From: Tobias Waldekranz tobias@waldekranz.com
[ Upstream commit 7dd12fe34686d89c332b1a05104d18d728591f0a ]
Before this change, when operating in polled mode, i.e. no IRQ is available, every individual C45 access would be hit with a 150us sleep after the bus access.
For example, on a board with a CN9130 SoC connected to an MV88X3310 PHY, a single C45 read would take around 165us:
root@infix:~$ mdio f212a600.mdio-mii mmd 4:1 bench 0xc003 Performed 1000 reads in 165ms
By replacing the long sleep with a tighter poll loop, we observe a 10x increase in bus throughput:
root@infix:~$ mdio f212a600.mdio-mii mmd 4:1 bench 0xc003 Performed 1000 reads in 15ms
Signed-off-by: Tobias Waldekranz tobias@waldekranz.com Reviewed-by: Andrew Lunn andrew@lunn.ch Tested-by: Andrew Lunn andrew@lunn.ch Link: https://lore.kernel.org/r/20231204100811.2708884-3-tobias@waldekranz.com Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/marvell/mvmdio.c | 53 ++++++++------------------- 1 file changed, 16 insertions(+), 37 deletions(-)
diff --git a/drivers/net/ethernet/marvell/mvmdio.c b/drivers/net/ethernet/marvell/mvmdio.c index ef878973b859..b4c576e79a95 100644 --- a/drivers/net/ethernet/marvell/mvmdio.c +++ b/drivers/net/ethernet/marvell/mvmdio.c @@ -23,6 +23,7 @@ #include <linux/delay.h> #include <linux/interrupt.h> #include <linux/io.h> +#include <linux/iopoll.h> #include <linux/kernel.h> #include <linux/module.h> #include <linux/of_device.h> @@ -58,11 +59,6 @@ * - Armada 370 (Globalscale Mirabox): 41us to 43us (Polled) */ #define MVMDIO_SMI_TIMEOUT 1000 /* 1000us = 1ms */ -#define MVMDIO_SMI_POLL_INTERVAL_MIN 45 -#define MVMDIO_SMI_POLL_INTERVAL_MAX 55 - -#define MVMDIO_XSMI_POLL_INTERVAL_MIN 150 -#define MVMDIO_XSMI_POLL_INTERVAL_MAX 160
struct orion_mdio_dev { void __iomem *regs; @@ -84,8 +80,6 @@ enum orion_mdio_bus_type {
struct orion_mdio_ops { int (*is_done)(struct orion_mdio_dev *); - unsigned int poll_interval_min; - unsigned int poll_interval_max; };
/* Wait for the SMI unit to be ready for another operation @@ -94,34 +88,23 @@ static int orion_mdio_wait_ready(const struct orion_mdio_ops *ops, struct mii_bus *bus) { struct orion_mdio_dev *dev = bus->priv; - unsigned long timeout = usecs_to_jiffies(MVMDIO_SMI_TIMEOUT); - unsigned long end = jiffies + timeout; - int timedout = 0; + unsigned long timeout; + int done;
- while (1) { - if (ops->is_done(dev)) + if (dev->err_interrupt <= 0) { + if (!read_poll_timeout_atomic(ops->is_done, done, done, 2, + MVMDIO_SMI_TIMEOUT, false, dev)) + return 0; + } else { + /* wait_event_timeout does not guarantee a delay of at + * least one whole jiffie, so timeout must be no less + * than two. + */ + timeout = max(usecs_to_jiffies(MVMDIO_SMI_TIMEOUT), 2); + + if (wait_event_timeout(dev->smi_busy_wait, + ops->is_done(dev), timeout)) return 0; - else if (timedout) - break; - - if (dev->err_interrupt <= 0) { - usleep_range(ops->poll_interval_min, - ops->poll_interval_max); - - if (time_is_before_jiffies(end)) - ++timedout; - } else { - /* wait_event_timeout does not guarantee a delay of at - * least one whole jiffie, so timeout must be no less - * than two. - */ - if (timeout < 2) - timeout = 2; - wait_event_timeout(dev->smi_busy_wait, - ops->is_done(dev), timeout); - - ++timedout; - } }
dev_err(bus->parent, "Timeout: SMI busy for too long\n"); @@ -135,8 +118,6 @@ static int orion_mdio_smi_is_done(struct orion_mdio_dev *dev)
static const struct orion_mdio_ops orion_mdio_smi_ops = { .is_done = orion_mdio_smi_is_done, - .poll_interval_min = MVMDIO_SMI_POLL_INTERVAL_MIN, - .poll_interval_max = MVMDIO_SMI_POLL_INTERVAL_MAX, };
static int orion_mdio_smi_read(struct mii_bus *bus, int mii_id, @@ -200,8 +181,6 @@ static int orion_mdio_xsmi_is_done(struct orion_mdio_dev *dev)
static const struct orion_mdio_ops orion_mdio_xsmi_ops = { .is_done = orion_mdio_xsmi_is_done, - .poll_interval_min = MVMDIO_XSMI_POLL_INTERVAL_MIN, - .poll_interval_max = MVMDIO_XSMI_POLL_INTERVAL_MAX, };
static int orion_mdio_xsmi_read(struct mii_bus *bus, int mii_id,