From mboxrd@z Thu Jan 1 00:00:00 1970 From: Max Uvarov Subject: [PATCHv3 1/2] drivers: net: davinci_mdio: remove busy loop on wait user access Date: Fri, 11 Aug 2017 13:57:40 +0300 Message-ID: <1502449061-30373-2-git-send-email-muvarov@gmail.com> References: <1502449061-30373-1-git-send-email-muvarov@gmail.com> Return-path: In-Reply-To: <1502449061-30373-1-git-send-email-muvarov@gmail.com> Sender: netdev-owner@vger.kernel.org To: netdev@vger.kernel.org Cc: linux-omap@vger.kernel.org, grygorii.strashko@ti.com, Max Uvarov List-Id: linux-omap@vger.kernel.org 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 Reviewed-by: Andrew Lunn Reviewed-by: Grygorii Strashko --- 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