ibmveth: enable driver for CMO

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>

2 files changed, 140 insertions, 34 deletions

diff --git a/drivers/net/ibmveth.c b/drivers/net/ibmveth.c
index 007ca8735a94..e5a6e2e84540 100644
--- a/drivers/net/ibmveth.c
+++ b/drivers/net/ibmveth.c
@@ -33,6 +33,7 @@
 */
 
 #include <linux/module.h>
+#include <linux/moduleparam.h>
 #include <linux/types.h>
 #include <linux/errno.h>
 #include <linux/ioport.h>
@@ -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"
@@ -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;
@@ -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);
 
@@ -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;
@@ -267,20 +275,9 @@ 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++;
                 }
@@ -288,6 +285,24 @@ static void ibmveth_replenish_buffer_pool(struct ibmveth_adapter *adapter, struc
 
         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));
 }
 
 /* replenish routine */
@@ -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]);
@@ -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,
@@ -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);
 
@@ -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)) {
@@ -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;
@@ -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;
@@ -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;
@@ -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;
                 }
         }
@@ -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;
@@ -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;
 }
 
@@ -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,
diff --git a/drivers/net/ibmveth.h b/drivers/net/ibmveth.h
index 41f61cd18852..d28186948752 100644
--- a/drivers/net/ibmveth.h
+++ b/drivers/net/ibmveth.h
@@ -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 };
@@ -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;