Re: [PATCH 1/4] net: macb: Add support for PTP timestamps in DMA descriptors

From: Richard Cochran
Date: Fri Apr 14 2017 - 03:43:38 EST


On Thu, Apr 13, 2017 at 02:33:59PM +0100, Rafal Ozieblo wrote:
> @@ -1921,9 +1972,13 @@ static void macb_configure_dma(struct macb *bp)
> dmacfg &= ~GEM_BIT(TXCOEN);
>
> #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> - if (bp->hw_dma_cap == HW_DMA_CAP_64B)
> + if (bp->hw_dma_cap & HW_DMA_CAP_64B)
> dmacfg |= GEM_BIT(ADDR64);
> #endif
> +#ifdef CONFIG_MACB_USE_HWSTAMP
> + if (bp->hw_dma_cap & HW_DMA_CAP_PTP)
> + dmacfg |= GEM_BIT(RXEXT) | GEM_BIT(TXEXT);
> +#endif
> netdev_dbg(bp->dev, "Cadence configure DMA with 0x%08x\n",
> dmacfg);
> gem_writel(bp, DMACFG, dmacfg);
> @@ -1971,14 +2026,15 @@ static void macb_init_hw(struct macb *bp)
> /* Initialize TX and RX buffers */
> macb_writel(bp, RBQP, lower_32_bits(bp->rx_ring_dma));
> #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> - if (bp->hw_dma_cap == HW_DMA_CAP_64B)
> + if (bp->hw_dma_cap & HW_DMA_CAP_64B)
> macb_writel(bp, RBQPH, upper_32_bits(bp->rx_ring_dma));
> #endif
> for (q = 0, queue = bp->queues; q < bp->num_queues; ++q, ++queue) {
> queue_writel(queue, TBQP, lower_32_bits(queue->tx_ring_dma));
> #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> - if (bp->hw_dma_cap == HW_DMA_CAP_64B)
> - queue_writel(queue, TBQPH, upper_32_bits(queue->tx_ring_dma));
> + if (bp->hw_dma_cap & HW_DMA_CAP_64B)
> + queue_writel(queue, TBQPH,
> + upper_32_bits(queue->tx_ring_dma));

Align arg3 with arg1 please.

> #endif
>
> /* Enable interrupts */
> @@ -2579,6 +2635,18 @@ static void macb_configure_caps(struct macb *bp,
> dcfg = gem_readl(bp, DCFG2);
> if ((dcfg & (GEM_BIT(RX_PKT_BUFF) | GEM_BIT(TX_PKT_BUFF))) == 0)
> bp->caps |= MACB_CAPS_FIFO_MODE;
> + /* if HWSTAMP is configure and gem has the capability */

This comment is redundant. We can see that clearly in the code already.

> +#ifdef CONFIG_MACB_USE_HWSTAMP
> + bp->ptp_hw_support = false;

No need to clear this again. (The struct was cleared after
allocation, right?)

> + if (gem_has_ptp(bp)) {

Why not drop the #idef:

if (IS_ENABLED(CONFIG_MACB_USE_HWSTAMP) && gem_has_ptp(bp)) ...

> + if (!GEM_BFEXT(TSU, gem_readl(bp, DCFG5)))
> + pr_err("GEM doesn't support hardware ptp.\n");
> + else {
> + pr_emerg("rozieblo: ptp_hw_support = true");

pr_emerg?

> + bp->ptp_hw_support = true;
> + }

Proper if/else CodingStyle please.

> + }
> +#endif
> }
>
> dev_dbg(&bp->pdev->dev, "Cadence caps 0x%08x\n", bp->caps);

> @@ -2716,7 +2784,7 @@ static int macb_init(struct platform_device *pdev)
> queue->IMR = GEM_IMR(hw_q - 1);
> queue->TBQP = GEM_TBQP(hw_q - 1);
> #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> - if (bp->hw_dma_cap == HW_DMA_CAP_64B)
> + if (bp->hw_dma_cap & HW_DMA_CAP_64B)
> queue->TBQPH = GEM_TBQPH(hw_q - 1);
> #endif
> } else {
> @@ -2727,7 +2795,7 @@ static int macb_init(struct platform_device *pdev)
> queue->IMR = MACB_IMR;
> queue->TBQP = MACB_TBQP;
> #ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> - if (bp->hw_dma_cap == HW_DMA_CAP_64B)
> + if (bp->hw_dma_cap & HW_DMA_CAP_64B)
> queue->TBQPH = MACB_TBQPH;
> #endif
> }

> @@ -3307,19 +3375,24 @@ static int macb_probe(struct platform_device *pdev)
> bp->wol |= MACB_WOL_HAS_MAGIC_PACKET;
> device_init_wakeup(&pdev->dev, bp->wol & MACB_WOL_HAS_MAGIC_PACKET);
>
> -#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> - if (GEM_BFEXT(DAW64, gem_readl(bp, DCFG6))) {
> - dma_set_mask(&pdev->dev, DMA_BIT_MASK(44));
> - bp->hw_dma_cap = HW_DMA_CAP_64B;
> - } else
> - bp->hw_dma_cap = HW_DMA_CAP_32B;
> -#endif
> -
> spin_lock_init(&bp->lock);
>
> /* setup capabilities */
> macb_configure_caps(bp, macb_config);
>
> +#ifdef MACB_EXT_DESC
> + bp->hw_dma_cap = HW_DMA_CAP_32B;
> +#endif
> +#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> + if (GEM_BFEXT(DAW64, gem_readl(bp, DCFG6))) {
> + dma_set_mask(&pdev->dev, DMA_BIT_MASK(44));
> + bp->hw_dma_cap |= HW_DMA_CAP_64B;
> + }
> +#endif
> +#ifdef CONFIG_MACB_USE_HWSTAMP
> + if (bp->ptp_hw_support)
> + bp->hw_dma_cap |= HW_DMA_CAP_PTP;

So bp->ptp_hw_support is a waste of storage. You can test for
(!GEM_BFEXT(TSU, gem_readl(bp, DCFG5))) directly here, or return a
flag from macb_configure_caps(), or set the hw_dma_cap flag in that
function, ...

> +#endif
> platform_set_drvdata(pdev, dev);
>
> dev->irq = platform_get_irq(pdev, 0);

> @@ -954,8 +972,12 @@ struct macb {
> u32 wol;
>
> struct macb_ptp_info *ptp_info; /* macb-ptp interface */
> -#ifdef CONFIG_ARCH_DMA_ADDR_T_64BIT
> - enum macb_hw_dma_cap hw_dma_cap;
> +#ifdef MACB_EXT_DESC
> + uint8_t hw_dma_cap;
> +#endif
> +
> +#ifdef CONFIG_MACB_USE_HWSTAMP
> + bool ptp_hw_support;

Remove this, please.

Thanks,
Richard

> #endif
> };
>
> --
> 2.4.5
>