[PATCH v5 net-next 06/10] net: dsa: lantiq_gswip: serialize access to the PCE registers
From: Vladimir Oltean <vladimir.oltean@nxp.com>
Date: 2021-10-24 17:18:51
Subsystem:
networking drivers, networking [dsa], the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Andrew Lunn, Vladimir Oltean, Linus Torvalds
The GSWIP switch accesses various bridging layer tables (VLANs, FDBs, forwarding rules) indirectly through PCE registers. These hardware accesses are non-atomic, being comprised of several register reads and writes. These accesses are currently serialized by the rtnl_lock, but DSA is changing its driver API and that lock will no longer be held when calling ->port_fdb_add() and ->port_fdb_del(). So this driver needs to serialize the access to the PCE registers using its own locking scheme. This patch adds that. Note that the driver also uses the gswip_pce_load_microcode() function to load a static configuration for the packet classification engine into a table using the same registers. It is currently not protected, but since that configuration is only done from the dsa_switch_ops :: setup method, there is no risk of it being concurrent with other operations. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Acked-by: Hauke Mehrtens <hauke@hauke-m.de> --- v3->v4: call mutex_init v4->v5: slightly reword the commit message according to Hauke's indications drivers/net/dsa/lantiq_gswip.c | 28 +++++++++++++++++++++++----- 1 file changed, 23 insertions(+), 5 deletions(-)
diff --git a/drivers/net/dsa/lantiq_gswip.c b/drivers/net/dsa/lantiq_gswip.c
index dbd4486a173f..1a96df70d1e8 100644
--- a/drivers/net/dsa/lantiq_gswip.c
+++ b/drivers/net/dsa/lantiq_gswip.c@@ -276,6 +276,7 @@ struct gswip_priv { int num_gphy_fw; struct gswip_gphy_fw *gphy_fw; u32 port_vlan_filter; + struct mutex pce_table_lock; }; struct gswip_pce_table_entry {
@@ -523,10 +524,14 @@ static int gswip_pce_table_entry_read(struct gswip_priv *priv, u16 addr_mode = tbl->key_mode ? GSWIP_PCE_TBL_CTRL_OPMOD_KSRD : GSWIP_PCE_TBL_CTRL_OPMOD_ADRD; + mutex_lock(&priv->pce_table_lock); + err = gswip_switch_r_timeout(priv, GSWIP_PCE_TBL_CTRL, GSWIP_PCE_TBL_CTRL_BAS); - if (err) + if (err) { + mutex_unlock(&priv->pce_table_lock); return err; + } gswip_switch_w(priv, tbl->index, GSWIP_PCE_TBL_ADDR); gswip_switch_mask(priv, GSWIP_PCE_TBL_CTRL_ADDR_MASK |
@@ -536,8 +541,10 @@ static int gswip_pce_table_entry_read(struct gswip_priv *priv, err = gswip_switch_r_timeout(priv, GSWIP_PCE_TBL_CTRL, GSWIP_PCE_TBL_CTRL_BAS); - if (err) + if (err) { + mutex_unlock(&priv->pce_table_lock); return err; + } for (i = 0; i < ARRAY_SIZE(tbl->key); i++) tbl->key[i] = gswip_switch_r(priv, GSWIP_PCE_TBL_KEY(i));
@@ -553,6 +560,8 @@ static int gswip_pce_table_entry_read(struct gswip_priv *priv, tbl->valid = !!(crtl & GSWIP_PCE_TBL_CTRL_VLD); tbl->gmap = (crtl & GSWIP_PCE_TBL_CTRL_GMAP_MASK) >> 7; + mutex_unlock(&priv->pce_table_lock); + return 0; }
@@ -565,10 +574,14 @@ static int gswip_pce_table_entry_write(struct gswip_priv *priv, u16 addr_mode = tbl->key_mode ? GSWIP_PCE_TBL_CTRL_OPMOD_KSWR : GSWIP_PCE_TBL_CTRL_OPMOD_ADWR; + mutex_lock(&priv->pce_table_lock); + err = gswip_switch_r_timeout(priv, GSWIP_PCE_TBL_CTRL, GSWIP_PCE_TBL_CTRL_BAS); - if (err) + if (err) { + mutex_unlock(&priv->pce_table_lock); return err; + } gswip_switch_w(priv, tbl->index, GSWIP_PCE_TBL_ADDR); gswip_switch_mask(priv, GSWIP_PCE_TBL_CTRL_ADDR_MASK |
@@ -600,8 +613,12 @@ static int gswip_pce_table_entry_write(struct gswip_priv *priv, crtl |= GSWIP_PCE_TBL_CTRL_BAS; gswip_switch_w(priv, crtl, GSWIP_PCE_TBL_CTRL); - return gswip_switch_r_timeout(priv, GSWIP_PCE_TBL_CTRL, - GSWIP_PCE_TBL_CTRL_BAS); + err = gswip_switch_r_timeout(priv, GSWIP_PCE_TBL_CTRL, + GSWIP_PCE_TBL_CTRL_BAS); + + mutex_unlock(&priv->pce_table_lock); + + return err; } /* Add the LAN port into a bridge with the CPU port by
@@ -2106,6 +2123,7 @@ static int gswip_probe(struct platform_device *pdev) priv->ds->priv = priv; priv->ds->ops = priv->hw_info->ops; priv->dev = dev; + mutex_init(&priv->pce_table_lock); version = gswip_switch_r(priv, GSWIP_VERSION); np = dev->of_node;
--
2.25.1