[V3] PCI: rcar: Poll more often in rcar_pcie_wait_for_dl()
diff mbox series

Message ID 20180522122420.24002-1-marek.vasut+renesas@gmail.com
State Accepted
Delegated to: Lorenzo Pieralisi
Headers show
Series
  • [V3] PCI: rcar: Poll more often in rcar_pcie_wait_for_dl()
Related show

Commit Message

Marek Vasut May 22, 2018, 12:24 p.m. UTC
The data link active signal usually takes ~20 uSec to be asserted,
poll the bit more often to avoid useless delays in this function.
Use udelay() instead of usleep() for such a small delay as suggested
by the timer documentation and because this will be used in atomic
context later on when the suspend/resume patches land.

Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
Cc: Geert Uytterhoeven <geert+renesas@glider.be>
Cc: Phil Edworthy <phil.edworthy@renesas.com>
Cc: Simon Horman <horms+renesas@verge.net.au>
Cc: Wolfram Sang <wsa@the-dreams.de>
Cc: linux-renesas-soc@vger.kernel.org
---
V2: s/content/context in commit message
V3: Add cpu_relax()
---
 drivers/pci/host/pcie-rcar.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

Comments

Simon Horman May 22, 2018, 1:16 p.m. UTC | #1
On Tue, May 22, 2018 at 02:24:20PM +0200, Marek Vasut wrote:
> The data link active signal usually takes ~20 uSec to be asserted,
> poll the bit more often to avoid useless delays in this function.
> Use udelay() instead of usleep() for such a small delay as suggested
> by the timer documentation and because this will be used in atomic
> context later on when the suspend/resume patches land.
> 
> Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
> Cc: Phil Edworthy <phil.edworthy@renesas.com>
> Cc: Simon Horman <horms+renesas@verge.net.au>
> Cc: Wolfram Sang <wsa@the-dreams.de>
> Cc: linux-renesas-soc@vger.kernel.org

Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Lorenzo Pieralisi May 24, 2018, 5:04 p.m. UTC | #2
On Tue, May 22, 2018 at 02:24:20PM +0200, Marek Vasut wrote:
> The data link active signal usually takes ~20 uSec to be asserted,
> poll the bit more often to avoid useless delays in this function.
> Use udelay() instead of usleep() for such a small delay as suggested
> by the timer documentation and because this will be used in atomic
> context later on when the suspend/resume patches land.
> 
> Signed-off-by: Marek Vasut <marek.vasut+renesas@gmail.com>
> Cc: Geert Uytterhoeven <geert+renesas@glider.be>
> Cc: Phil Edworthy <phil.edworthy@renesas.com>
> Cc: Simon Horman <horms+renesas@verge.net.au>
> Cc: Wolfram Sang <wsa@the-dreams.de>
> Cc: linux-renesas-soc@vger.kernel.org
> ---
> V2: s/content/context in commit message
> V3: Add cpu_relax()
> ---
>  drivers/pci/host/pcie-rcar.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)

Applied to pci/rcar for v4.18, thanks.

Lorenzo

> diff --git a/drivers/pci/host/pcie-rcar.c b/drivers/pci/host/pcie-rcar.c
> index 5c365f743df5..3aa6fe5f2d64 100644
> --- a/drivers/pci/host/pcie-rcar.c
> +++ b/drivers/pci/host/pcie-rcar.c
> @@ -529,13 +529,14 @@ static void phy_write_reg(struct rcar_pcie *pcie,
>  
>  static int rcar_pcie_wait_for_dl(struct rcar_pcie *pcie)
>  {
> -	unsigned int timeout = 10;
> +	unsigned int timeout = 10000;
>  
>  	while (timeout--) {
>  		if ((rcar_pci_read_reg(pcie, PCIETSTR) & DATA_LINK_ACTIVE))
>  			return 0;
>  
> -		msleep(5);
> +		udelay(5);
> +		cpu_relax();
>  	}
>  
>  	return -ETIMEDOUT;
> -- 
> 2.16.2
>

Patch
diff mbox series

diff --git a/drivers/pci/host/pcie-rcar.c b/drivers/pci/host/pcie-rcar.c
index 5c365f743df5..3aa6fe5f2d64 100644
--- a/drivers/pci/host/pcie-rcar.c
+++ b/drivers/pci/host/pcie-rcar.c
@@ -529,13 +529,14 @@  static void phy_write_reg(struct rcar_pcie *pcie,
 
 static int rcar_pcie_wait_for_dl(struct rcar_pcie *pcie)
 {
-	unsigned int timeout = 10;
+	unsigned int timeout = 10000;
 
 	while (timeout--) {
 		if ((rcar_pci_read_reg(pcie, PCIETSTR) & DATA_LINK_ACTIVE))
 			return 0;
 
-		msleep(5);
+		udelay(5);
+		cpu_relax();
 	}
 
 	return -ETIMEDOUT;