treewide: Alias narrow SPM address space to uncached region

pulp-platform · Jan 10, 2024 · af41bde · af41bde
1 parent 9e902fc
commit af41bde
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Showing 5 changed files with 18 additions and 2 deletions.
diff --git a/target/sim/cfg/full.hjson b/target/sim/cfg/full.hjson
@@ -356,6 +356,8 @@
     spm_narrow: {
       address: 1879048192, // 0x7000_0000
       length: 524288, // 512 kiB 0x8_0000
+      # An uncached alias address space of the same length
+      uncached_alias: 1879572480, // 0x7008_0000
     },
     spm_wide: {
       address: 1895825408, // 0x7100_0000

diff --git a/target/sim/cfg/single-cluster.hjson b/target/sim/cfg/single-cluster.hjson
@@ -356,6 +356,8 @@
     spm_narrow: {
       address: 1879048192, // 0x7000_0000
       length: 524288, // 512 kiB 0x8_0000
+      # An uncached alias address space of the same length
+      uncached_alias: 1879572480, // 0x7008_0000
     },
     spm_wide: {
       address: 1895825408, // 0x7100_0000

diff --git a/target/sim/sw/host/runtime/host.c b/target/sim/sw/host/runtime/host.c
@@ -67,7 +67,8 @@ volatile uint64_t* const clint_mtimecmp0_ptr =
 // Globals
 //===============================================================
 
-volatile comm_buffer_t comm_buffer __attribute__((aligned(8)));
+comm_buffer_t comm_buffer __attribute__((aligned(8)))
+__attribute__((section(".nc_spm")));
 
 //===============================================================
 // Initialization

diff --git a/target/sim/sw/host/runtime/host.ld b/target/sim/sw/host/runtime/host.ld
@@ -7,6 +7,7 @@ ENTRY(_start)
 MEMORY
 {
     DRAM (rwxa) : ORIGIN = 0x80000000, LENGTH = 0x80000000
+    NC_SPM (rwxa) : ORIGIN = 0x70080000, LENGTH = 0x80000
 }
 
 SECTIONS
@@ -50,6 +51,12 @@ SECTIONS
     __wide_spm_end = . ;
   } > DRAM
 
+  .nc_spm :
+  {
+    *(.nc_spm)
+    . = ALIGN(8);
+  } > NC_SPM
+
   __end = .;
 
   .devicebin : { *(.devicebin) } > DRAM

diff --git a/util/occamygen/occamygen.py b/util/occamygen/occamygen.py
@@ -261,10 +261,14 @@ def main():
         occamy.cfg["pcie"]["address_mm"]).attach_to(am_soc_narrow_xbar)
 
     # Connect narrow SPM to Narrow AXI
+    bases = []
+    bases.append(occamy.cfg["spm_narrow"]["address"])
+    if "uncached_alias" in occamy.cfg["spm_narrow"]:
+        bases.append(occamy.cfg["spm_narrow"]["uncached_alias"])
     am_spm_narrow = am.new_leaf(
         "spm_narrow",
         occamy.cfg["spm_narrow"]["length"],
-        occamy.cfg["spm_narrow"]["address"]).attach_to(am_soc_narrow_xbar)
+        *bases).attach_to(am_soc_narrow_xbar)
 
     # Connect wide SPM to Wide AXI
     am_spm_wide = am.new_leaf(