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net: dsa: bcm_sf2: fix crossbar port bitwidth logic

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The SF2 crossbar register is a packed bitfield, giving the index of the
external port selected for each of the internal ports. On BCM4908 (the
only currently-supported switch family with a crossbar), there are 2
internal ports and 3 external ports, so there are 2 bits per internal
port.

The driver currently conflates the "bits per port" and "number of ports"
concepts, lumping both into the `num_crossbar_int_ports` field. Since it
is currently only possible for either of these counts to have a value of
2, there is no behavioral error resulting from this situation for now.

Make the code more readable (and support the future possibility of
larger crossbars) by adding a `num_crossbar_ext_bits` field to represent
the "bits per port" count and relying on this where appropriate instead.

Signed-off-by: Sam Edwards <CFSworks@gmail.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Link: https://patch.msgid.link/20241003212301.1339647-1-CFSworks@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Sam Edwards 2024-10-03 14:23:01 -07:00 committed by Jakub Kicinski
parent 0da7fb3bca
commit 41378cfdc4
2 changed files with 7 additions and 3 deletions
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9
drivers/net/dsa/bcm_sf2.c
View File

@ -513,12 +513,12 @@ static void bcm_sf2_crossbar_setup(struct bcm_sf2_priv *priv)
u32 reg;
int i;
mask = BIT(priv->num_crossbar_int_ports) - 1;
mask = BIT(priv->num_crossbar_ext_bits) - 1;
reg = reg_readl(priv, REG_CROSSBAR);
switch (priv->type) {
case BCM4908_DEVICE_ID:
shift = CROSSBAR_BCM4908_INT_P7 * priv->num_crossbar_int_ports;
shift = CROSSBAR_BCM4908_INT_P7 * priv->num_crossbar_ext_bits;
reg &= ~(mask << shift);
if (0) /* FIXME */
reg |= CROSSBAR_BCM4908_EXT_SERDES << shift;
@ -536,7 +536,7 @@ static void bcm_sf2_crossbar_setup(struct bcm_sf2_priv *priv)
reg = reg_readl(priv, REG_CROSSBAR);
for (i = 0; i < priv->num_crossbar_int_ports; i++) {
shift = i * priv->num_crossbar_int_ports;
shift = i * priv->num_crossbar_ext_bits;
dev_dbg(dev, "crossbar int port #%d - ext port #%d\n", i,
(reg >> shift) & mask);
@ -1260,6 +1260,7 @@ struct bcm_sf2_of_data {
unsigned int core_reg_align;
unsigned int num_cfp_rules;
unsigned int num_crossbar_int_ports;
unsigned int num_crossbar_ext_bits;
};
static const u16 bcm_sf2_4908_reg_offsets[] = {
@ -1288,6 +1289,7 @@ static const struct bcm_sf2_of_data bcm_sf2_4908_data = {
.reg_offsets = bcm_sf2_4908_reg_offsets,
.num_cfp_rules = 256,
.num_crossbar_int_ports = 2,
.num_crossbar_ext_bits = 2,
};
/* Register offsets for the SWITCH_REG_* block */
@ -1399,6 +1401,7 @@ static int bcm_sf2_sw_probe(struct platform_device *pdev)
priv->core_reg_align = data->core_reg_align;
priv->num_cfp_rules = data->num_cfp_rules;
priv->num_crossbar_int_ports = data->num_crossbar_int_ports;
priv->num_crossbar_ext_bits = data->num_crossbar_ext_bits;
priv->rcdev = devm_reset_control_get_optional_exclusive(&pdev->dev,
"switch");

1
drivers/net/dsa/bcm_sf2.h
View File

@ -75,6 +75,7 @@ struct bcm_sf2_priv {
unsigned int core_reg_align;
unsigned int num_cfp_rules;
unsigned int num_crossbar_int_ports;
unsigned int num_crossbar_ext_bits;
/* spinlock protecting access to the indirect registers */
spinlock_t indir_lock;