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From: Radhey Shyam Pandey <radheys@xilinx.com>
To: Andre Przywara <andre.przywara@arm.com>,
	"David S . Miller" <davem@davemloft.net>
Cc: Michal Simek <michals@xilinx.com>,
	Robert Hancock <hancock@sedsystems.ca>,
	"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH 05/14] net: axienet: Factor out TX descriptor chain cleanup
Date: Fri, 10 Jan 2020 18:04:57 +0000
Message-ID: <CH2PR02MB70003A0D500B9A78697FC311C7380@CH2PR02MB7000.namprd02.prod.outlook.com> (raw)
In-Reply-To: <20200110115415.75683-6-andre.przywara@arm.com>

> -----Original Message-----
> From: Andre Przywara <andre.przywara@arm.com>
> Sent: Friday, January 10, 2020 5:24 PM
> To: David S . Miller <davem@davemloft.net>; Radhey Shyam Pandey
> <radheys@xilinx.com>
> Cc: Michal Simek <michals@xilinx.com>; Robert Hancock
> <hancock@sedsystems.ca>; netdev@vger.kernel.org; linux-arm-
> kernel@lists.infradead.org; linux-kernel@vger.kernel.org
> Subject: [PATCH 05/14] net: axienet: Factor out TX descriptor chain cleanup
> 
> Factor out the code that cleans up a number of connected TX descriptors,
> as we will need it to properly roll back a failed _xmit() call.
> There are subtle differences between cleaning up a successfully sent
> chain (unknown number of involved descriptors, total data size needed)
> and a chain that was about to set up (number of descriptors known), so
> cater for those variations with some extra parameters.
> 
> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
> ---
>  .../net/ethernet/xilinx/xilinx_axienet_main.c | 75 ++++++++++++-------
>  1 file changed, 50 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> index ec5d01adc1d5..82abe2b0f16a 100644
> --- a/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> +++ b/drivers/net/ethernet/xilinx/xilinx_axienet_main.c
> @@ -543,33 +543,37 @@ static int axienet_device_reset(struct net_device
> *ndev)
>  	return 0;
>  }
> 
> -/**
> - * axienet_start_xmit_done - Invoked once a transmit is completed by the
> - * Axi DMA Tx channel.
> - * @ndev:	Pointer to the net_device structure
> - *
> - * This function is invoked from the Axi DMA Tx isr to notify the completion
> - * of transmit operation. It clears fields in the corresponding Tx BDs and
> - * unmaps the corresponding buffer so that CPU can regain ownership of
> the
> - * buffer. It finally invokes "netif_wake_queue" to restart transmission if
> - * required.
> +/* Clean up a series of linked TX descriptors. Would either be called
> + * after a successful transmit operation, or after there was an error
> + * when setting up the chain.
> + * Returns the number of descriptors handled.
>   */
> -static void axienet_start_xmit_done(struct net_device *ndev)

To be consistent we can add the doxygen function description.
The rest looks good. Feel free to add:
Reviewed-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>

> +static int axienet_free_tx_chain(struct net_device *ndev, u32 first_bd,
> +				 int nr_bds, u32 *sizep)
>  {
> -	u32 size = 0;
> -	u32 packets = 0;
>  	struct axienet_local *lp = netdev_priv(ndev);
> +	int max_bds = (nr_bds != -1) ? nr_bds : lp->tx_bd_num;
>  	struct axidma_bd *cur_p;
> -	unsigned int status = 0;
> +	unsigned int status;
> +	int i;
> +
> +	for (i = 0; i < max_bds; i++) {
> +		cur_p = &lp->tx_bd_v[(first_bd + i) % lp->tx_bd_num];
> +		status = cur_p->status;
> +
> +		/* If no number is given, clean up *all* descriptors that have
> +		 * been completed by the MAC.
> +		 */
> +		if (nr_bds == -1 && !(status &
> XAXIDMA_BD_STS_COMPLETE_MASK))
> +			break;
> 
> -	cur_p = &lp->tx_bd_v[lp->tx_bd_ci];
> -	status = cur_p->status;
> -	while (status & XAXIDMA_BD_STS_COMPLETE_MASK) {
>  		dma_unmap_single(ndev->dev.parent, cur_p->phys,
>  				(cur_p->cntrl &
> XAXIDMA_BD_CTRL_LENGTH_MASK),
>  				DMA_TO_DEVICE);
> -		if (cur_p->skb)
> +
> +		if (cur_p->skb && (status &
> XAXIDMA_BD_STS_COMPLETE_MASK))
>  			dev_consume_skb_irq(cur_p->skb);
> +
>  		cur_p->cntrl = 0;
>  		cur_p->app0 = 0;
>  		cur_p->app1 = 0;
> @@ -578,15 +582,36 @@ static void axienet_start_xmit_done(struct
> net_device *ndev)
>  		cur_p->status = 0;
>  		cur_p->skb = NULL;
> 
> -		size += status & XAXIDMA_BD_STS_ACTUAL_LEN_MASK;
> -		packets++;
> -
> -		if (++lp->tx_bd_ci >= lp->tx_bd_num)
> -			lp->tx_bd_ci = 0;
> -		cur_p = &lp->tx_bd_v[lp->tx_bd_ci];
> -		status = cur_p->status;
> +		if (sizep)
> +			*sizep += status &
> XAXIDMA_BD_STS_ACTUAL_LEN_MASK;
>  	}
> 
> +	return i;
> +}
> +
> +/**
> + * axienet_start_xmit_done - Invoked once a transmit is completed by the
> + * Axi DMA Tx channel.
> + * @ndev:	Pointer to the net_device structure
> + *
> + * This function is invoked from the Axi DMA Tx isr to notify the completion
> + * of transmit operation. It clears fields in the corresponding Tx BDs and
> + * unmaps the corresponding buffer so that CPU can regain ownership of
> the
> + * buffer. It finally invokes "netif_wake_queue" to restart transmission if
> + * required.
> + */
> +static void axienet_start_xmit_done(struct net_device *ndev)
> +{
> +	u32 size = 0;
> +	u32 packets = 0;
> +	struct axienet_local *lp = netdev_priv(ndev);
> +
> +	packets = axienet_free_tx_chain(ndev, lp->tx_bd_ci, -1, &size);
> +
> +	lp->tx_bd_ci += packets;
> +	if (lp->tx_bd_ci >= lp->tx_bd_num)
> +		lp->tx_bd_ci -= lp->tx_bd_num;
> +
>  	ndev->stats.tx_packets += packets;
>  	ndev->stats.tx_bytes += size;
> 
> --
> 2.17.1


  reply index

Thread overview: 57+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-10 11:54 [PATCH 00/14] net: axienet: Error handling, SGMII and 64-bit DMA fixes Andre Przywara
2020-01-10 11:54 ` [PATCH 01/14] net: xilinx: temac: Relax Kconfig dependencies Andre Przywara
2020-01-10 14:19   ` Radhey Shyam Pandey
2020-01-10 11:54 ` [PATCH 02/14] net: axienet: Propagate failure of DMA descriptor setup Andre Przywara
2020-01-10 14:54   ` Radhey Shyam Pandey
2020-01-10 17:53     ` Radhey Shyam Pandey
2020-01-10 11:54 ` [PATCH 03/14] net: axienet: Fix DMA descriptor cleanup path Andre Przywara
2020-01-10 15:14   ` Radhey Shyam Pandey
2020-01-10 15:43     ` Andre Przywara
2020-01-10 17:05       ` Radhey Shyam Pandey
2020-01-16 18:03         ` Andre Przywara
2020-01-20 18:32           ` Radhey Shyam Pandey
2020-01-10 11:54 ` [PATCH 04/14] net: axienet: Improve DMA error handling Andre Przywara
2020-01-10 15:26   ` Radhey Shyam Pandey
2020-01-10 11:54 ` [PATCH 05/14] net: axienet: Factor out TX descriptor chain cleanup Andre Przywara
2020-01-10 18:04   ` Radhey Shyam Pandey [this message]
2020-01-10 11:54 ` [PATCH 06/14] net: axienet: Check for DMA mapping errors Andre Przywara
2020-01-13  5:54   ` Radhey Shyam Pandey
2020-01-10 11:54 ` [PATCH 07/14] net: axienet: Fix SGMII support Andre Przywara
2020-01-10 14:04   ` Andrew Lunn
2020-01-10 14:20     ` Andre Przywara
2020-01-10 14:26       ` Andrew Lunn
2020-01-10 15:04       ` Russell King - ARM Linux admin
2020-01-10 15:22         ` Russell King - ARM Linux admin
2020-01-10 17:04           ` Russell King - ARM Linux admin
2020-01-18 11:22             ` Russell King - ARM Linux admin
2020-01-20 14:50               ` Andre Przywara
2020-01-20 15:45                 ` Russell King - ARM Linux admin
2020-01-27 17:04                   ` Andre Przywara
2020-01-27 17:20                     ` Radhey Shyam Pandey
2020-01-27 18:53                     ` Russell King - ARM Linux admin
2020-01-10 14:58   ` Russell King - ARM Linux admin
2020-01-10 17:32     ` Andre Przywara
2020-01-10 18:05       ` Russell King - ARM Linux admin
2020-01-10 19:33         ` Andrew Lunn
2020-01-10 11:54 ` [PATCH 08/14] net: axienet: Drop MDIO interrupt registers from ethtools dump Andre Przywara
2020-01-13  6:02   ` Radhey Shyam Pandey
2020-01-10 11:54 ` [PATCH 09/14] net: axienet: Add mii-tool support Andre Przywara
2020-01-13  6:12   ` Radhey Shyam Pandey
2020-01-10 11:54 ` [PATCH 10/14] net: axienet: Wrap DMA pointer writes to prepare for 64 bit Andre Przywara
2020-01-10 11:54 ` [PATCH 11/14] net: axienet: Upgrade descriptors to hold 64-bit addresses Andre Przywara
2020-01-14 16:35   ` Radhey Shyam Pandey
2020-01-14 17:29     ` Andre Przywara
2020-01-10 11:54 ` [PATCH 12/14] net: axienet: Autodetect 64-bit DMA capability Andre Przywara
2020-01-10 14:08   ` Andrew Lunn
2020-01-10 14:13     ` Andre Przywara
2020-01-10 14:22       ` Andrew Lunn
2020-01-10 15:08         ` Andre Przywara
2020-01-10 15:22           ` Andrew Lunn
2020-01-14 17:03   ` Radhey Shyam Pandey
2020-01-14 17:41     ` Andre Przywara
2020-01-15  6:02       ` Radhey Shyam Pandey
2020-01-10 11:54 ` [PATCH 13/14] net: axienet: Allow DMA to beyond 4GB Andre Przywara
2020-01-10 11:54 ` [PATCH 14/14] net: axienet: Update devicetree binding documentation Andre Przywara
2020-01-21 21:51   ` Rob Herring
2020-01-24 16:29     ` Andre Przywara
2020-01-27  9:28       ` Radhey Shyam Pandey

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