Re: [PATCH] net/macb: fix ISR clear-on-write behavior only for some SoC

From: Jean-Christophe PLAGNIOL-VILLARD
Date: Mon May 13 2013 - 12:06:14 EST



On May 14, 2013, at 12:05 AM, Nicolas Ferre <nicolas.ferre@xxxxxxxxx> wrote:

> Commit 749a2b6 (net/macb: clear tx/rx completion flags in ISR)
> introduces clear-on-write on ISR register. This behavior is not always
> implemented when using Cadence MACB/GEM and is breaking other platforms.
> We are using a new Device Tree compatibility string and a capability
> property to actually activate this clear-on-write behavior on ISR.
>
> Reported-by: Hein Tibosch <hein_tibosch@xxxxxxxx>
> Signed-off-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxx>

can we detect it via the IP?
> ---
> Documentation/devicetree/bindings/net/macb.txt | 2 ++
> drivers/net/ethernet/cadence/macb.c | 15 +++++++++++++--
> drivers/net/ethernet/cadence/macb.h | 5 +++++
> 3 files changed, 20 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/net/macb.txt b/Documentation/devicetree/bindings/net/macb.txt
> index 44afa0e..13ec4f6 100644
> --- a/Documentation/devicetree/bindings/net/macb.txt
> +++ b/Documentation/devicetree/bindings/net/macb.txt
> @@ -6,6 +6,8 @@ Required properties:
> Use "cdns,at32ap7000-macb" for other 10/100 usage or use the generic form: "cdns,macb".
> Use "cnds,pc302-gem" for Picochip picoXcell pc302 and later devices based on
> the Cadence GEM, or the generic form: "cdns,gem".
> + Use "cdns,zynq-7000-gem" for devices based on Cadence GEM with alternative
> + options enabled (ISR clear on write).
> - reg: Address and length of the register set for the device
> - interrupts: Should contain macb interrupt
> - phy-mode: String, operation mode of the PHY interface.
> diff --git a/drivers/net/ethernet/cadence/macb.c b/drivers/net/ethernet/cadence/macb.c
> index 6be513d..628f2b0 100644
> --- a/drivers/net/ethernet/cadence/macb.c
> +++ b/drivers/net/ethernet/cadence/macb.c
> @@ -485,7 +485,8 @@ static void macb_tx_interrupt(struct macb *bp)
> status = macb_readl(bp, TSR);
> macb_writel(bp, TSR, status);
>
> - macb_writel(bp, ISR, MACB_BIT(TCOMP));
> + if (bp->caps & MACB_CAPS_ISR_CLEAR_ON_WRITE)
> + macb_writel(bp, ISR, MACB_BIT(TCOMP));
>
> netdev_vdbg(bp->dev, "macb_tx_interrupt status = 0x%03lx\n",
> (unsigned long)status);
> @@ -738,7 +739,8 @@ static irqreturn_t macb_interrupt(int irq, void *dev_id)
> * now.
> */
> macb_writel(bp, IDR, MACB_RX_INT_FLAGS);
> - macb_writel(bp, ISR, MACB_BIT(RCOMP));
> + if (bp->caps & MACB_CAPS_ISR_CLEAR_ON_WRITE)
> + macb_writel(bp, ISR, MACB_BIT(RCOMP));
>
> if (napi_schedule_prep(&bp->napi)) {
> netdev_vdbg(bp->dev, "scheduling RX softirq\n");
> @@ -1474,6 +1476,10 @@ static const struct of_device_id macb_dt_ids[] = {
> { .compatible = "cdns,macb" },
> { .compatible = "cdns,pc302-gem" },
> { .compatible = "cdns,gem" },
> + {
> + .compatible = "cdns,zynq-7000-gem",
> + .data = (void *)MACB_CAPS_ISR_CLEAR_ON_WRITE,
> + },
> { /* sentinel */ }
> };
> MODULE_DEVICE_TABLE(of, macb_dt_ids);
> @@ -1484,6 +1490,7 @@ static int __init macb_probe(struct platform_device *pdev)
> struct macb_platform_data *pdata;
> struct resource *regs;
> struct net_device *dev;
> + const struct of_device_id *dev_id;
> struct macb *bp;
> struct phy_device *phydev;
> u32 config;
> @@ -1558,6 +1565,10 @@ static int __init macb_probe(struct platform_device *pdev)
>
> dev->base_addr = regs->start;
>
> + dev_id = of_match_device(macb_dt_ids, &pdev->dev);
> + if (dev_id)
> + bp->caps = (u32)dev_id->data;
> +
> /* Set MII management clock divider */
> config = macb_mdc_clk_div(bp);
> config |= macb_dbw(bp);
> diff --git a/drivers/net/ethernet/cadence/macb.h b/drivers/net/ethernet/cadence/macb.h
> index 993d703..5d622fe 100644
> --- a/drivers/net/ethernet/cadence/macb.h
> +++ b/drivers/net/ethernet/cadence/macb.h
> @@ -323,6 +323,9 @@
> #define MACB_MAN_READ 2
> #define MACB_MAN_CODE 2
>
> +/* Capability mask bits */
> +#define MACB_CAPS_ISR_CLEAR_ON_WRITE 0x1
> +
> /* Bit manipulation macros */
> #define MACB_BIT(name) \
> (1 << MACB_##name##_OFFSET)
> @@ -574,6 +577,8 @@ struct macb {
> unsigned int speed;
> unsigned int duplex;
>
> + u32 caps;
> +
> phy_interface_t phy_interface;
>
> /* AT91RM9200 transmit */
> --
> 1.8.0
>

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