On Wed, Jan 08, 2025 at 09:47:11PM +0800, Luo Jie wrote:
The BM (Buffer Management) config controls the pause frame generated
on the PPE port. There are maximum 15 BM ports and 4 groups supported,
all BM ports are assigned to group 0 by default. The number of hardware
buffers configured for the port influence the threshold of the flow
control for that port.
Signed-off-by: Luo Jie <quic_luoj@xxxxxxxxxxx>
...
diff --git a/drivers/net/ethernet/qualcomm/ppe/ppe_config.c b/drivers/net/ethernet/qualcomm/ppe/ppe_config.c
...
+/* The buffer configurations per PPE port. There are 15 BM ports and
+ * 4 BM groups supported by PPE. BM port (0-7) is for EDMA port 0,
+ * BM port (8-13) is for PPE physical port 1-6 and BM port 14 is for
+ * EIP port.
+ */
+static struct ppe_bm_port_config ipq9574_ppe_bm_port_config[] = {
+ {
+ /* Buffer configuration for the BM port ID 0 of EDMA. */
+ .port_id_start = 0,
+ .port_id_end = 0,
+ .pre_alloc = 0,
+ .in_fly_buf = 100,
+ .ceil = 1146,
+ .weight = 7,
+ .resume_offset = 8,
+ .resume_ceil = 0,
+ .dynamic = true,
+ },
+ {
+ /* Buffer configuration for the BM port ID 1-7 of EDMA. */
+ .port_id_start = 1,
+ .port_id_end = 7,
+ .pre_alloc = 0,
+ .in_fly_buf = 100,
+ .ceil = 250,
+ .weight = 4,
+ .resume_offset = 36,
+ .resume_ceil = 0,
+ .dynamic = true,
+ },
+ {
+ /* Buffer configuration for the BM port ID 8-13 of PPE ports. */
+ .port_id_start = 8,
+ .port_id_end = 13,
+ .pre_alloc = 0,
+ .in_fly_buf = 128,
+ .ceil = 250,
+ .weight = 4,
+ .resume_offset = 36,
+ .resume_ceil = 0,
+ .dynamic = true,
+ },
+ {
+ /* Buffer configuration for the BM port ID 14 of EIP. */
+ .port_id_start = 14,
+ .port_id_end = 14,
+ .pre_alloc = 0,
+ .in_fly_buf = 40,
+ .ceil = 250,
+ .weight = 4,
+ .resume_offset = 36,
+ .resume_ceil = 0,
+ .dynamic = true,
+ },
+};
+
+static int ppe_config_bm_threshold(struct ppe_device *ppe_dev, int bm_port_id,
+ struct ppe_bm_port_config port_cfg)
+{
+ u32 reg, val, bm_fc_val[2];
+ int ret;
+
+ /* Configure BM flow control related threshold. */
+ PPE_BM_PORT_FC_SET_WEIGHT(bm_fc_val, port_cfg.weight);
Hi Luo Jie,
When compiling with W=1 for x86_32 and ARM (32bit)
(but, curiously not x86_64 or arm64), gcc-14 complains that
bm_fc_val is uninitialised, I believe due to the line above and
similar lines below.
In file included from drivers/net/ethernet/qualcomm/ppe/ppe_config.c:10:
In function 'u32p_replace_bits',
inlined from 'ppe_config_bm_threshold' at drivers/net/ethernet/qualcomm/ppe/ppe_config.c:112:2:
./include/linux/bitfield.h:189:15: warning: 'bm_fc_val' is used uninitialized [-Wuninitialized]
189 | *p = (*p & ~to(field)) | type##_encode_bits(val, field); \
| ^~
./include/linux/bitfield.h:198:9: note: in expansion of macro '____MAKE_OP'
198 | ____MAKE_OP(u##size,u##size,,)
| ^~~~~~~~~~~
./include/linux/bitfield.h:201:1: note: in expansion of macro '__MAKE_OP'
201 | __MAKE_OP(32)
| ^~~~~~~~~
drivers/net/ethernet/qualcomm/ppe/ppe_config.c: In function 'ppe_config_bm_threshold':
drivers/net/ethernet/qualcomm/ppe/ppe_config.c:108:23: note: 'bm_fc_val' declared here
108 | u32 reg, val, bm_fc_val[2];
| ^~~~~~~~~
+ PPE_BM_PORT_FC_SET_RESUME_OFFSET(bm_fc_val, port_cfg.resume_offset);
+ PPE_BM_PORT_FC_SET_RESUME_THRESHOLD(bm_fc_val, port_cfg.resume_ceil);
+ PPE_BM_PORT_FC_SET_DYNAMIC(bm_fc_val, port_cfg.dynamic);
+ PPE_BM_PORT_FC_SET_REACT_LIMIT(bm_fc_val, port_cfg.in_fly_buf);
+ PPE_BM_PORT_FC_SET_PRE_ALLOC(bm_fc_val, port_cfg.pre_alloc);
+
+ /* Configure low/high bits of the ceiling for the BM port. */
+ val = FIELD_PREP(GENMASK(2, 0), port_cfg.ceil);
The value of port_cfg.ceil is 250 or 1146, as set in
ipq9574_ppe_bm_port_config. clang-19 W=1 builds complain that this
value is too large for the field (3 bits).
drivers/net/ethernet/qualcomm/ppe/ppe_config.c:120:8: error: call to '__compiletime_assert_925' declared with 'error' attribute: FIELD_PREP: value too large for the field
120 | val = FIELD_PREP(GENMASK(2, 0), port_cfg.ceil);
| ^
./include/linux/bitfield.h:115:3: note: expanded from macro 'FIELD_PREP'
115 | __BF_FIELD_CHECK(_mask, 0ULL, _val, "FIELD_PREP: "); \
| ^
./include/linux/bitfield.h:68:3: note: expanded from macro '__BF_FIELD_CHECK'
68 | BUILD_BUG_ON_MSG(__builtin_constant_p(_val) ? \
| ^
./include/linux/build_bug.h:39:37: note: expanded from macro 'BUILD_BUG_ON_MSG'
39 | #define BUILD_BUG_ON_MSG(cond, msg) compiletime_assert(!(cond), msg)
| ^
note: (skipping 1 expansions in backtrace; use -fmacro-backtrace-limit=0 to see all)
././include/linux/compiler_types.h:530:2: note: expanded from macro '_compiletime_assert'
530 | __compiletime_assert(condition, msg, prefix, suffix)
| ^
././include/linux/compiler_types.h:523:4: note: expanded from macro '__compiletime_assert'
523 | prefix ## suffix(); \
| ^
<scratch space>:95:1: note: expanded from here
95 | __compiletime_assert_925
| ^
1 error generated
+ PPE_BM_PORT_FC_SET_CEILING_LOW(bm_fc_val, val);
+ val = FIELD_PREP(GENMASK(10, 3), port_cfg.ceil);
