MIPS: L2 cache support

This patch adds support for initialising & maintaining L2 caches on MIPS
systems. The L2 cache configuration may be advertised through either
coprocessor 0 or the MIPS Coherence Manager depending upon the system,
and support for both is included.

If the L2 can be bypassed then we bypass it early in boot & initialise
the L1 caches first, such that we can start making use of the L1
instruction cache as early as possible. Otherwise we initialise the L2
first such that the L1s have no opportunity to generate access to the
uninitialised L2.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>

1 files changed, 38 insertions, 0 deletions

diff --git a/arch/mips/include/asm/cm.h b/arch/mips/include/asm/cm.h
index 0261733826..62ecef20fc 100644
--- a/arch/mips/include/asm/cm.h
+++ b/arch/mips/include/asm/cm.h
@@ -12,8 +12,46 @@
 #define GCR_BASE			0x0008
 #define GCR_BASE_UPPER			0x000c
 #define GCR_REV				0x0030
+#define GCR_L2_CONFIG			0x0130
+#define GCR_L2_TAG_ADDR			0x0600
+#define GCR_L2_TAG_ADDR_UPPER		0x0604
+#define GCR_L2_TAG_STATE		0x0608
+#define GCR_L2_TAG_STATE_UPPER		0x060c
+#define GCR_L2_DATA			0x0610
+#define GCR_L2_DATA_UPPER		0x0614
 
 /* GCR_REV CM versions */
 #define GCR_REV_CM3			0x0800
 
+/* GCR_L2_CONFIG fields */
+#define GCR_L2_CONFIG_ASSOC_SHIFT	0
+#define GCR_L2_CONFIG_ASSOC_BITS	8
+#define GCR_L2_CONFIG_LINESZ_SHIFT	8
+#define GCR_L2_CONFIG_LINESZ_BITS	4
+#define GCR_L2_CONFIG_SETSZ_SHIFT	12
+#define GCR_L2_CONFIG_SETSZ_BITS	4
+#define GCR_L2_CONFIG_BYPASS		(1 << 20)
+
+#ifndef __ASSEMBLY__
+
+#include <asm/io.h>
+
+static inline void *mips_cm_base(void)
+{
+	return (void *)CKSEG1ADDR(CONFIG_MIPS_CM_BASE);
+}
+
+static inline unsigned long mips_cm_l2_line_size(void)
+{
+	unsigned long l2conf, line_sz;
+
+	l2conf = __raw_readl(mips_cm_base() + GCR_L2_CONFIG);
+
+	line_sz = l2conf >> GCR_L2_CONFIG_LINESZ_SHIFT;
+	line_sz &= GENMASK(GCR_L2_CONFIG_LINESZ_BITS - 1, 0);
+	return line_sz ? (2 << line_sz) : 0;
+}
+
+#endif /* !__ASSEMBLY__ */
+
 #endif /* __MIPS_ASM_CM_H__ */