Blackfin: document anomaly 05000234 workaround

Note the reason for using CHIPD over DSPID.

Signed-off-by: Robin Getz <robin.getz@analog.com>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

diff --git a/arch/blackfin/include/asm/processor.h b/arch/blackfin/include/asm/processor.h
index 0eece23b41c7c1ddaeb2f04908c20b5c9f16cd0f..3040415523b2120a338321beddb66b2cfdc8f3e1 100644 (file)
--- a/arch/blackfin/include/asm/processor.h
+++ b/arch/blackfin/include/asm/processor.h
@@ -131,8 +131,8 @@ unsigned long get_wchan(struct task_struct *p);
 /* Get the Silicon Revision of the chip */
 static inline uint32_t __pure bfin_revid(void)
 {
-       /* stored in the upper 4 bits */
-       uint32_t revid = bfin_read_CHIPID() >> 28;
+       /* Always use CHIPID, to work around ANOMALY_05000234 */
+       uint32_t revid = (bfin_read_CHIPID() & CHIPID_VERSION) >> 28;
 
 #ifdef CONFIG_BF52x
        /* ANOMALY_05000357