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Date: Fri, 11 Aug 2017 13:57:40 +0300 From: Max Uvarov <muvarov@...il.com> To: netdev@...r.kernel.org Cc: linux-omap@...r.kernel.org, grygorii.strashko@...com, Max Uvarov <muvarov@...il.com> Subject: [PATCHv3 1/2] drivers: net: davinci_mdio: remove busy loop on wait user access Polling 14 mdio devices on single mdio bus eats 30% of 1Ghz cpu time due to busy loop in wait(). Add small delay to relax cpu. Signed-off-by: Max Uvarov <muvarov@...il.com> Reviewed-by: Andrew Lunn <andrew@...n.ch> Reviewed-by: Grygorii Strashko <grygorii.strashko@...com> --- drivers/net/ethernet/ti/davinci_mdio.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/drivers/net/ethernet/ti/davinci_mdio.c b/drivers/net/ethernet/ti/davinci_mdio.c index 33df340..611e7cc 100644 --- a/drivers/net/ethernet/ti/davinci_mdio.c +++ b/drivers/net/ethernet/ti/davinci_mdio.c @@ -198,8 +198,10 @@ static inline int wait_for_user_access(struct davinci_mdio_data *data) return 0; reg = __raw_readl(®s->control); - if ((reg & CONTROL_IDLE) == 0) + if ((reg & CONTROL_IDLE) == 0) { + usleep_range(100, 200); continue; + } /* * An emac soft_reset may have clobbered the mdio controller's -- 2.5.0
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