32 u;

 	__asm__("mrc p15, 1, %0, c15, c1, 0" : "=r" (u));

 	return u;
 }

 static inline void write_extra_features(u32 u)
 {
 	__asm__("mcr p15, 1, %0, c15, c1, 0" : : "r" (u));
 }

 static void __init disable_l2_prefetch(void)
 {
 	u32 u;

 	/*
 	 * Read the CPU Extra Features register and verify that the
 	 * Disable L2 Prefetch bit is set.
 	 */
 	u = read_extra_features();
 	if (!(u & 0x01000000)) {
 		pr_info("Feroceon L2: Disabling L2 prefetch.\n");
 		write_extra_features(u | 0x01000000);
 	}
 }

 static void __init enable_l2(void)
 {
 	u32 u;

 	u = read_extra_features();
 	if (!(u & 0x00400000)) {
 		int i, d;

 		pr_info("Feroceon L2: Enabling L2\n");

 		d = flush_and_disable_dcache();
 		i = invalidate_and_disable_icache();
 		l2_inv_all();
 		write_extra_features(u | 0x00400000);
 		if (i)
 			enable_icache();
 		if (d)
 			enable_dcache();
 	} else
 		pr_err(FW_BUG
 		       "Feroceon L2: bootloader left the L2 cache on!\n");
 }

 void __init feroceon_l2_init(int __l2_wt_override)
 {
 	l2_wt_override = __l2_wt_override;

 	disable_l2_prefetch();

 	outer_cache.inv_range = feroceon_l2_inv_range;
 	outer_cache.clean_range = feroceon_l2_clean_range;
 	outer_cache.flush_range = feroceon_l2_flush_range;

 	enable_l2();

 	pr_info("Feroceon L2: Cache support initialised%s.\n",
 			 l2_wt_override ? ", in WT override mode" : "");
 }
 #ifdef CONFIG_OF
 static const struct of_device_id feroceon_ids[] __initconst = {
 	{ .compatible = "marvell,kirkwood-cache"},
 	{ .compatible = "marvell,feroceon-cache"},
 	{}
 };

 int __init feroceon_of_init(void)
 {
 	struct device_node *node;
 	void __iomem *base;
 	bool l2_wt_override = false;

 #if defined(CONFIG_CACHE_FEROCEON_L2_WRITETHROUGH)
 	l2_wt_override = true;
 #endif

 	node = of_find_matching_node(NULL, feroceon_ids);
 	if (node && of_device_is_compatible(node, "marvell,kirkwood-cache")) {
 		base = of_iomap(node, 0);
 		if (!base)
 			return -ENOMEM;

 		if (l2_wt_override)
 			writel(readl(base) | L2_WRITETHROUGH_KIRKWOOD, base);
 		else
 			writel(readl(base) & ~L2_WRITETHROUGH_KIRKWOOD, base);
 	}

 	feroceon_l2_init(l2_wt_override);

 	return 0;
 }
 #endif
	/*
	* arch/arm/mm/cache-feroceon-l2.c - Feroceon L2 cache controller support
	*
	* Copyright (C) 2008 Marvell Semiconductor
	*
	* This file is licensed under the terms of the GNU General Public
	* License version 2. This program is licensed "as is" without any
	* warranty of any kind, whether express or implied.
	*
	* References:
	* - Unified Layer 2 Cache for Feroceon CPU Cores,
	* Document ID MV-S104858-00, Rev. A, October 23 2007.
	*/

	#include <linux/init.h>
	#include <linux/of.h>
	#include <linux/of_address.h>
	#include <linux/highmem.h>
	#include <linux/io.h>
	#include <asm/cacheflush.h>
	#include <asm/cp15.h>
	#include <asm/hardware/cache-feroceon-l2.h>

	#define L2_WRITETHROUGH_KIRKWOOD BIT(4)

	/*
	* Low-level cache maintenance operations.
	*
	* As well as the regular 'clean/invalidate/flush L2 cache line by
	* MVA' instructions, the Feroceon L2 cache controller also features
	* 'clean/invalidate L2 range by MVA' operations.
	*
	* Cache range operations are initiated by writing the start and
	* end addresses to successive cp15 registers, and process every
	* cache line whose first byte address lies in the inclusive range
	* [start:end].
	*
	* The cache range operations stall the CPU pipeline until completion.
	*
	* The range operations require two successive cp15 writes, in
	* between which we don't want to be preempted.
	*/

	static inline unsigned long l2_get_va(unsigned long paddr)
	{
	#ifdef CONFIG_HIGHMEM
	/*
	* Because range ops can't be done on physical addresses,
	* we simply install a virtual mapping for it only for the
	* TLB lookup to occur, hence no need to flush the untouched
	* memory mapping afterwards (note: a cache flush may happen
	* in some circumstances depending on the path taken in kunmap_atomic).
	*/
	void *vaddr = kmap_atomic_pfn(paddr >> PAGE_SHIFT);
	return (unsigned long)vaddr + (paddr & ~PAGE_MASK);
	#else
	return __phys_to_virt(paddr);
	#endif
	}

	static inline void l2_put_va(unsigned long vaddr)
	{
	#ifdef CONFIG_HIGHMEM
	kunmap_atomic((void *)vaddr);
	#endif
	}

	static inline void l2_clean_pa(unsigned long addr)
	{
	__asm__("mcr p15, 1, %0, c15, c9, 3" : : "r" (addr));
	}

	static inline void l2_clean_pa_range(unsigned long start, unsigned long end)
	{
	unsigned long va_start, va_end, flags;

	/*
	* Make sure 'start' and 'end' reference the same page, as
	* L2 is PIPT and range operations only do a TLB lookup on
	* the start address.
	*/
	BUG_ON((start ^ end) >> PAGE_SHIFT);

	va_start = l2_get_va(start);
	va_end = va_start + (end - start);
	raw_local_irq_save(flags);
	__asm__("mcr p15, 1, %0, c15, c9, 4\n\t"
	"mcr p15, 1, %1, c15, c9, 5"
	: : "r" (va_start), "r" (va_end));
	raw_local_irq_restore(flags);
	l2_put_va(va_start);
	}

	static inline void l2_clean_inv_pa(unsigned long addr)
	{
	__asm__("mcr p15, 1, %0, c15, c10, 3" : : "r" (addr));
	}

	static inline void l2_inv_pa(unsigned long addr)
	{
	__asm__("mcr p15, 1, %0, c15, c11, 3" : : "r" (addr));
	}

	static inline void l2_inv_pa_range(unsigned long start, unsigned long end)
	{
	unsigned long va_start, va_end, flags;

	/*
	* Make sure 'start' and 'end' reference the same page, as
	* L2 is PIPT and range operations only do a TLB lookup on
	* the start address.
	*/
	BUG_ON((start ^ end) >> PAGE_SHIFT);

	va_start = l2_get_va(start);
	va_end = va_start + (end - start);
	raw_local_irq_save(flags);
	__asm__("mcr p15, 1, %0, c15, c11, 4\n\t"
	"mcr p15, 1, %1, c15, c11, 5"
	: : "r" (va_start), "r" (va_end));
	raw_local_irq_restore(flags);
	l2_put_va(va_start);
	}

	static inline void l2_inv_all(void)
	{
	__asm__("mcr p15, 1, %0, c15, c11, 0" : : "r" (0));
	}

	/*
	* Linux primitives.
	*
	* Note that the end addresses passed to Linux primitives are
	* noninclusive, while the hardware cache range operations use
	* inclusive start and end addresses.
	*/
	#define CACHE_LINE_SIZE 32
	#define MAX_RANGE_SIZE 1024

	static int l2_wt_override;

	static unsigned long calc_range_end(unsigned long start, unsigned long end)
	{
	unsigned long range_end;

	BUG_ON(start & (CACHE_LINE_SIZE - 1));
	BUG_ON(end & (CACHE_LINE_SIZE - 1));

	/*
	* Try to process all cache lines between 'start' and 'end'.
	*/
	range_end = end;

	/*
	* Limit the number of cache lines processed at once,
	* since cache range operations stall the CPU pipeline
	* until completion.
	*/
	if (range_end > start + MAX_RANGE_SIZE)
	range_end = start + MAX_RANGE_SIZE;

	/*
	* Cache range operations can't straddle a page boundary.
	*/
	if (range_end > (start \| (PAGE_SIZE - 1)) + 1)
	range_end = (start \| (PAGE_SIZE - 1)) + 1;

	return range_end;
	}

	static void feroceon_l2_inv_range(unsigned long start, unsigned long end)
	{
	/*
	* Clean and invalidate partial first cache line.
	*/
	if (start & (CACHE_LINE_SIZE - 1)) {
	l2_clean_inv_pa(start & ~(CACHE_LINE_SIZE - 1));
	start = (start \| (CACHE_LINE_SIZE - 1)) + 1;
	}

	/*
	* Clean and invalidate partial last cache line.
	*/
	if (start < end && end & (CACHE_LINE_SIZE - 1)) {
	l2_clean_inv_pa(end & ~(CACHE_LINE_SIZE - 1));
	end &= ~(CACHE_LINE_SIZE - 1);
	}

	/*
	* Invalidate all full cache lines between 'start' and 'end'.
	*/
	while (start < end) {
	unsigned long range_end = calc_range_end(start, end);
	l2_inv_pa_range(start, range_end - CACHE_LINE_SIZE);
	start = range_end;
	}

	dsb();
	}

	static void feroceon_l2_clean_range(unsigned long start, unsigned long end)
	{
	/*
	* If L2 is forced to WT, the L2 will always be clean and we
	* don't need to do anything here.
	*/
	if (!l2_wt_override) {
	start &= ~(CACHE_LINE_SIZE - 1);
	end = (end + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1);
	while (start != end) {
	unsigned long range_end = calc_range_end(start, end);
	l2_clean_pa_range(start, range_end - CACHE_LINE_SIZE);
	start = range_end;
	}
	}

	dsb();
	}

	static void feroceon_l2_flush_range(unsigned long start, unsigned long end)
	{
	start &= ~(CACHE_LINE_SIZE - 1);
	end = (end + CACHE_LINE_SIZE - 1) & ~(CACHE_LINE_SIZE - 1);
	while (start != end) {
	unsigned long range_end = calc_range_end(start, end);
	if (!l2_wt_override)
	l2_clean_pa_range(start, range_end - CACHE_LINE_SIZE);
	l2_inv_pa_range(start, range_end - CACHE_LINE_SIZE);
	start = range_end;
	}

	dsb();
	}


	/*
	* Routines to disable and re-enable the D-cache and I-cache at run
	* time. These are necessary because the L2 cache can only be enabled
	* or disabled while the L1 Dcache and Icache are both disabled.
	*/
	static int __init flush_and_disable_dcache(void)
	{
	u32 cr;

	cr = get_cr();
	if (cr & CR_C) {
	unsigned long flags;

	raw_local_irq_save(flags);
	flush_cache_all();
	set_cr(cr & ~CR_C);
	raw_local_irq_restore(flags);
	return 1;
	}
	return 0;
	}

	static void __init enable_dcache(void)
	{
	u32 cr;

	cr = get_cr();
	set_cr(cr \| CR_C);
	}

	static void __init __invalidate_icache(void)
	{
	__asm__("mcr p15, 0, %0, c7, c5, 0" : : "r" (0));
	}

	static int __init invalidate_and_disable_icache(void)
	{
	u32 cr;

	cr = get_cr();
	if (cr & CR_I) {
	set_cr(cr & ~CR_I);
	__invalidate_icache();
	return 1;
	}
	return 0;
	}

	static void __init enable_icache(void)
	{
	u32 cr;

	cr = get_cr();
	set_cr(cr \| CR_I);
	}

	static inline u32 read_extra_features(void)
	{
	u32 u;

	__asm__("mrc p15, 1, %0, c15, c1, 0" : "=r" (u));

	return u;
	}

	static inline void write_extra_features(u32 u)
	{
	__asm__("mcr p15, 1, %0, c15, c1, 0" : : "r" (u));
	}

	static void __init disable_l2_prefetch(void)
	{
	u32 u;

	/*
	* Read the CPU Extra Features register and verify that the
	* Disable L2 Prefetch bit is set.
	*/
	u = read_extra_features();
	if (!(u & 0x01000000)) {
	pr_info("Feroceon L2: Disabling L2 prefetch.\n");
	write_extra_features(u \| 0x01000000);
	}
	}

	static void __init enable_l2(void)
	{
	u32 u;

	u = read_extra_features();
	if (!(u & 0x00400000)) {
	int i, d;

	pr_info("Feroceon L2: Enabling L2\n");

	d = flush_and_disable_dcache();
	i = invalidate_and_disable_icache();
	l2_inv_all();
	write_extra_features(u \| 0x00400000);
	if (i)
	enable_icache();
	if (d)
	enable_dcache();
	} else
	pr_err(FW_BUG
	"Feroceon L2: bootloader left the L2 cache on!\n");
	}

	void __init feroceon_l2_init(int __l2_wt_override)
	{
	l2_wt_override = __l2_wt_override;

	disable_l2_prefetch();

	outer_cache.inv_range = feroceon_l2_inv_range;
	outer_cache.clean_range = feroceon_l2_clean_range;
	outer_cache.flush_range = feroceon_l2_flush_range;

	enable_l2();

	pr_info("Feroceon L2: Cache support initialised%s.\n",
	l2_wt_override ? ", in WT override mode" : "");
	}
	#ifdef CONFIG_OF
	static const struct of_device_id feroceon_ids[] __initconst = {
	{ .compatible = "marvell,kirkwood-cache"},
	{ .compatible = "marvell,feroceon-cache"},
	{}
	};

	int __init feroceon_of_init(void)
	{
	struct device_node *node;
	void __iomem *base;
	bool l2_wt_override = false;

	#if defined(CONFIG_CACHE_FEROCEON_L2_WRITETHROUGH)
	l2_wt_override = true;
	#endif

	node = of_find_matching_node(NULL, feroceon_ids);
	if (node && of_device_is_compatible(node, "marvell,kirkwood-cache")) {
	base = of_iomap(node, 0);
	if (!base)
	return -ENOMEM;

	if (l2_wt_override)
	writel(readl(base) \| L2_WRITETHROUGH_KIRKWOOD, base);
	else
	writel(readl(base) & ~L2_WRITETHROUGH_KIRKWOOD, base);
	}

	feroceon_l2_init(l2_wt_override);

	return 0;
	}
	#endif