[incubator-nuttx] branch master updated: arch/arm/samv7/sam_progmem: insert DMB instruction into data write loop

[xi...@apache.org]

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xiaoxiang pushed a commit to branch master
in repository https://gitbox.apache.org/repos/asf/incubator-nuttx.git


The following commit(s) were added to refs/heads/master by this push:
     new e545c44  arch/arm/samv7/sam_progmem: insert DMB instruction into data write loop
e545c44 is described below

commit e545c440f4a97185ded366479a64767f39b4fd7f
Author: Petro Karashchenko <pe...@gmail.com>
AuthorDate: Fri Feb 4 19:42:13 2022 +0200

    arch/arm/samv7/sam_progmem: insert DMB instruction into data write loop
    
    This change fix the regression that was introduced with
    https://github.com/apache/incubator-nuttx/pull/4904
    
    In case if D-Cache in configured in Write-Through mode there is
    Cortex-M7 erata 1313001 that describes a situation when linefill
    buffer or cache contains stale data. Even if progmem write loop
    does not fully matches the description there is a possibility
    to program stale data if there is no DMB instruction after each
    write operation to progmem latch buffer.
    
    Signed-off-by: Petro Karashchenko <pe...@gmail.com>
---
 arch/arm/src/samv7/sam_progmem.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/arch/arm/src/samv7/sam_progmem.c b/arch/arm/src/samv7/sam_progmem.c
index ed17fc3..02600a6 100644
--- a/arch/arm/src/samv7/sam_progmem.c
+++ b/arch/arm/src/samv7/sam_progmem.c
@@ -582,6 +582,10 @@ ssize_t up_progmem_write(size_t address, const void *buffer, size_t buflen)
       for (i = 0; i < SAMV7_PAGE_WORDS; i++)
         {
           *dest++ = *src++;
+
+#ifdef CONFIG_ARMV7M_DCACHE_WRITETHROUGH
+          ARM_DMB();
+#endif
         }
 
       /* Flush the data cache to memory */