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ibmveth: enable driver for CMO
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Enable ibmveth for Cooperative Memory Overcommitment (CMO).  For this driver
it means calculating a desired amount of IO memory based on the current MTU
and updating this value with the bus when MTU changes occur.  Because DMA
mappings can fail, we have added a bounce buffer for temporary cases where
the driver can not map IO memory for the buffer pool.

The following changes are made to enable the driver for CMO:
 * DMA mapping errors will not result in error messages if entitlement has
   been exceeded and resources were not available.
 * DMA mapping errors are handled gracefully, ibmveth_replenish_buffer_pool()
   is corrected to check the return from dma_map_single and fail gracefully.
 * The driver will have a get_desired_dma function defined to function
   in a CMO environment.
 * When the MTU is changed, the driver will update the device IO entitlement

Signed-off-by: Robert Jennings <rcj@linux.vnet.ibm.com>
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Santiago Leon <santil@us.ibm.com>
Acked-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
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Robert Jennings authored and Benjamin Herrenschmidt committed Jul 25, 2008
1 parent ea866e6 commit 1096d63
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Showing 2 changed files with 140 additions and 34 deletions.
169 changes: 135 additions & 34 deletions drivers/net/ibmveth.c
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,7 @@
*/

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/ioport.h>
Expand All @@ -52,7 +53,9 @@
#include <asm/hvcall.h>
#include <asm/atomic.h>
#include <asm/vio.h>
#include <asm/iommu.h>
#include <asm/uaccess.h>
#include <asm/firmware.h>
#include <linux/seq_file.h>

#include "ibmveth.h"
Expand Down Expand Up @@ -94,8 +97,10 @@ static void ibmveth_proc_register_adapter(struct ibmveth_adapter *adapter);
static void ibmveth_proc_unregister_adapter(struct ibmveth_adapter *adapter);
static irqreturn_t ibmveth_interrupt(int irq, void *dev_instance);
static void ibmveth_rxq_harvest_buffer(struct ibmveth_adapter *adapter);
static unsigned long ibmveth_get_desired_dma(struct vio_dev *vdev);
static struct kobj_type ktype_veth_pool;


#ifdef CONFIG_PROC_FS
#define IBMVETH_PROC_DIR "ibmveth"
static struct proc_dir_entry *ibmveth_proc_dir;
Expand Down Expand Up @@ -226,16 +231,16 @@ static void ibmveth_replenish_buffer_pool(struct ibmveth_adapter *adapter, struc
u32 i;
u32 count = pool->size - atomic_read(&pool->available);
u32 buffers_added = 0;
struct sk_buff *skb;
unsigned int free_index, index;
u64 correlator;
unsigned long lpar_rc;
dma_addr_t dma_addr;

mb();

for(i = 0; i < count; ++i) {
struct sk_buff *skb;
unsigned int free_index, index;
u64 correlator;
union ibmveth_buf_desc desc;
unsigned long lpar_rc;
dma_addr_t dma_addr;

skb = alloc_skb(pool->buff_size, GFP_ATOMIC);

Expand All @@ -255,6 +260,9 @@ static void ibmveth_replenish_buffer_pool(struct ibmveth_adapter *adapter, struc
dma_addr = dma_map_single(&adapter->vdev->dev, skb->data,
pool->buff_size, DMA_FROM_DEVICE);

if (dma_mapping_error(dma_addr))
goto failure;

pool->free_map[free_index] = IBM_VETH_INVALID_MAP;
pool->dma_addr[index] = dma_addr;
pool->skbuff[index] = skb;
Expand All @@ -267,25 +275,32 @@ static void ibmveth_replenish_buffer_pool(struct ibmveth_adapter *adapter, struc

lpar_rc = h_add_logical_lan_buffer(adapter->vdev->unit_address, desc.desc);

if(lpar_rc != H_SUCCESS) {
pool->free_map[free_index] = index;
pool->skbuff[index] = NULL;
if (pool->consumer_index == 0)
pool->consumer_index = pool->size - 1;
else
pool->consumer_index--;
dma_unmap_single(&adapter->vdev->dev,
pool->dma_addr[index], pool->buff_size,
DMA_FROM_DEVICE);
dev_kfree_skb_any(skb);
adapter->replenish_add_buff_failure++;
break;
} else {
if (lpar_rc != H_SUCCESS)
goto failure;
else {
buffers_added++;
adapter->replenish_add_buff_success++;
}
}

mb();
atomic_add(buffers_added, &(pool->available));
return;

failure:
pool->free_map[free_index] = index;
pool->skbuff[index] = NULL;
if (pool->consumer_index == 0)
pool->consumer_index = pool->size - 1;
else
pool->consumer_index--;
if (!dma_mapping_error(dma_addr))
dma_unmap_single(&adapter->vdev->dev,
pool->dma_addr[index], pool->buff_size,
DMA_FROM_DEVICE);
dev_kfree_skb_any(skb);
adapter->replenish_add_buff_failure++;

mb();
atomic_add(buffers_added, &(pool->available));
}
Expand All @@ -297,7 +312,7 @@ static void ibmveth_replenish_task(struct ibmveth_adapter *adapter)

adapter->replenish_task_cycles++;

for(i = 0; i < IbmVethNumBufferPools; i++)
for (i = (IbmVethNumBufferPools - 1); i >= 0; i--)
if(adapter->rx_buff_pool[i].active)
ibmveth_replenish_buffer_pool(adapter,
&adapter->rx_buff_pool[i]);
Expand Down Expand Up @@ -472,6 +487,18 @@ static void ibmveth_cleanup(struct ibmveth_adapter *adapter)
if (adapter->rx_buff_pool[i].active)
ibmveth_free_buffer_pool(adapter,
&adapter->rx_buff_pool[i]);

if (adapter->bounce_buffer != NULL) {
if (!dma_mapping_error(adapter->bounce_buffer_dma)) {
dma_unmap_single(&adapter->vdev->dev,
adapter->bounce_buffer_dma,
adapter->netdev->mtu + IBMVETH_BUFF_OH,
DMA_BIDIRECTIONAL);
adapter->bounce_buffer_dma = DMA_ERROR_CODE;
}
kfree(adapter->bounce_buffer);
adapter->bounce_buffer = NULL;
}
}

static int ibmveth_register_logical_lan(struct ibmveth_adapter *adapter,
Expand Down Expand Up @@ -607,6 +634,24 @@ static int ibmveth_open(struct net_device *netdev)
return rc;
}

adapter->bounce_buffer =
kmalloc(netdev->mtu + IBMVETH_BUFF_OH, GFP_KERNEL);
if (!adapter->bounce_buffer) {
ibmveth_error_printk("unable to allocate bounce buffer\n");
ibmveth_cleanup(adapter);
napi_disable(&adapter->napi);
return -ENOMEM;
}
adapter->bounce_buffer_dma =
dma_map_single(&adapter->vdev->dev, adapter->bounce_buffer,
netdev->mtu + IBMVETH_BUFF_OH, DMA_BIDIRECTIONAL);
if (dma_mapping_error(adapter->bounce_buffer_dma)) {
ibmveth_error_printk("unable to map bounce buffer\n");
ibmveth_cleanup(adapter);
napi_disable(&adapter->napi);
return -ENOMEM;
}

ibmveth_debug_printk("initial replenish cycle\n");
ibmveth_interrupt(netdev->irq, netdev);

Expand Down Expand Up @@ -853,10 +898,12 @@ static int ibmveth_start_xmit(struct sk_buff *skb, struct net_device *netdev)
unsigned int tx_packets = 0;
unsigned int tx_send_failed = 0;
unsigned int tx_map_failed = 0;
int used_bounce = 0;
unsigned long data_dma_addr;

desc.fields.flags_len = IBMVETH_BUF_VALID | skb->len;
desc.fields.address = dma_map_single(&adapter->vdev->dev, skb->data,
skb->len, DMA_TO_DEVICE);
data_dma_addr = dma_map_single(&adapter->vdev->dev, skb->data,
skb->len, DMA_TO_DEVICE);

if (skb->ip_summed == CHECKSUM_PARTIAL &&
ip_hdr(skb)->protocol != IPPROTO_TCP && skb_checksum_help(skb)) {
Expand All @@ -875,12 +922,16 @@ static int ibmveth_start_xmit(struct sk_buff *skb, struct net_device *netdev)
buf[1] = 0;
}

if (dma_mapping_error(desc.fields.address)) {
ibmveth_error_printk("tx: unable to map xmit buffer\n");
if (dma_mapping_error(data_dma_addr)) {
if (!firmware_has_feature(FW_FEATURE_CMO))
ibmveth_error_printk("tx: unable to map xmit buffer\n");
skb_copy_from_linear_data(skb, adapter->bounce_buffer,
skb->len);
desc.fields.address = adapter->bounce_buffer_dma;
tx_map_failed++;
tx_dropped++;
goto out;
}
used_bounce = 1;
} else
desc.fields.address = data_dma_addr;

/* send the frame. Arbitrarily set retrycount to 1024 */
correlator = 0;
Expand All @@ -904,8 +955,9 @@ static int ibmveth_start_xmit(struct sk_buff *skb, struct net_device *netdev)
netdev->trans_start = jiffies;
}

dma_unmap_single(&adapter->vdev->dev, desc.fields.address,
skb->len, DMA_TO_DEVICE);
if (!used_bounce)
dma_unmap_single(&adapter->vdev->dev, data_dma_addr,
skb->len, DMA_TO_DEVICE);

out: spin_lock_irqsave(&adapter->stats_lock, flags);
netdev->stats.tx_dropped += tx_dropped;
Expand Down Expand Up @@ -1053,8 +1105,9 @@ static void ibmveth_set_multicast_list(struct net_device *netdev)
static int ibmveth_change_mtu(struct net_device *dev, int new_mtu)
{
struct ibmveth_adapter *adapter = dev->priv;
struct vio_dev *viodev = adapter->vdev;
int new_mtu_oh = new_mtu + IBMVETH_BUFF_OH;
int i, rc;
int i;

if (new_mtu < IBMVETH_MAX_MTU)
return -EINVAL;
Expand Down Expand Up @@ -1085,10 +1138,15 @@ static int ibmveth_change_mtu(struct net_device *dev, int new_mtu)
ibmveth_close(adapter->netdev);
adapter->pool_config = 0;
dev->mtu = new_mtu;
if ((rc = ibmveth_open(adapter->netdev)))
return rc;
} else
dev->mtu = new_mtu;
vio_cmo_set_dev_desired(viodev,
ibmveth_get_desired_dma
(viodev));
return ibmveth_open(adapter->netdev);
}
dev->mtu = new_mtu;
vio_cmo_set_dev_desired(viodev,
ibmveth_get_desired_dma
(viodev));
return 0;
}
}
Expand All @@ -1103,6 +1161,46 @@ static void ibmveth_poll_controller(struct net_device *dev)
}
#endif

/**
* ibmveth_get_desired_dma - Calculate IO memory desired by the driver
*
* @vdev: struct vio_dev for the device whose desired IO mem is to be returned
*
* Return value:
* Number of bytes of IO data the driver will need to perform well.
*/
static unsigned long ibmveth_get_desired_dma(struct vio_dev *vdev)
{
struct net_device *netdev = dev_get_drvdata(&vdev->dev);
struct ibmveth_adapter *adapter;
unsigned long ret;
int i;
int rxqentries = 1;

/* netdev inits at probe time along with the structures we need below*/
if (netdev == NULL)
return IOMMU_PAGE_ALIGN(IBMVETH_IO_ENTITLEMENT_DEFAULT);

adapter = netdev_priv(netdev);

ret = IBMVETH_BUFF_LIST_SIZE + IBMVETH_FILT_LIST_SIZE;
ret += IOMMU_PAGE_ALIGN(netdev->mtu);

for (i = 0; i < IbmVethNumBufferPools; i++) {
/* add the size of the active receive buffers */
if (adapter->rx_buff_pool[i].active)
ret +=
adapter->rx_buff_pool[i].size *
IOMMU_PAGE_ALIGN(adapter->rx_buff_pool[i].
buff_size);
rxqentries += adapter->rx_buff_pool[i].size;
}
/* add the size of the receive queue entries */
ret += IOMMU_PAGE_ALIGN(rxqentries * sizeof(struct ibmveth_rx_q_entry));

return ret;
}

static int __devinit ibmveth_probe(struct vio_dev *dev, const struct vio_device_id *id)
{
int rc, i;
Expand Down Expand Up @@ -1247,6 +1345,8 @@ static int __devexit ibmveth_remove(struct vio_dev *dev)
ibmveth_proc_unregister_adapter(adapter);

free_netdev(netdev);
dev_set_drvdata(&dev->dev, NULL);

return 0;
}

Expand Down Expand Up @@ -1491,6 +1591,7 @@ static struct vio_driver ibmveth_driver = {
.id_table = ibmveth_device_table,
.probe = ibmveth_probe,
.remove = ibmveth_remove,
.get_desired_dma = ibmveth_get_desired_dma,
.driver = {
.name = ibmveth_driver_name,
.owner = THIS_MODULE,
Expand Down
5 changes: 5 additions & 0 deletions drivers/net/ibmveth.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -93,9 +93,12 @@ static inline long h_illan_attributes(unsigned long unit_address,
plpar_hcall_norets(H_CHANGE_LOGICAL_LAN_MAC, ua, mac)

#define IbmVethNumBufferPools 5
#define IBMVETH_IO_ENTITLEMENT_DEFAULT 4243456 /* MTU of 1500 needs 4.2Mb */
#define IBMVETH_BUFF_OH 22 /* Overhead: 14 ethernet header + 8 opaque handle */
#define IBMVETH_MAX_MTU 68
#define IBMVETH_MAX_POOL_COUNT 4096
#define IBMVETH_BUFF_LIST_SIZE 4096
#define IBMVETH_FILT_LIST_SIZE 4096
#define IBMVETH_MAX_BUF_SIZE (1024 * 128)

static int pool_size[] = { 512, 1024 * 2, 1024 * 16, 1024 * 32, 1024 * 64 };
Expand Down Expand Up @@ -143,6 +146,8 @@ struct ibmveth_adapter {
struct ibmveth_rx_q rx_queue;
int pool_config;
int rx_csum;
void *bounce_buffer;
dma_addr_t bounce_buffer_dma;

/* adapter specific stats */
u64 replenish_task_cycles;
Expand Down

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