[PATCH v2 1/3] MIPS: Add arch CDMM definitions and probing

[James Hogan]

Add architectural definitions and probing for the MIPS Common Device
Memory Map (CDMM) region. When supported and enabled at a particular
physical address, this region allows some number of per-CPU devices to
be discovered and controlled via MMIO.

A bit exists in Config3 to determine whether the feature is present, and
a CDMMBase CP0 register allows the region to be enabled at a particular
physical address.

Signed-off-by: James Hogan <james.hogan@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
---
Changes in v2:
- Fix typo in definition of MIPS_CPU_CDMM, s/0ll/ull (Maciej).
---
 arch/mips/include/asm/cpu-features.h |  4 ++++
 arch/mips/include/asm/cpu.h          |  1 +
 arch/mips/include/asm/mipsregs.h     | 11 +++++++++++
 arch/mips/kernel/cpu-probe.c         |  2 ++
 4 files changed, 18 insertions(+)

diff --git a/arch/mips/include/asm/cpu-features.h b/arch/mips/include/asm/cpu-features.h
index 2897cfafcaf0..83e9db058a72 100644
--- a/arch/mips/include/asm/cpu-features.h
+++ b/arch/mips/include/asm/cpu-features.h
@@ -348,4 +348,8 @@
 # define cpu_has_fre		(cpu_data[0].options & MIPS_CPU_FRE)
 #endif
 
+#ifndef cpu_has_cdmm
+# define cpu_has_cdmm		(cpu_data[0].options & MIPS_CPU_CDMM)
+#endif
+
 #endif /* __ASM_CPU_FEATURES_H */
diff --git a/arch/mips/include/asm/cpu.h b/arch/mips/include/asm/cpu.h
index 33866fce4d63..722c51c9650a 100644
--- a/arch/mips/include/asm/cpu.h
+++ b/arch/mips/include/asm/cpu.h
@@ -370,6 +370,7 @@ enum cpu_type_enum {
 #define MIPS_CPU_RIXIEX		0x200000000ull /* CPU has unique exception codes for {Read, Execute}-Inhibit exceptions */
 #define MIPS_CPU_MAAR		0x400000000ull /* MAAR(I) registers are present */
 #define MIPS_CPU_FRE		0x800000000ull /* FRE & UFE bits implemented */
+#define MIPS_CPU_CDMM		0x1000000000ull /* CPU has Common Device Memory Map */
 
 /*
  * CPU ASE encodings
diff --git a/arch/mips/include/asm/mipsregs.h b/arch/mips/include/asm/mipsregs.h
index 5e4aef304b02..2969ceaecfd3 100644
--- a/arch/mips/include/asm/mipsregs.h
+++ b/arch/mips/include/asm/mipsregs.h
@@ -750,6 +750,14 @@
 #define MIPS_PWCTL_PSN_SHIFT	0
 #define MIPS_PWCTL_PSN_MASK	0x0000003f
 
+/* CDMMBase register bit definitions */
+#define MIPS_CDMMBASE_SIZE_SHIFT 0
+#define MIPS_CDMMBASE_SIZE	(_ULCAST_(511) << MIPS_CDMMBASE_SIZE_SHIFT)
+#define MIPS_CDMMBASE_CI	(_ULCAST_(1) << 9)
+#define MIPS_CDMMBASE_EN	(_ULCAST_(1) << 10)
+#define MIPS_CDMMBASE_ADDR_SHIFT 11
+#define MIPS_CDMMBASE_ADDR_START 15
+
 #ifndef __ASSEMBLY__
 
 /*
@@ -1279,6 +1287,9 @@ do {									\
 #define read_c0_ebase()		__read_32bit_c0_register($15, 1)
 #define write_c0_ebase(val)	__write_32bit_c0_register($15, 1, val)
 
+#define read_c0_cdmmbase()	__read_ulong_c0_register($15, 2)
+#define write_c0_cdmmbase(val)	__write_ulong_c0_register($15, 2, val)
+
 /* MIPSR3 */
 #define read_c0_segctl0()	__read_32bit_c0_register($5, 2)
 #define write_c0_segctl0(val)	__write_32bit_c0_register($5, 2, val)
diff --git a/arch/mips/kernel/cpu-probe.c b/arch/mips/kernel/cpu-probe.c
index 5342674842f5..2eabcc023ed4 100644
--- a/arch/mips/kernel/cpu-probe.c
+++ b/arch/mips/kernel/cpu-probe.c
@@ -426,6 +426,8 @@ static inline unsigned int decode_config3(struct cpuinfo_mips *c)
 	/* Only tested on 32-bit cores */
 	if ((config3 & MIPS_CONF3_PW) && config_enabled(CONFIG_32BIT))
 		c->options |= MIPS_CPU_HTW;
+	if (config3 & MIPS_CONF3_CDMM)
+		c->options |= MIPS_CPU_CDMM;
 
 	return config3 & MIPS_CONF_M;
 }
-- 
2.0.5

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