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Subject[PATCH] nfp: convert nfp_eth_set_bit_config() into a macro
Date
nfp_eth_set_bit_config() is marked as __always_inline to allow gcc to
identify the 'mask' parameter as known to be constant at compile time,
which is required to use the FIELD_GET() macro.

The forced inlining does the trick for gcc, but for kernel builds with
clang it results in undefined symbols:

drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.o: In function
`__nfp_eth_set_aneg':
drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c:(.text+0x787):
undefined reference to `__compiletime_assert_492'
drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c:(.text+0x7b1):
undefined reference to `__compiletime_assert_496'

These __compiletime_assert_xyx() calls would have been optimized away if
the compiler had seen 'mask' as a constant.

Convert nfp_eth_set_bit_config() into a macro, which allows both gcc and
clang to identify 'mask' as a compile time constant.

Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
---
I am aware that a lengthy macro is not a pretty solution, I'm open for
better suggestions.

Note: The patch has been build-tested only since I don't have any NFP
hardware.

.../ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c | 67 +++++++++++-----------
1 file changed, 34 insertions(+), 33 deletions(-)

diff --git a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c
index f6f7c085f8e0..e9c635867918 100644
--- a/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c
+++ b/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_nsp_eth.c
@@ -469,39 +469,40 @@ int nfp_eth_set_configured(struct nfp_cpp *cpp, unsigned int idx, bool configed)
return nfp_eth_config_commit_end(nsp);
}

-/* Force inline, FIELD_* macroes require masks to be compilation-time known */
-static __always_inline int
-nfp_eth_set_bit_config(struct nfp_nsp *nsp, unsigned int raw_idx,
- const u64 mask, unsigned int val, const u64 ctrl_bit)
-{
- union eth_table_entry *entries = nfp_nsp_config_entries(nsp);
- unsigned int idx = nfp_nsp_config_idx(nsp);
- u64 reg;
-
- /* Note: set features were added in ABI 0.14 but the error
- * codes were initially not populated correctly.
- */
- if (nfp_nsp_get_abi_ver_minor(nsp) < 17) {
- nfp_err(nfp_nsp_cpp(nsp),
- "set operations not supported, please update flash\n");
- return -EOPNOTSUPP;
- }
-
- /* Check if we are already in requested state */
- reg = le64_to_cpu(entries[idx].raw[raw_idx]);
- if (val == FIELD_GET(mask, reg))
- return 0;
-
- reg &= ~mask;
- reg |= FIELD_PREP(mask, val);
- entries[idx].raw[raw_idx] = cpu_to_le64(reg);
-
- entries[idx].control |= cpu_to_le64(ctrl_bit);
-
- nfp_nsp_config_set_modified(nsp, true);
-
- return 0;
-}
+#define nfp_eth_set_bit_config(nsp, raw_idx, mask, val, ctrl_bit) \
+({ \
+ union eth_table_entry *entries = nfp_nsp_config_entries(nsp); \
+ unsigned int idx = nfp_nsp_config_idx(nsp); \
+ u64 reg; \
+ int rc; \
+ \
+ /* Note: set features were added in ABI 0.14 but the error */ \
+ /* codes were initially not populated correctly. */ \
+ if (nfp_nsp_get_abi_ver_minor(nsp) < 17) { \
+ nfp_err(nfp_nsp_cpp(nsp), \
+ "set operations not supported, please update flash\n"); \
+ rc = -EOPNOTSUPP; \
+ goto out; \
+ } \
+ \
+ rc = 0; \
+ \
+ /* Check if we are already in requested state */ \
+ reg = le64_to_cpu(entries[idx].raw[raw_idx]); \
+ if (val == FIELD_GET(mask, reg)) \
+ goto out; \
+ \
+ reg &= ~mask; \
+ reg |= FIELD_PREP(mask, val); \
+ entries[idx].raw[raw_idx] = cpu_to_le64(reg); \
+ \
+ entries[idx].control |= cpu_to_le64(ctrl_bit); \
+ \
+ nfp_nsp_config_set_modified(nsp, true); \
+ \
+out: \
+ rc; \
+})

/**
* __nfp_eth_set_aneg() - set PHY autonegotiation control bit
--
2.14.2.920.gcf0c67979c-goog
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