[reggen] Disallow internal shadow registers from hardware write.
- When the shadow registers were first conceived it was mostly
treated as a software RW register, we did not give a ton
of thought as to how HW writes should behave.
- Currently, HW writes follow the same rules as softawre writes,
ie, they need to be written twice before the value takes effect.
This seems very odd and may not be the ideal behavior.
- Instead of quickly hacking the shadow regs to a different behavior,
for now disable this combination and see if there is a real usecase
for it.
Signed-off-by: Timothy Chen <timothytim@google.com>
diff --git a/util/reggen/field.py b/util/reggen/field.py
index 5608804..2f9d0b9 100644
--- a/util/reggen/field.py
+++ b/util/reggen/field.py
@@ -71,6 +71,8 @@
reg_resval: Optional[int],
reg_width: int,
params: ReggenParams,
+ hwext: bool,
+ shadowed: bool,
raw: object) -> 'Field':
where = 'field {} of {} register'.format(field_idx, reg_name)
rd = check_keys(raw, where,
@@ -108,6 +110,11 @@
else:
hwaccess = default_hwaccess
+ # Currently internal shadow registers do not support hw write type
+ if not hwext and shadowed and hwaccess.allows_write():
+ raise ValueError('Internal Shadow registers do not currently support '
+ 'hardware write')
+
bits = Bits.from_raw(where, reg_width, params, rd['bits'])
raw_resval = rd.get('resval')
diff --git a/util/reggen/register.py b/util/reggen/register.py
index 537ac8c..5c071b5 100644
--- a/util/reggen/register.py
+++ b/util/reggen/register.py
@@ -267,6 +267,8 @@
resval,
reg_width,
params,
+ hwext,
+ shadowed,
rf)
for idx, rf in enumerate(raw_fields)]
