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thunderbolt: Increase sideband access polling delay
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The USB4 sideband access is slow compared to the high-speed link and the
access timing parameters are tens of milliseconds according the spec. To
avoid too much unnecessary polling for the sideband pass the wait delay
to usb4_port_wait_for_bit() and use larger (5ms) value compared to the
high-speed access.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
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Mika Westerberg committed Apr 23, 2024
1 parent c936e28 commit c6ca1ac
Showing 1 changed file with 15 additions and 7 deletions.
22 changes: 15 additions & 7 deletions drivers/thunderbolt/usb4.c
Original file line number Diff line number Diff line change
Expand Up @@ -52,6 +52,10 @@ enum usb4_ba_index {
#define USB4_BA_VALUE_MASK GENMASK(31, 16)
#define USB4_BA_VALUE_SHIFT 16

/* Delays in us used with usb4_port_wait_for_bit() */
#define USB4_PORT_DELAY 50
#define USB4_PORT_SB_DELAY 5000

static int usb4_native_switch_op(struct tb_switch *sw, u16 opcode,
u32 *metadata, u8 *status,
const void *tx_data, size_t tx_dwords,
Expand Down Expand Up @@ -1244,7 +1248,7 @@ void usb4_port_unconfigure_xdomain(struct tb_port *port)
}

static int usb4_port_wait_for_bit(struct tb_port *port, u32 offset, u32 bit,
u32 value, int timeout_msec)
u32 value, int timeout_msec, unsigned long delay_usec)
{
ktime_t timeout = ktime_add_ms(ktime_get(), timeout_msec);

Expand All @@ -1259,7 +1263,7 @@ static int usb4_port_wait_for_bit(struct tb_port *port, u32 offset, u32 bit,
if ((val & bit) == value)
return 0;

usleep_range(50, 100);
fsleep(delay_usec);
} while (ktime_before(ktime_get(), timeout));

return -ETIMEDOUT;
Expand Down Expand Up @@ -1307,7 +1311,7 @@ static int usb4_port_sb_read(struct tb_port *port, enum usb4_sb_target target,
return ret;

ret = usb4_port_wait_for_bit(port, port->cap_usb4 + PORT_CS_1,
PORT_CS_1_PND, 0, 500);
PORT_CS_1_PND, 0, 500, USB4_PORT_SB_DELAY);
if (ret)
return ret;

Expand Down Expand Up @@ -1354,7 +1358,7 @@ static int usb4_port_sb_write(struct tb_port *port, enum usb4_sb_target target,
return ret;

ret = usb4_port_wait_for_bit(port, port->cap_usb4 + PORT_CS_1,
PORT_CS_1_PND, 0, 500);
PORT_CS_1_PND, 0, 500, USB4_PORT_SB_DELAY);
if (ret)
return ret;

Expand Down Expand Up @@ -1409,6 +1413,8 @@ static int usb4_port_sb_op(struct tb_port *port, enum usb4_sb_target target,

if (val != opcode)
return usb4_port_sb_opcode_err_to_errno(val);

fsleep(USB4_PORT_SB_DELAY);
} while (ktime_before(ktime_get(), timeout));

return -ETIMEDOUT;
Expand Down Expand Up @@ -1590,13 +1596,14 @@ int usb4_port_asym_start(struct tb_port *port)
* port started the symmetry transition.
*/
ret = usb4_port_wait_for_bit(port, port->cap_usb4 + PORT_CS_19,
PORT_CS_19_START_ASYM, 0, 1000);
PORT_CS_19_START_ASYM, 0, 1000,
USB4_PORT_DELAY);
if (ret)
return ret;

/* Then wait for the transtion to be completed */
return usb4_port_wait_for_bit(port, port->cap_usb4 + PORT_CS_18,
PORT_CS_18_TIP, 0, 5000);
PORT_CS_18_TIP, 0, 5000, USB4_PORT_DELAY);
}

/**
Expand Down Expand Up @@ -2122,7 +2129,8 @@ static int usb4_usb3_port_cm_request(struct tb_port *port, bool request)
*/
val &= ADP_USB3_CS_2_CMR;
return usb4_port_wait_for_bit(port, port->cap_adap + ADP_USB3_CS_1,
ADP_USB3_CS_1_HCA, val, 1500);
ADP_USB3_CS_1_HCA, val, 1500,
USB4_PORT_DELAY);
}

static inline int usb4_usb3_port_set_cm_request(struct tb_port *port)
Expand Down

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