[PATCH 8/12] spidernet: separate hardware state from driver state.

From: Linas Vepstas
Date: Tue Feb 20 2007 - 17:40:37 EST


This patch separates the hardware descriptor state from the
driver descriptor state, per (old) suggestion from Ben Herrenschmidt.
This compiles and boots and seems to work.

Signed-off-by: Linas Vepstas <linas@xxxxxxxxxxxxxx>
Cc: Jens Osterkamp <Jens.Osterkamp@xxxxxxxxxx>
Cc: Kou Ishizaki <kou.ishizaki@xxxxxxxxxxxxx>

----
drivers/net/spider_net.c | 150 ++++++++++++++++++++++++++---------------------
drivers/net/spider_net.h | 16 +++--
2 files changed, 95 insertions(+), 71 deletions(-)

Index: linux-2.6.20-git16/drivers/net/spider_net.h
===================================================================
--- linux-2.6.20-git16.orig/drivers/net/spider_net.h 2007-02-20 15:02:42.000000000 -0600
+++ linux-2.6.20-git16/drivers/net/spider_net.h 2007-02-20 15:02:44.000000000 -0600
@@ -25,7 +25,7 @@
#ifndef _SPIDER_NET_H
#define _SPIDER_NET_H

-#define VERSION "1.6 B"
+#define VERSION "1.6 C"

#include "sungem_phy.h"

@@ -364,8 +364,8 @@ enum spider_net_int2_status {
#define SPIDER_NET_DESCR_NOT_IN_USE 0xF0000000
#define SPIDER_NET_DESCR_TXDESFLG 0x00800000

-struct spider_net_descr {
- /* as defined by the hardware */
+/* Descriptor, as defined by the hardware */
+struct spider_net_hw_descr {
u32 buf_addr;
u32 buf_size;
u32 next_descr_addr;
@@ -374,13 +374,15 @@ struct spider_net_descr {
u32 valid_size; /* all zeroes for tx */
u32 data_status;
u32 data_error; /* all zeroes for tx */
+} __attribute__((aligned(32)));

- /* used in the driver */
+struct spider_net_descr {
+ struct spider_net_hw_descr *hwdescr;
struct sk_buff *skb;
u32 bus_addr;
struct spider_net_descr *next;
struct spider_net_descr *prev;
-} __attribute__((aligned(32)));
+};

struct spider_net_descr_chain {
spinlock_t lock;
@@ -388,6 +390,7 @@ struct spider_net_descr_chain {
struct spider_net_descr *tail;
struct spider_net_descr *ring;
int num_desc;
+ struct spider_net_hw_descr *hwring;
dma_addr_t dma_addr;
};

@@ -464,6 +467,9 @@ struct spider_net_card {
struct net_device_stats netdev_stats;
struct spider_net_extra_stats spider_stats;
struct spider_net_options options;
+
+ /* Must be last item in struct */
+ struct spider_net_descr darray[0];
};

#define pr_err(fmt,arg...) \
Index: linux-2.6.20-git16/drivers/net/spider_net.c
===================================================================
--- linux-2.6.20-git16.orig/drivers/net/spider_net.c 2007-02-20 15:02:42.000000000 -0600
+++ linux-2.6.20-git16/drivers/net/spider_net.c 2007-02-20 15:02:44.000000000 -0600
@@ -299,9 +299,9 @@ spider_net_get_mac_address(struct net_de
* returns the status as in the dmac_cmd_status field of the descriptor
*/
static inline int
-spider_net_get_descr_status(struct spider_net_descr *descr)
+spider_net_get_descr_status(struct spider_net_hw_descr *hwdescr)
{
- return descr->dmac_cmd_status & SPIDER_NET_DESCR_IND_PROC_MASK;
+ return hwdescr->dmac_cmd_status & SPIDER_NET_DESCR_IND_PROC_MASK;
}

/**
@@ -319,12 +319,12 @@ spider_net_free_chain(struct spider_net_
descr = chain->ring;
do {
descr->bus_addr = 0;
- descr->next_descr_addr = 0;
+ descr->hwdescr->next_descr_addr = 0;
descr = descr->next;
} while (descr != chain->ring);

dma_free_coherent(&card->pdev->dev, chain->num_desc,
- chain->ring, chain->dma_addr);
+ chain->hwring, chain->dma_addr);
}

/**
@@ -343,31 +343,34 @@ spider_net_init_chain(struct spider_net_
{
int i;
struct spider_net_descr *descr;
+ struct spider_net_hw_descr *hwdescr;
dma_addr_t buf;
size_t alloc_size;

- alloc_size = chain->num_desc * sizeof (struct spider_net_descr);
+ alloc_size = chain->num_desc * sizeof(struct spider_net_hw_descr);

- chain->ring = dma_alloc_coherent(&card->pdev->dev, alloc_size,
+ chain->hwring = dma_alloc_coherent(&card->pdev->dev, alloc_size,
&chain->dma_addr, GFP_KERNEL);

- if (!chain->ring)
+ if (!chain->hwring)
return -ENOMEM;

- descr = chain->ring;
- memset(descr, 0, alloc_size);
+ memset(chain->ring, 0, chain->num_desc * sizeof(struct spider_net_descr));

/* Set up the hardware pointers in each descriptor */
+ descr = chain->ring;
+ hwdescr = chain->hwring;
buf = chain->dma_addr;
- for (i=0; i < chain->num_desc; i++, descr++) {
- descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
+ for (i=0; i < chain->num_desc; i++, descr++, hwdescr++) {
+ hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
+ hwdescr->next_descr_addr = 0;

+ descr->hwdescr = hwdescr;
descr->bus_addr = buf;
- descr->next_descr_addr = 0;
descr->next = descr + 1;
descr->prev = descr - 1;

- buf += sizeof(struct spider_net_descr);
+ buf += sizeof(struct spider_net_hw_descr);
}
/* do actual circular list */
(descr-1)->next = chain->ring;
@@ -394,7 +397,7 @@ spider_net_free_rx_chain_contents(struct
do {
if (descr->skb) {
dev_kfree_skb(descr->skb);
- pci_unmap_single(card->pdev, descr->buf_addr,
+ pci_unmap_single(card->pdev, descr->hwdescr->buf_addr,
SPIDER_NET_MAX_FRAME,
PCI_DMA_BIDIRECTIONAL);
}
@@ -416,6 +419,7 @@ static int
spider_net_prepare_rx_descr(struct spider_net_card *card,
struct spider_net_descr *descr)
{
+ struct spider_net_hw_descr *hwdescr = descr->hwdescr;
dma_addr_t buf;
int offset;
int bufsize;
@@ -434,11 +438,11 @@ spider_net_prepare_rx_descr(struct spide
card->spider_stats.alloc_rx_skb_error++;
return -ENOMEM;
}
- descr->buf_size = bufsize;
- descr->result_size = 0;
- descr->valid_size = 0;
- descr->data_status = 0;
- descr->data_error = 0;
+ hwdescr->buf_size = bufsize;
+ hwdescr->result_size = 0;
+ hwdescr->valid_size = 0;
+ hwdescr->data_status = 0;
+ hwdescr->data_error = 0;

offset = ((unsigned long)descr->skb->data) &
(SPIDER_NET_RXBUF_ALIGN - 1);
@@ -447,21 +451,21 @@ spider_net_prepare_rx_descr(struct spide
/* iommu-map the skb */
buf = pci_map_single(card->pdev, descr->skb->data,
SPIDER_NET_MAX_FRAME, PCI_DMA_FROMDEVICE);
- descr->buf_addr = buf;
if (pci_dma_mapping_error(buf)) {
dev_kfree_skb_any(descr->skb);
if (netif_msg_rx_err(card) && net_ratelimit())
pr_err("Could not iommu-map rx buffer\n");
card->spider_stats.rx_iommu_map_error++;
- descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
+ hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
} else {
- descr->next_descr_addr = 0;
+ hwdescr->buf_addr = buf;
+ hwdescr->next_descr_addr = 0;
wmb();
- descr->dmac_cmd_status = SPIDER_NET_DESCR_CARDOWNED |
+ hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_CARDOWNED |
SPIDER_NET_DMAC_NOINTR_COMPLETE;

wmb();
- descr->prev->next_descr_addr = descr->bus_addr;
+ descr->prev->hwdescr->next_descr_addr = descr->bus_addr;
}

return 0;
@@ -517,7 +521,7 @@ spider_net_refill_rx_chain(struct spider
if (!spin_trylock_irqsave(&chain->lock, flags))
return;

- while (spider_net_get_descr_status(chain->head) ==
+ while (spider_net_get_descr_status(chain->head->hwdescr) ==
SPIDER_NET_DESCR_NOT_IN_USE) {
if (spider_net_prepare_rx_descr(card, chain->head))
break;
@@ -679,6 +683,7 @@ spider_net_prepare_tx_descr(struct spide
struct sk_buff *skb)
{
struct spider_net_descr *descr;
+ struct spider_net_hw_descr *hwdescr;
dma_addr_t buf;
unsigned long flags;

@@ -693,30 +698,32 @@ spider_net_prepare_tx_descr(struct spide

spin_lock_irqsave(&card->tx_chain.lock, flags);
descr = card->tx_chain.head;
+ hwdescr = descr->hwdescr;
card->tx_chain.head = descr->next;

- descr->buf_addr = buf;
- descr->buf_size = skb->len;
- descr->next_descr_addr = 0;
descr->skb = skb;
- descr->data_status = 0;
+ hwdescr->buf_addr = buf;
+ hwdescr->buf_size = skb->len;
+ hwdescr->next_descr_addr = 0;
+ hwdescr->data_status = 0;

- descr->dmac_cmd_status =
+ hwdescr->dmac_cmd_status =
SPIDER_NET_DESCR_CARDOWNED | SPIDER_NET_DMAC_NOCS;
spin_unlock_irqrestore(&card->tx_chain.lock, flags);

if (skb->protocol == htons(ETH_P_IP))
switch (skb->nh.iph->protocol) {
case IPPROTO_TCP:
- descr->dmac_cmd_status |= SPIDER_NET_DMAC_TCP;
+ hwdescr->dmac_cmd_status |= SPIDER_NET_DMAC_TCP;
break;
case IPPROTO_UDP:
- descr->dmac_cmd_status |= SPIDER_NET_DMAC_UDP;
+ hwdescr->dmac_cmd_status |= SPIDER_NET_DMAC_UDP;
break;
}

/* Chain the bus address, so that the DMA engine finds this descr. */
- descr->prev->next_descr_addr = descr->bus_addr;
+ wmb();
+ descr->prev->hwdescr->next_descr_addr = descr->bus_addr;

card->netdev->trans_start = jiffies; /* set netdev watchdog timer */
return 0;
@@ -725,16 +732,17 @@ spider_net_prepare_tx_descr(struct spide
static int
spider_net_set_low_watermark(struct spider_net_card *card)
{
+ struct spider_net_descr *descr = card->tx_chain.tail;
+ struct spider_net_hw_descr *hwdescr;
unsigned long flags;
int status;
int cnt=0;
int i;
- struct spider_net_descr *descr = card->tx_chain.tail;

/* Measure the length of the queue. Measurement does not
* need to be precise -- does not need a lock. */
while (descr != card->tx_chain.head) {
- status = descr->dmac_cmd_status & SPIDER_NET_DESCR_NOT_IN_USE;
+ status = descr->hwdescr->dmac_cmd_status & SPIDER_NET_DESCR_NOT_IN_USE;
if (status == SPIDER_NET_DESCR_NOT_IN_USE)
break;
descr = descr->next;
@@ -753,10 +761,12 @@ spider_net_set_low_watermark(struct spid

/* Set the new watermark, clear the old watermark */
spin_lock_irqsave(&card->tx_chain.lock, flags);
- descr->dmac_cmd_status |= SPIDER_NET_DESCR_TXDESFLG;
- if (card->low_watermark && card->low_watermark != descr)
- card->low_watermark->dmac_cmd_status =
- card->low_watermark->dmac_cmd_status & ~SPIDER_NET_DESCR_TXDESFLG;
+ descr->hwdescr->dmac_cmd_status |= SPIDER_NET_DESCR_TXDESFLG;
+ if (card->low_watermark && card->low_watermark != descr) {
+ hwdescr = card->low_watermark->hwdescr;
+ hwdescr->dmac_cmd_status =
+ hwdescr->dmac_cmd_status & ~SPIDER_NET_DESCR_TXDESFLG;
+ }
card->low_watermark = descr;
spin_unlock_irqrestore(&card->tx_chain.lock, flags);
return cnt;
@@ -779,6 +789,7 @@ spider_net_release_tx_chain(struct spide
{
struct spider_net_descr_chain *chain = &card->tx_chain;
struct spider_net_descr *descr;
+ struct spider_net_hw_descr *hwdescr;
struct sk_buff *skb;
u32 buf_addr;
unsigned long flags;
@@ -787,8 +798,9 @@ spider_net_release_tx_chain(struct spide
while (chain->tail != chain->head) {
spin_lock_irqsave(&chain->lock, flags);
descr = chain->tail;
+ hwdescr = descr->hwdescr;

- status = spider_net_get_descr_status(descr);
+ status = spider_net_get_descr_status(hwdescr);
switch (status) {
case SPIDER_NET_DESCR_COMPLETE:
card->netdev_stats.tx_packets++;
@@ -824,9 +836,9 @@ spider_net_release_tx_chain(struct spide
}

chain->tail = descr->next;
- descr->dmac_cmd_status |= SPIDER_NET_DESCR_NOT_IN_USE;
+ hwdescr->dmac_cmd_status |= SPIDER_NET_DESCR_NOT_IN_USE;
skb = descr->skb;
- buf_addr = descr->buf_addr;
+ buf_addr = hwdescr->buf_addr;
spin_unlock_irqrestore(&chain->lock, flags);

/* unmap the skb */
@@ -862,7 +874,7 @@ spider_net_kick_tx_dma(struct spider_net

descr = card->tx_chain.tail;
for (;;) {
- if (spider_net_get_descr_status(descr) ==
+ if (spider_net_get_descr_status(descr->hwdescr) ==
SPIDER_NET_DESCR_CARDOWNED) {
spider_net_write_reg(card, SPIDER_NET_GDTDCHA,
descr->bus_addr);
@@ -958,17 +970,18 @@ static void
spider_net_pass_skb_up(struct spider_net_descr *descr,
struct spider_net_card *card)
{
+ struct spider_net_hw_descr *hwdescr= descr->hwdescr;
struct sk_buff *skb;
struct net_device *netdev;
u32 data_status, data_error;

- data_status = descr->data_status;
- data_error = descr->data_error;
+ data_status = hwdescr->data_status;
+ data_error = hwdescr->data_error;
netdev = card->netdev;

skb = descr->skb;
skb->dev = netdev;
- skb_put(skb, descr->valid_size);
+ skb_put(skb, hwdescr->valid_size);

/* the card seems to add 2 bytes of junk in front
* of the ethernet frame */
@@ -1044,9 +1057,10 @@ spider_net_decode_one_descr(struct spide
{
struct spider_net_descr_chain *chain = &card->rx_chain;
struct spider_net_descr *descr = chain->tail;
+ struct spider_net_hw_descr *hwdescr = descr->hwdescr;
int status;

- status = spider_net_get_descr_status(descr);
+ status = spider_net_get_descr_status(hwdescr);

/* Nothing in the descriptor, or ring must be empty */
if ((status == SPIDER_NET_DESCR_CARDOWNED) ||
@@ -1057,7 +1071,7 @@ spider_net_decode_one_descr(struct spide
chain->tail = descr->next;

/* unmap descriptor */
- pci_unmap_single(card->pdev, descr->buf_addr,
+ pci_unmap_single(card->pdev, hwdescr->buf_addr,
SPIDER_NET_MAX_FRAME, PCI_DMA_FROMDEVICE);

if ( (status == SPIDER_NET_DESCR_RESPONSE_ERROR) ||
@@ -1080,27 +1094,26 @@ spider_net_decode_one_descr(struct spide
}

/* The cases we'll throw away the packet immediately */
- if (descr->data_error & SPIDER_NET_DESTROY_RX_FLAGS) {
+ if (hwdescr->data_error & SPIDER_NET_DESTROY_RX_FLAGS) {
if (netif_msg_rx_err(card))
pr_err("%s: error in received descriptor found, "
"data_status=x%08x, data_error=x%08x\n",
card->netdev->name,
- descr->data_status, descr->data_error);
+ hwdescr->data_status, hwdescr->data_error);
goto bad_desc;
}

- if (descr->dmac_cmd_status & 0xfefe) {
+ if (hwdescr->dmac_cmd_status & 0xfefe) {
pr_err("%s: bad status, cmd_status=x%08x\n",
card->netdev->name,
- descr->dmac_cmd_status);
- pr_err("buf_addr=x%08x\n", descr->buf_addr);
- pr_err("buf_size=x%08x\n", descr->buf_size);
- pr_err("next_descr_addr=x%08x\n", descr->next_descr_addr);
- pr_err("result_size=x%08x\n", descr->result_size);
- pr_err("valid_size=x%08x\n", descr->valid_size);
- pr_err("data_status=x%08x\n", descr->data_status);
- pr_err("data_error=x%08x\n", descr->data_error);
- pr_err("bus_addr=x%08x\n", descr->bus_addr);
+ hwdescr->dmac_cmd_status);
+ pr_err("buf_addr=x%08x\n", hwdescr->buf_addr);
+ pr_err("buf_size=x%08x\n", hwdescr->buf_size);
+ pr_err("next_descr_addr=x%08x\n", hwdescr->next_descr_addr);
+ pr_err("result_size=x%08x\n", hwdescr->result_size);
+ pr_err("valid_size=x%08x\n", hwdescr->valid_size);
+ pr_err("data_status=x%08x\n", hwdescr->data_status);
+ pr_err("data_error=x%08x\n", hwdescr->data_error);
pr_err("which=%ld\n", descr - card->rx_chain.ring);

card->spider_stats.rx_desc_error++;
@@ -1109,12 +1122,12 @@ spider_net_decode_one_descr(struct spide

/* Ok, we've got a packet in descr */
spider_net_pass_skb_up(descr, card);
- descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
+ hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
return 1;

bad_desc:
dev_kfree_skb_irq(descr->skb);
- descr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
+ hwdescr->dmac_cmd_status = SPIDER_NET_DESCR_NOT_IN_USE;
return 0;
}

@@ -2200,9 +2213,6 @@ spider_net_setup_netdev(struct spider_ne

card->options.rx_csum = SPIDER_NET_RX_CSUM_DEFAULT;

- card->tx_chain.num_desc = tx_descriptors;
- card->rx_chain.num_desc = rx_descriptors;
-
spider_net_setup_netdev_ops(netdev);

netdev->features = NETIF_F_HW_CSUM | NETIF_F_LLTX;
@@ -2250,8 +2260,11 @@ spider_net_alloc_card(void)
{
struct net_device *netdev;
struct spider_net_card *card;
+ size_t alloc_size;

- netdev = alloc_etherdev(sizeof(struct spider_net_card));
+ alloc_size = sizeof(struct spider_net_card) +
+ (tx_descriptors + rx_descriptors) * sizeof(struct spider_net_descr);
+ netdev = alloc_etherdev(alloc_size);
if (!netdev)
return NULL;

@@ -2262,6 +2275,11 @@ spider_net_alloc_card(void)
init_waitqueue_head(&card->waitq);
atomic_set(&card->tx_timeout_task_counter, 0);

+ card->rx_chain.num_desc = rx_descriptors;
+ card->rx_chain.ring = card->darray;
+ card->tx_chain.num_desc = tx_descriptors;
+ card->tx_chain.ring = card->darray + rx_descriptors;
+
return card;
}

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