1 files changed, 396 insertions, 0 deletions
diff --git a/kernel/arch/arm/mm/cache-feroceon-l2.c b/kernel/arch/arm/mm/cache-feroceon-l2.c
new file mode 100644
index 000000000..097181e08
--- /dev/null
+++ b/kernel/arch/arm/mm/cache-feroceon-l2.c
@@ -0,0 +1,396 @@
+/*
+ * 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;
+	struct resource res;
+
+#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")) {
+		if (of_address_to_resource(node, 0, &res))
+			return -ENODEV;
+
+		base = ioremap(res.start, resource_size(&res));
+		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