[PATCH] arch/ppc/8xx_io/enet.c, version 2
Stephan Linke
Stephan.Linke at epygi.de
Tue Oct 29 02:17:07 EST 2002
Hi Jocke,
I just had a look at the code. So far it is running fine. on my board. :)
Following question:
In scc-enet_rx you use invalidate_dcache_range() for the skb data area.
Why don't you do the same in scc_enet_init() for the first set of skb's?
Isn't it required too at this place.
Thanks, Stephan
> -----Original Message-----
> From: owner-linuxppc-embedded at lists.linuxppc.org
> [mailto:owner-linuxppc-embedded at lists.linuxppc.org]On Behalf Of Joakim
> Tjernlund
> Sent: Donnerstag, 24. Oktober 2002 16:24
> To: linuxppc-embedded at lists.linuxppc.org
> Cc: scop at digitel.com.br; thomas at corelatus.com
> Subject: [PATCH] arch/ppc/8xx_io/enet.c, version 2
>
>
>
> Hi
>
> This is the second version of my patch that removes the expensive
> memcpy of
> received
> ethernet frames in interrupt context.
>
> I have 1 report(from Ricardo Scop) of 20% increase in
> packets/second, packet
> size 1500 when
> applied to 8260 FEC(needs to be applied manually). But min packet size
> decreased with 10 %.
> This version should fix the 10% decrease case.
>
> This patch could be adapted 8xx_io/fec.c and 8260_io/enet.c and
> 8260/fcc_enet.c with little effort.
>
> Better fix a bug in set_multicast_list(), move the dmi list forward when
> walking it(dmi = dmi->next;)
>
> New stuff:
> - Configrable: copy small packets or pass them directly, see
> COPY_SMALL_FRAMES in code.
> - Collision reporting fix form Thomas Lange.
> - Don't pass receive frames which has error upwards.
> - Report RX_OV errors as fifo errors, not crc errors.
>
> Please test and report any problems and performace improvements.
>
> Jocke
>
> --- arch/ppc/8xx_io/enet.c.org Mon Oct 21 14:35:59 2002
> +++ arch/ppc/8xx_io/enet.c Thu Oct 24 15:48:25 2002
> @@ -34,7 +34,6 @@
> #include <linux/ioport.h>
> #include <linux/slab.h>
> #include <linux/interrupt.h>
> -#include <linux/pci.h>
> #include <linux/init.h>
> #include <linux/delay.h>
> #include <linux/netdevice.h>
> @@ -86,6 +85,14 @@
> * All functions are directly controlled using I/O pins. See
> <asm/commproc.h>.
> */
>
> +/* Define COPY_SMALL_FRAMES if you want to save buffer memory for small
> packets
> + * at a small performance hit. Note performance testing needed */
> +#define COPY_SMALL_FRAMES 1
> +
> +#ifdef COPY_SMALL_FRAMES
> + #define RX_COPYBREAK (256-16) /* dev_alloc_skb() adds 16 bytes for
> internal use */
> +#endif
> +
> /* The transmitter timeout
> */
> #define TX_TIMEOUT (2*HZ)
> @@ -97,19 +104,17 @@
> * the skbuffer directly.
> */
> #ifdef CONFIG_ENET_BIG_BUFFERS
> -#define CPM_ENET_RX_PAGES 32
> -#define CPM_ENET_RX_FRSIZE 2048
> -#define CPM_ENET_RX_FRPPG (PAGE_SIZE / CPM_ENET_RX_FRSIZE)
> -#define RX_RING_SIZE (CPM_ENET_RX_FRPPG * CPM_ENET_RX_PAGES)
> -#define TX_RING_SIZE 64 /* Must be power of two */
> -#define TX_RING_MOD_MASK 63 /* for this to work */
> + #define RX_RING_SIZE 64
> + #define TX_RING_SIZE 64 /* Must be power of
> two for this to work */
> #else
> -#define CPM_ENET_RX_PAGES 4
> -#define CPM_ENET_RX_FRSIZE 2048
> -#define CPM_ENET_RX_FRPPG (PAGE_SIZE / CPM_ENET_RX_FRSIZE)
> -#define RX_RING_SIZE (CPM_ENET_RX_FRPPG * CPM_ENET_RX_PAGES)
> -#define TX_RING_SIZE 8 /* Must be power of two */
> -#define TX_RING_MOD_MASK 7 /* for this to work */
> + #define RX_RING_SIZE 8
> + #define TX_RING_SIZE 8 /* Must be power of
> two for this to work */
> +#endif
> +#define TX_RING_MOD_MASK (TX_RING_SIZE-1)
> +
> +#define CPM_ENET_RX_FRSIZE 1600 /* must be a multiple of cache line */
> +#if CPM_ENET_RX_FRSIZE % L1_CACHE_LINE_SIZE != 0
> + #error CPM_ENET_RX_FRSIZE must be a multiple of L1 cache size
> #endif
>
> /* The CPM stores dest/src/type, data, and checksum for receive packets.
> @@ -143,7 +148,7 @@
> /* Virtual addresses for the receive buffers because we can't
> * do a __va() on them anymore.
> */
> - unsigned char *rx_vaddr[RX_RING_SIZE];
> + void *rx_vaddr[RX_RING_SIZE];
> struct net_device_stats stats;
> uint tx_full;
> spinlock_t lock;
> @@ -370,11 +375,11 @@
>
> cep->stats.tx_packets++;
>
> - /* Deferred means some collisions occurred during transmit,
> - * but we eventually sent the packet OK.
> - */
> - if (bdp->cbd_sc & BD_ENET_TX_DEF)
> - cep->stats.collisions++;
> + /* Check retry counter, i.e. collision counter */
> + if (bdp->cbd_sc & BD_ENET_TX_RCMASK){
> + /* Note that counter cannot go higher than 15 */
> + cep->stats.collisions+=(bdp->cbd_sc &
> BD_ENET_TX_RCMASK)>>2;
> + }
>
> /* Free the sk buffer associated with this last transmit.
> */
> @@ -449,6 +454,7 @@
> struct scc_enet_private *cep;
> volatile cbd_t *bdp;
> struct sk_buff *skb;
> + struct sk_buff *skb_tmp;
> ushort pkt_len;
>
> cep = (struct scc_enet_private *)dev->priv;
> @@ -461,7 +467,8 @@
> for (;;) {
> if (bdp->cbd_sc & BD_ENET_RX_EMPTY)
> break;
> -
> +
> +#define RX_BD_ERRORS (BD_ENET_RX_LG | BD_ENET_RX_SH | BD_ENET_RX_NO |
> BD_ENET_RX_CR | BD_ENET_RX_OV | BD_ENET_RX_CL)
> #ifndef final_version
> /* Since we have allocated space to hold a complete frame, both
> * the first and last indicators should be set.
> @@ -470,51 +477,62 @@
> (BD_ENET_RX_FIRST | BD_ENET_RX_LAST))
> printk("CPM ENET: rcv is not first+last\n");
> #endif
> -
> - /* Frame too long or too short.
> - */
> - if (bdp->cbd_sc & (BD_ENET_RX_LG | BD_ENET_RX_SH))
> - cep->stats.rx_length_errors++;
> - if (bdp->cbd_sc & BD_ENET_RX_NO) /* Frame alignment */
> - cep->stats.rx_frame_errors++;
> - if (bdp->cbd_sc & BD_ENET_RX_CR) /* CRC Error */
> - cep->stats.rx_crc_errors++;
> - if (bdp->cbd_sc & BD_ENET_RX_OV) /* FIFO overrun */
> - cep->stats.rx_crc_errors++;
> -
> - /* Report late collisions as a frame error.
> - * On this error, the BD is closed, but we don't know what we
> - * have in the buffer. So, just drop this frame on the floor.
> - */
> - if (bdp->cbd_sc & BD_ENET_RX_CL) {
> - cep->stats.rx_frame_errors++;
> - }
> - else {
> -
> + if(bdp->cbd_sc & RX_BD_ERRORS){ /* Receive errors ? */
> + cep->stats.rx_errors++;
> + if (bdp->cbd_sc & (BD_ENET_RX_LG | BD_ENET_RX_SH))
> /* Frame too long or
> too short. */
> + cep->stats.rx_length_errors++;
> + if (bdp->cbd_sc & BD_ENET_RX_NO) /* Frame
> alignment */
> + cep->stats.rx_frame_errors++;
> + if (bdp->cbd_sc & BD_ENET_RX_CR) /* CRC Error */
> + cep->stats.rx_crc_errors++;
> + if (bdp->cbd_sc & BD_ENET_RX_OV) /* FIFO overrun */
> + cep->stats.rx_fifo_errors++;
> + if (bdp->cbd_sc & BD_ENET_RX_CL) /* Late collision */
> + cep->stats.collisions++;
> + } else {
> /* Process the incoming frame.
> */
> cep->stats.rx_packets++;
> pkt_len = bdp->cbd_datlen;
> cep->stats.rx_bytes += pkt_len;
> -
> - /* This does 16 byte alignment, much more than we need.
> - * The packet length includes FCS, but we don't want to
> - * include that when passing upstream as it messes up
> - * bridging applications.
> - */
> - skb = dev_alloc_skb(pkt_len-4);
> -
> - if (skb == NULL) {
> + pkt_len -= 4; /* The packet length includes FCS,
> but we don't want to
> + * include that when passing upstream
> as it messes up
> + * bridging applications. Is this
> still true ???? */
> +#ifdef COPY_SMALL_FRAMES
> + /* Allocate the next buffer now so we are sure to
> have one when needed
> + * This does 16 byte alignment, exactly what we
> need(L1_CACHE aligned). */
> + if(pkt_len < RX_COPYBREAK)
> + skb_tmp = __dev_alloc_skb(pkt_len,
> GFP_ATOMIC|GFP_DMA);
> + else
> +#endif
> + skb_tmp =
> __dev_alloc_skb(CPM_ENET_RX_FRSIZE, GFP_ATOMIC|GFP_DMA);
> +
> + if (skb_tmp == NULL) {
> printk("%s: Memory squeeze, dropping
> packet.\n", dev->name);
> cep->stats.rx_dropped++;
> - }
> - else {
> +
> + } else {
> + skb = cep->rx_vaddr[bdp - cep->rx_bd_base];
> + invalidate_dcache_range((unsigned long) skb->data,
> + (unsigned long)
> skb->data + pkt_len);
> +
> +#ifdef COPY_SMALL_FRAMES
> + if(pkt_len < RX_COPYBREAK) {
> + typeof(skb) skb_swap = skb;
> + memcpy(skb_put(skb_tmp, pkt_len),
> skb->data, pkt_len);
> + /* swap the skb and skb_tmp */
> + skb = skb_tmp;
> + skb_tmp = skb_swap;
> + }
> + else
> +#endif
> + {
> + skb_put(skb, pkt_len); /* Make room */
> + bdp->cbd_bufaddr = __pa(skb_tmp->data);
> + cep->rx_vaddr[bdp -
> cep->rx_bd_base] = skb_tmp;
> + }
> skb->dev = dev;
> - skb_put(skb,pkt_len-4); /* Make room */
> - eth_copy_and_sum(skb,
> - cep->rx_vaddr[bdp - cep->rx_bd_base],
> - pkt_len-4, 0);
> - skb->protocol=eth_type_trans(skb,dev);
> + skb->protocol=eth_type_trans(skb, dev);
> netif_rx(skb);
> }
> }
> @@ -608,7 +626,7 @@
>
> dmi = dev->mc_list;
>
> - for (i=0; i<dev->mc_count; i++) {
> + for (i=0; i<dev->mc_count; i++, dmi = dmi->next) {
>
> /* Only support group multicast for now.
> */
> @@ -647,8 +665,7 @@
> struct net_device *dev;
> struct scc_enet_private *cep;
> int i, j, k;
> - unsigned char *eap, *ba;
> - dma_addr_t mem_addr;
> + unsigned char *eap;
> bd_t *bd;
> volatile cbd_t *bdp;
> volatile cpm8xx_t *cp;
> @@ -839,22 +856,13 @@
>
> bdp = cep->rx_bd_base;
> k = 0;
> - for (i=0; i<CPM_ENET_RX_PAGES; i++) {
> -
> - /* Allocate a page.
> - */
> - ba = (unsigned char *)consistent_alloc(GFP_KERNEL,
> PAGE_SIZE, &mem_addr);
> -
> - /* Initialize the BD for every fragment in the page.
> - */
> - for (j=0; j<CPM_ENET_RX_FRPPG; j++) {
> - bdp->cbd_sc = BD_ENET_RX_EMPTY | BD_ENET_RX_INTR;
> - bdp->cbd_bufaddr = mem_addr;
> - cep->rx_vaddr[k++] = ba;
> - mem_addr += CPM_ENET_RX_FRSIZE;
> - ba += CPM_ENET_RX_FRSIZE;
> - bdp++;
> - }
> + /* Initialize the BDs. */
> + for (j=0; j < RX_RING_SIZE; j++) {
> + struct sk_buff * skb = __dev_alloc_skb(CPM_ENET_RX_FRSIZE,
> GFP_ATOMIC|GFP_DMA);
> + bdp->cbd_sc = BD_ENET_RX_EMPTY | BD_ENET_RX_INTR;
> + bdp->cbd_bufaddr = __pa(skb->data);
> + cep->rx_vaddr[k++] = skb;
> + bdp++;
> }
>
> /* Set the last buffer to wrap.
>
>
>
>
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