ARC: Support for single cycle Close Coupled Mem (CCM)

* Includes mapping of CCMs in address space
* Annotations to move arbitrary code/data into CCM
* Moving some of the critical code/data into CCM
* Runtime detection/reporting

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

3 files changed, 75 insertions, 3 deletions

diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S
index f8efade15368..3f628ca9b71a 100644
--- a/arch/arc/kernel/entry.S
+++ b/arch/arc/kernel/entry.S
@@ -149,7 +149,7 @@ VECTOR   reserved                ; Reserved Exceptions
 
 ;##################### Scratch Mem for IRQ stack switching #############
 
-        .section .data          ; NOT .global
+ARCFP_DATA int1_saved_reg
         .align 32
         .type   int1_saved_reg, @object
         .size   int1_saved_reg, 4
@@ -159,7 +159,7 @@ int1_saved_reg:
 /* Each Interrupt level needs it's own scratch */
 #ifdef CONFIG_ARC_COMPACT_IRQ_LEVELS
 
-        .section .data          ; NOT .global
+ARCFP_DATA int2_saved_reg
         .type   int2_saved_reg, @object
         .size   int2_saved_reg, 4
 int2_saved_reg:
diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index e25538e29fe7..6cc361c6751a 100644
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -64,6 +64,33 @@ void __init read_arc_build_cfg_regs(void)
         cpu->extn.ext_arith = read_aux_reg(ARC_REG_EXTARITH_BCR);
         cpu->extn.crc = read_aux_reg(ARC_REG_CRC_BCR);
 
+        /* Note that we read the CCM BCRs independent of kernel config
+         * This is to catch the cases where user doesn't know that
+         * CCMs are present in hardware build
+         */
+        {
+                struct bcr_iccm iccm;
+                struct bcr_dccm dccm;
+                struct bcr_dccm_base dccm_base;
+                unsigned int bcr_32bit_val;
+
+                bcr_32bit_val = read_aux_reg(ARC_REG_ICCM_BCR);
+                if (bcr_32bit_val) {
+                        iccm = *((struct bcr_iccm *)&bcr_32bit_val);
+                        cpu->iccm.base_addr = iccm.base << 16;
+                        cpu->iccm.sz = 0x2000 << (iccm.sz - 1);
+                }
+
+                bcr_32bit_val = read_aux_reg(ARC_REG_DCCM_BCR);
+                if (bcr_32bit_val) {
+                        dccm = *((struct bcr_dccm *)&bcr_32bit_val);
+                        cpu->dccm.sz = 0x800 << (dccm.sz);
+
+                        READ_BCR(ARC_REG_DCCMBASE_BCR, dccm_base);
+                        cpu->dccm.base_addr = dccm_base.addr << 8;
+                }
+        }
+
         READ_BCR(ARC_REG_XY_MEM_BCR, cpu->extn_xymem);
 
         read_decode_mmu_bcr();
@@ -211,6 +238,30 @@ char *arc_extn_mumbojumbo(int cpu_id, char *buf, int len)
         return buf;
 }
 
+void __init arc_chk_ccms(void)
+{
+#if defined(CONFIG_ARC_HAS_DCCM) || defined(CONFIG_ARC_HAS_ICCM)
+        struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
+
+#ifdef CONFIG_ARC_HAS_DCCM
+        /*
+         * DCCM can be arbit placed in hardware.
+         * Make sure it's placement/sz matches what Linux is built with
+         */
+        if ((unsigned int)__arc_dccm_base != cpu->dccm.base_addr)
+                panic("Linux built with incorrect DCCM Base address\n");
+
+        if (CONFIG_ARC_DCCM_SZ != cpu->dccm.sz)
+                panic("Linux built with incorrect DCCM Size\n");
+#endif
+
+#ifdef CONFIG_ARC_HAS_ICCM
+        if (CONFIG_ARC_ICCM_SZ != cpu->iccm.sz)
+                panic("Linux built with incorrect ICCM Size\n");
+#endif
+#endif
+}
+
 /*
  * Ensure that FP hardware and kernel config match
  * -If hardware contains DPFP, kernel needs to save/restore FPU state
@@ -255,7 +306,7 @@ void __init setup_processor(void)
 
         arc_mmu_init();
         arc_cache_init();
-
+        arc_chk_ccms();
 
         printk(arc_extn_mumbojumbo(cpu_id, str, sizeof(str)));
 
diff --git a/arch/arc/kernel/vmlinux.lds.S b/arch/arc/kernel/vmlinux.lds.S
index 303ea01c85c8..8d3b0d447498 100644
--- a/arch/arc/kernel/vmlinux.lds.S
+++ b/arch/arc/kernel/vmlinux.lds.S
@@ -23,6 +23,12 @@ jiffies = jiffies_64;
 
 SECTIONS
 {
+        /*
+         * ICCM starts at 0x8000_0000. So if kernel is relocated to some other
+         * address, make sure peripheral at 0x8z doesn't clash with ICCM
+         * Essentially vector is also in ICCM.
+         */
+
         . = CONFIG_LINUX_LINK_BASE;
 
         _int_vec_base_lds = .;
@@ -31,6 +37,13 @@ SECTIONS
                 . = ALIGN(PAGE_SIZE);
         }
 
+#ifdef CONFIG_ARC_HAS_ICCM
+        .text.arcfp : {
+                *(.text.arcfp)
+                . = ALIGN(CONFIG_ARC_ICCM_SZ * 1024);
+        }
+#endif
+
         /*
          * The reason for having a seperate subsection .init.ramfs is to
          * prevent objump from including it in kernel dumps
@@ -134,4 +147,12 @@ SECTIONS
         .debug_loc 0 : { *(.debug_loc) }
         .debug_macinfo 0 : { *(.debug_macinfo) }
 
+#ifdef CONFIG_ARC_HAS_DCCM
+        . = CONFIG_ARC_DCCM_BASE;
+        __arc_dccm_base = .;
+        .data.arcfp : {
+                *(.data.arcfp)
+        }
+        . = ALIGN(CONFIG_ARC_DCCM_SZ * 1024);
+#endif
 }