The ICSSG driver does the initial FDB configuration which
includes setting the control registers. Other run time
management like learning is managed by the PRU's. The default
FDB hash size used by the firmware is 512 slots, which is
currently missing in the current driver. Update the driver
FDB config to include FDB hash size as well.

Please refer trm [1] 6.4.14.12.17 section on how the FDB config
register gets configured. From the table 6-1404, there is a reset
field for FDB_HAS_SIZE which is 4, meaning 1024 slots. Currently
the driver is not updating this reset value from 4(1024 slots) to
3(512 slots). This patch fixes this by updating the reset value
to 512 slots.

[1]: https://www.ti.com/lit/pdf/spruim2
Fixes: abd5576b9c57f ("net: ti: icssg-prueth: Add support for ICSSG switch firmware")
Signed-off-by: Meghana Malladi <m-malladi@ti.com>
---

v2-v1:
- Update the commit message and give more context w.r.t hardware
  for the fix as suggested by Simon Horman <horms@kernel.org>

v1: https://lore.kernel.org/all/20251013085925.1391999-1-m-malladi@ti.com/

 drivers/net/ethernet/ti/icssg/icssg_config.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/ethernet/ti/icssg/icssg_config.c b/drivers/net/ethernet/ti/icssg/icssg_config.c
index da53eb04b0a4..3f8237c17d09 100644
--- a/drivers/net/ethernet/ti/icssg/icssg_config.c
+++ b/drivers/net/ethernet/ti/icssg/icssg_config.c
@@ -66,6 +66,9 @@
 #define FDB_GEN_CFG1		0x60
 #define SMEM_VLAN_OFFSET	8
 #define SMEM_VLAN_OFFSET_MASK	GENMASK(25, 8)
+#define FDB_HASH_SIZE_MASK	GENMASK(6, 3)
+#define FDB_HASH_SIZE_SHIFT	3
+#define FDB_HASH_SIZE		3
 
 #define FDB_GEN_CFG2		0x64
 #define FDB_VLAN_EN		BIT(6)
@@ -463,6 +466,8 @@ void icssg_init_emac_mode(struct prueth *prueth)
 	/* Set VLAN TABLE address base */
 	regmap_update_bits(prueth->miig_rt, FDB_GEN_CFG1, SMEM_VLAN_OFFSET_MASK,
 			   addr <<  SMEM_VLAN_OFFSET);
+	regmap_update_bits(prueth->miig_rt, FDB_GEN_CFG1, FDB_HASH_SIZE_MASK,
+			   FDB_HASH_SIZE << FDB_HASH_SIZE_SHIFT);
 	/* Set enable VLAN aware mode, and FDBs for all PRUs */
 	regmap_write(prueth->miig_rt, FDB_GEN_CFG2, (FDB_PRU0_EN | FDB_PRU1_EN | FDB_HOST_EN));
 	prueth->vlan_tbl = (struct prueth_vlan_tbl __force *)(prueth->shram.va +
@@ -484,6 +489,8 @@ void icssg_init_fw_offload_mode(struct prueth *prueth)
 	/* Set VLAN TABLE address base */
 	regmap_update_bits(prueth->miig_rt, FDB_GEN_CFG1, SMEM_VLAN_OFFSET_MASK,
 			   addr <<  SMEM_VLAN_OFFSET);
+	regmap_update_bits(prueth->miig_rt, FDB_GEN_CFG1, FDB_HASH_SIZE_MASK,
+			   FDB_HASH_SIZE << FDB_HASH_SIZE_SHIFT);
 	/* Set enable VLAN aware mode, and FDBs for all PRUs */
 	regmap_write(prueth->miig_rt, FDB_GEN_CFG2, FDB_EN_ALL);
 	prueth->vlan_tbl = (struct prueth_vlan_tbl __force *)(prueth->shram.va +

base-commit: e120f46768d98151ece8756ebd688b0e43dc8b29
-- 
2.43.0

On Tue, Nov 04, 2025 at 04:14:15PM +0530, Meghana Malladi wrote:
> The ICSSG driver does the initial FDB configuration which
> includes setting the control registers. Other run time
> management like learning is managed by the PRU's. The default
> FDB hash size used by the firmware is 512 slots, which is
> currently missing in the current driver. Update the driver
> FDB config to include FDB hash size as well.
> 
> Please refer trm [1] 6.4.14.12.17 section on how the FDB config
> register gets configured. From the table 6-1404, there is a reset
> field for FDB_HAS_SIZE which is 4, meaning 1024 slots. Currently
> the driver is not updating this reset value from 4(1024 slots) to
> 3(512 slots). This patch fixes this by updating the reset value
> to 512 slots.
> 
> [1]: https://www.ti.com/lit/pdf/spruim2
> Fixes: abd5576b9c57f ("net: ti: icssg-prueth: Add support for ICSSG switch firmware")
> Signed-off-by: Meghana Malladi <m-malladi@ti.com>
> ---
> 
> v2-v1:
> - Update the commit message and give more context w.r.t hardware
>   for the fix as suggested by Simon Horman <horms@kernel.org>
> 
> v1: https://lore.kernel.org/all/20251013085925.1391999-1-m-malladi@ti.com/

Thanks for the updated commit message, this seems much clearer to me.

Sorry for not responding to your reply to my review of v1. For some
reason I missed it until I checked the link above a few moments ago.

Reviewed-by: Simon Horman <horms@kernel.org>