nios2: Add CDX support

Add support for the CDX Code Density Extensions present in
Nios II R2 . This introduces new 16bit instruction set to
improve code density while retaining support for the 32bit
Nios II R2 instructions.

Signed-off-by: Marek Vasut <marex@denx.de>
Cc: Ley Foon Tan <lftan@altera.com>

4 files changed, 19 insertions, 2 deletions

diff --git a/arch/nios2/Makefile b/arch/nios2/Makefile
index 74109c01eaea..8673a79dca9c 100644
--- a/arch/nios2/Makefile
+++ b/arch/nios2/Makefile
@@ -30,6 +30,7 @@ KBUILD_CFLAGS += $(if $(CONFIG_NIOS2_HW_MUL_SUPPORT),-mhw-mul,-mno-hw-mul)
 KBUILD_CFLAGS += $(if $(CONFIG_NIOS2_HW_MULX_SUPPORT),-mhw-mulx,-mno-hw-mulx)
 KBUILD_CFLAGS += $(if $(CONFIG_NIOS2_HW_DIV_SUPPORT),-mhw-div,-mno-hw-div)
 KBUILD_CFLAGS += $(if $(CONFIG_NIOS2_BMX_SUPPORT),-mbmx,-mno-bmx)
+KBUILD_CFLAGS += $(if $(CONFIG_NIOS2_CDX_SUPPORT),-mcdx,-mno-cdx)
 KBUILD_CFLAGS += $(if $(CONFIG_NIOS2_FPU_SUPPORT),-mcustom-fpu-cfg=60-1,)
 
 KBUILD_CFLAGS += -fno-optimize-sibling-calls
diff --git a/arch/nios2/include/asm/cpuinfo.h b/arch/nios2/include/asm/cpuinfo.h
index 79d376435d7d..dbdaf96f28d4 100644
--- a/arch/nios2/include/asm/cpuinfo.h
+++ b/arch/nios2/include/asm/cpuinfo.h
@@ -30,6 +30,7 @@ struct cpuinfo {
         bool has_mul;
         bool has_mulx;
         bool has_bmx;
+        bool has_cdx;
 
         /* CPU caches */
         u32 icache_line_size;
diff --git a/arch/nios2/kernel/cpuinfo.c b/arch/nios2/kernel/cpuinfo.c
index 4c84fec34882..93207718bb22 100644
--- a/arch/nios2/kernel/cpuinfo.c
+++ b/arch/nios2/kernel/cpuinfo.c
@@ -68,6 +68,7 @@ void __init setup_cpuinfo(void)
         cpuinfo.has_mul = of_property_read_bool(cpu, "altr,has-mul");
         cpuinfo.has_mulx = of_property_read_bool(cpu, "altr,has-mulx");
         cpuinfo.has_bmx = of_property_read_bool(cpu, "altr,has-bmx");
+        cpuinfo.has_cdx = of_property_read_bool(cpu, "altr,has-cdx");
         cpuinfo.mmu = of_property_read_bool(cpu, "altr,has-mmu");
 
         if (IS_ENABLED(CONFIG_NIOS2_HW_DIV_SUPPORT) && !cpuinfo.has_div)
@@ -82,6 +83,9 @@ void __init setup_cpuinfo(void)
         if (IS_ENABLED(CONFIG_NIOS2_BMX_SUPPORT) && !cpuinfo.has_bmx)
                 err_cpu("BMX");
 
+        if (IS_ENABLED(CONFIG_NIOS2_CDX_SUPPORT) && !cpuinfo.has_cdx)
+                err_cpu("CDX");
+
         cpuinfo.tlb_num_ways = fcpu(cpu, "altr,tlb-num-ways");
         if (!cpuinfo.tlb_num_ways)
                 panic("altr,tlb-num-ways can't be 0. Please check your hardware "
@@ -148,11 +152,13 @@ static int show_cpuinfo(struct seq_file *m, void *v)
                    " MUL:\t\t%s\n"
                    " MULX:\t\t%s\n"
                    " DIV:\t\t%s\n"
-                   " BMX:\t\t%s\n",
+                   " BMX:\t\t%s\n"
+                   " CDX:\t\t%s\n",
                    cpuinfo.has_mul ? "yes" : "no",
                    cpuinfo.has_mulx ? "yes" : "no",
                    cpuinfo.has_div ? "yes" : "no",
-                   cpuinfo.has_bmx ? "yes" : "no");
+                   cpuinfo.has_bmx ? "yes" : "no",
+                   cpuinfo.has_cdx ? "yes" : "no");
 
         seq_printf(m,
                    "Icache:\t\t%ukB, line length: %u\n",
diff --git a/arch/nios2/platform/Kconfig.platform b/arch/nios2/platform/Kconfig.platform
index b6a8bfd59491..74c1aaf588b8 100644
--- a/arch/nios2/platform/Kconfig.platform
+++ b/arch/nios2/platform/Kconfig.platform
@@ -90,6 +90,15 @@ config NIOS2_BMX_SUPPORT
           the BMX Bit Manipulation Extension instructions. Enables
           the -mbmx compiler flag.
 
+config NIOS2_CDX_SUPPORT
+        bool "Enable CDX instructions"
+        depends on NIOS2_ARCH_REVISION = 2
+        default n
+        help
+          Set to true if you configured the Nios II R2 to include
+          the CDX Bit Manipulation Extension instructions. Enables
+          the -mcdx compiler flag.
+
 config NIOS2_FPU_SUPPORT
         bool "Custom floating point instr support"
         default n