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net: phy: mscc-miim: read poll when high resolution timers are disabled 

The driver uses a read polling mechanism to check the status of the MDIO
bus, to know if it is ready to accept next commands. This polling
mechanism uses usleep_delay() under the hood between reads which is fine
as long as high resolution timers are enabled. Otherwise the delays will
end up to be much longer than expected.

This patch fixes this by using udelay() under the hood when
CONFIG_HIGH_RES_TIMERS isn't enabled. This increases CPU usage.

Signed-off-by: Antoine Tenart <antoine.tenart@bootlin.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Antoine Tenart 2020-05-26 18:22:56 +02:00 committed by David S. Miller
parent d9c6de35e0
commit a021ada2b7
2 changed files with 19 additions and 6 deletions
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3
drivers/net/phy/Kconfig
View File

@ -184,7 +184,8 @@ config MDIO_MSCC_MIIM
depends on HAS_IOMEM
help
This driver supports the MIIM (MDIO) interface found in the network
switches of the Microsemi SoCs
switches of the Microsemi SoCs; it is recommended to switch on
CONFIG_HIGH_RES_TIMERS
config MDIO_MVUSB
tristate "Marvell USB to MDIO Adapter"

22
drivers/net/phy/mdio-mscc-miim.c
View File

@ -39,13 +39,25 @@ struct mscc_miim_dev {
void __iomem *phy_regs;
};
/* When high resolution timers aren't built-in: we can't use usleep_range() as
* we would sleep way too long. Use udelay() instead.
*/
#define mscc_readl_poll_timeout(addr, val, cond, delay_us, timeout_us) \
({ \
if (!IS_ENABLED(CONFIG_HIGH_RES_TIMERS)) \
readl_poll_timeout_atomic(addr, val, cond, delay_us, \
timeout_us); \
readl_poll_timeout(addr, val, cond, delay_us, timeout_us); \
})
static int mscc_miim_wait_ready(struct mii_bus *bus)
{
struct mscc_miim_dev *miim = bus->priv;
u32 val;
return readl_poll_timeout(miim->regs + MSCC_MIIM_REG_STATUS, val,
!(val & MSCC_MIIM_STATUS_STAT_BUSY), 50, 10000);
return mscc_readl_poll_timeout(miim->regs + MSCC_MIIM_REG_STATUS, val,
!(val & MSCC_MIIM_STATUS_STAT_BUSY), 50,
10000);
}
static int mscc_miim_wait_pending(struct mii_bus *bus)
@ -53,9 +65,9 @@ static int mscc_miim_wait_pending(struct mii_bus *bus)
struct mscc_miim_dev *miim = bus->priv;
u32 val;
return readl_poll_timeout(miim->regs + MSCC_MIIM_REG_STATUS, val,
!(val & MSCC_MIIM_STATUS_STAT_PENDING),
50, 10000);
return mscc_readl_poll_timeout(miim->regs + MSCC_MIIM_REG_STATUS, val,
!(val & MSCC_MIIM_STATUS_STAT_PENDING),
50, 10000);
}
static int mscc_miim_read(struct mii_bus *bus, int mii_id, int regnum)