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Date: Mon, 26 Oct 2009 16:49:06 +0000
From: Ben Hutchings <bhutchings@...arflare.com>
To: "Figo.zhang" <figo1802@...il.com>
Cc: Daniel Silverstone <dsilvers@...tec.co.uk>,
"David S. Miller" <davem@...emloft.net>, netdev@...r.kernel.org,
Vincent Sanders <vince@...tec.co.uk>,
Ben Dooks <ben@...tec.co.uk>
Subject: Re: [PATCH]NET/KS8695: add support NAPI for Rx
On Tue, 2009-10-27 at 00:00 +0800, Figo.zhang wrote:
> Add support NAPI Rx API for KS8695NET driver.
>
> Signed-off-by: Figo.zhang <figo1802@...il.com>
> ---
> drivers/net/arm/ks8695net.c | 165 +++++++++++++++++++++++++++++++++++++++++++
> 1 files changed, 165 insertions(+), 0 deletions(-)
>
> diff --git a/drivers/net/arm/ks8695net.c b/drivers/net/arm/ks8695net.c
> index 2a7b774..7f9d4bd 100644
> --- a/drivers/net/arm/ks8695net.c
> +++ b/drivers/net/arm/ks8695net.c
> @@ -35,12 +35,16 @@
>
> #include <mach/regs-switch.h>
> #include <mach/regs-misc.h>
> +#include <asm/mach/irq.h>
> +#include <mach/regs-irq.h>
>
> #include "ks8695net.h"
>
> #define MODULENAME "ks8695_ether"
> #define MODULEVERSION "1.01"
I think this merits a version bump.
> +#define KS8695NET_NAPI 1
> +
> /*
> * Transmit and device reset timeout, default 5 seconds.
> */
> @@ -152,6 +156,10 @@ struct ks8695_priv {
> enum ks8695_dtype dtype;
> void __iomem *io_regs;
>
> + #ifdef KS8695NET_NAPI
> + struct napi_struct napi;
> + #endif
> +
NAPI is well-established and there should be no need to make it
optional. So far as I'm aware, all other drivers that had it as an
option now use it unconditionally.
> const char *rx_irq_name, *tx_irq_name, *link_irq_name;
> int rx_irq, tx_irq, link_irq;
>
> @@ -172,6 +180,7 @@ struct ks8695_priv {
> dma_addr_t rx_ring_dma;
> struct ks8695_skbuff rx_buffers[MAX_RX_DESC];
> int next_rx_desc_read;
> + spinlock_t rx_lock;
>
> int msg_enable;
> };
> @@ -391,6 +400,155 @@ ks8695_tx_irq(int irq, void *dev_id)
> return IRQ_HANDLED;
> }
>
> +#ifdef KS8695NET_NAPI
> +static irqreturn_t
> +ks8695_rx_irq(int irq, void *dev_id)
> +{
> + struct net_device *ndev = (struct net_device *)dev_id;
> + struct ks8695_priv *ksp = netdev_priv(ndev);
> + unsigned long status;
> +
> + unsigned long mask_bit = 1 << ksp->rx_irq;
> +
> + spin_lock(&ksp->rx_lock);
> +
> + status = __raw_readl(KS8695_IRQ_VA + KS8695_INTST);
> +
> + /*clean rx status bit*/
> + __raw_writel(status | mask_bit , KS8695_IRQ_VA + KS8695_INTST);
> +
> + if (status & mask_bit) {
> + if (napi_schedule_prep(&ksp->napi)) {
> + /*disable rx interrupt*/
> + status &= ~mask_bit;
> + __raw_writel(status , KS8695_IRQ_VA + KS8695_INTEN);
> + __napi_schedule(&ksp->napi);
> + }
> + }
> +
> + spin_unlock(&ksp->rx_lock);
> + return IRQ_HANDLED;
> +}
The interrupt register manipulation here looks wrong, but I don't have
specific knowledge of this platform.
Since the interrupt control registers appear to be shared with other
devices, this needs to be serialised with manipulation by other drivers.
> +static int ks8695_rx(struct net_device *ndev, int budget)
> +{
> + struct ks8695_priv *ksp = netdev_priv(ndev);
> + struct sk_buff *skb;
> + int buff_n;
> + u32 flags;
> + int pktlen;
> + int last_rx_processed = -1;
> + int received = 0;
> +
> + buff_n = ksp->next_rx_desc_read;
> + while (netif_running(ndev) && received < budget
netif_running() is quite redundant here.
> + && ksp->rx_buffers[buff_n].skb
> + && (!(ksp->rx_ring[buff_n].status &
> + cpu_to_le32(RDES_OWN)))) {
> + rmb();
> + flags = le32_to_cpu(ksp->rx_ring[buff_n].status);
> + /* Found an SKB which we own, this means we
> + * received a packet
> + */
> + if ((flags & (RDES_FS | RDES_LS)) !=
> + (RDES_FS | RDES_LS)) {
> + /* This packet is not the first and
> + * the last segment. Therefore it is
> + * a "spanning" packet and we can't
> + * handle it
> + */
> + goto rx_failure;
> + }
> +
> + if (flags & (RDES_ES | RDES_RE)) {
> + /* It's an error packet */
> + ndev->stats.rx_errors++;
> + if (flags & RDES_TL)
> + ndev->stats.rx_length_errors++;
> + if (flags & RDES_RF)
> + ndev->stats.rx_length_errors++;
> + if (flags & RDES_CE)
> + ndev->stats.rx_crc_errors++;
> + if (flags & RDES_RE)
> + ndev->stats.rx_missed_errors++;
> +
> + goto rx_failure;
> + }
> +
> + pktlen = flags & RDES_FLEN;
> + pktlen -= 4; /* Drop the CRC */
> +
> + /* Retrieve the sk_buff */
> + skb = ksp->rx_buffers[buff_n].skb;
> +
> + /* Clear it from the ring */
> + ksp->rx_buffers[buff_n].skb = NULL;
> + ksp->rx_ring[buff_n].data_ptr = 0;
> +
> + /* Unmap the SKB */
> + dma_unmap_single(ksp->dev,
> + ksp->rx_buffers[buff_n].dma_ptr,
> + ksp->rx_buffers[buff_n].length,
> + DMA_FROM_DEVICE);
> +
> + /* Relinquish the SKB to the network layer */
> + skb_put(skb, pktlen);
> + skb->protocol = eth_type_trans(skb, ndev);
> + netif_receive_skb(skb);
> +
> + /* Record stats */
> + ndev->stats.rx_packets++;
> + ndev->stats.rx_bytes += pktlen;
> + goto rx_finished;
> +
> +rx_failure:
> + /* This ring entry is an error, but we can
> + * re-use the skb
> + */
> + /* Give the ring entry back to the hardware */
> + ksp->rx_ring[buff_n].status = cpu_to_le32(RDES_OWN);
> +rx_finished:
> + received++;
> + /* And note this as processed so we can start
> + * from here next time
> + */
> + last_rx_processed = buff_n;
> + buff_n = (buff_n + 1) & MAX_RX_DESC_MASK;
> + /*And note which RX descriptor we last did */
> + if (likely(last_rx_processed != -1))
> + ksp->next_rx_desc_read =
> + (last_rx_processed + 1) &
> + MAX_RX_DESC_MASK;
> +
> + /* And refill the buffers */
> + ks8695_refill_rxbuffers(ksp);
> + }
> + return received;
> +}
> +
> +static int ks8695_poll(struct napi_struct *napi, int budget)
> +{
> + struct ks8695_priv *ksp = container_of(napi, struct ks8695_priv, napi);
> + struct net_device *dev = ksp->ndev;
> + unsigned long mask_bit = 1 << ksp->rx_irq;
> + unsigned long isr = __raw_readl(KS8695_IRQ_VA + KS8695_INTEN);
This is surely the wrong place to be reading this register.
> + unsigned long work_done = 0;
Pointless initialisation.
> +
> + work_done = ks8695_rx(dev, budget);
> +
> + if (work_done < budget) {
> + unsigned long flags;
> + spin_lock_irqsave(&ksp->rx_lock, flags);
> + /*enable rx interrupt*/
> + __raw_writel(isr | mask_bit, KS8695_IRQ_VA + KS8695_INTEN);
> + __napi_complete(napi);
> + spin_unlock_irqrestore(&ksp->rx_lock, flags);
> + }
> + return work_done;
> +}
> +
> +#else
> /**
> * ks8695_rx_irq - Receive IRQ handler
> * @irq: The IRQ which went off (ignored)
> @@ -503,6 +661,8 @@ rx_finished:
> return IRQ_HANDLED;
> }
>
> +#endif
> +
> /**
> * ks8695_link_irq - Link change IRQ handler
> * @irq: The IRQ which went off (ignored)
> @@ -1472,6 +1632,10 @@ ks8695_probe(struct platform_device *pdev)
> SET_ETHTOOL_OPS(ndev, &ks8695_ethtool_ops);
> ndev->watchdog_timeo = msecs_to_jiffies(watchdog);
>
> +#ifdef KS8695NET_NAPI
> + netif_napi_add(ndev, &ksp->napi, ks8695_poll, 64);
> +#endif
> +
> /* Retrieve the default MAC addr from the chip. */
> /* The bootloader should have left it in there for us. */
>
> @@ -1505,6 +1669,7 @@ ks8695_probe(struct platform_device *pdev)
>
> /* And initialise the queue's lock */
> spin_lock_init(&ksp->txq_lock);
> + spin_lock_init(&ksp->rx_lock);
>
> /* Specify the RX DMA ring buffer */
> ksp->rx_ring = ksp->ring_base + TX_RING_DMA_SIZE;
You're missing a netif_napi_del() on removal.
Ben.
--
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
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