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Message-ID: <20150724053058.GC2178@nanopsycho.orion>
Date: Fri, 24 Jul 2015 07:30:58 +0200
From: Jiri Pirko <jiri@...nulli.us>
To: Scott Feldman <sfeldma@...il.com>
Cc: Netdev <netdev@...r.kernel.org>,
"David S. Miller" <davem@...emloft.net>, idosch@...lanox.com,
eladr@...lanox.com,
"ogerlitz@...lanox.com" <ogerlitz@...lanox.com>,
Roopa Prabhu <roopa@...ulusnetworks.com>,
Florian Fainelli <f.fainelli@...il.com>,
Thomas Graf <tgraf@...g.ch>, ast@...mgrid.com,
Jamal Hadi Salim <jhs@...atatu.com>,
Daniel Borkmann <daniel@...earbox.net>,
john fastabend <john.fastabend@...il.com>,
"simon.horman@...ronome.com" <simon.horman@...ronome.com>,
John Linville <linville@...driver.com>,
Andy Gospodarek <andy@...yhouse.net>,
Shrijeet Mukherjee <shm@...ulusnetworks.com>,
"nhorman@...driver.com" <nhorman@...driver.com>,
Jiri Pirko <jiri@...lanox.com>
Subject: Re: [patch net-next 2/4] mlxsw: Add PCI bus implementation
Fri, Jul 24, 2015 at 06:52:16AM CEST, sfeldma@...il.com wrote:
>On Thu, Jul 23, 2015 at 8:43 AM, Jiri Pirko <jiri@...nulli.us> wrote:
>> From: Jiri Pirko <jiri@...lanox.com>
>>
>> Add PCI bus implementation for Mellanox Technologies Switch ASICs. This
>> includes firmware initialization, async queues manipulation and command
>> interface implementation.
>>
>> Signed-off-by: Jiri Pirko <jiri@...lanox.com>
>> Signed-off-by: Ido Schimmel <idosch@...lanox.com>
>> Signed-off-by: Elad Raz <eladr@...lanox.com>
>
>[cut]
>
>> +static int mlxsw_pci_skb_transmit(void *bus_priv, struct sk_buff *skb,
>> + const struct mlxsw_tx_info *tx_info)
>> +{
>> + struct mlxsw_pci *mlxsw_pci = bus_priv;
>> + struct mlxsw_pci_queue *q;
>> + struct mlxsw_pci_queue_elem_info *elem_info;
>> + char *wqe;
>> + int i;
>> + int err;
>> +
>> + if (skb_shinfo(skb)->nr_frags > MLXSW_PCI_WQE_SG_ENTRIES - 1)
>> + return -EINVAL;
>
>Can you skb_linearize() here to try to continue?
Sure, I think we can do it. This would be good to have in rocker too.
>
>> + q = mlxsw_pci_sdq_pick(mlxsw_pci, tx_info);
>> + spin_lock_bh(&q->lock);
>> + elem_info = mlxsw_pci_queue_elem_info_producer_get(q);
>> + if (!elem_info) {
>> + /* queue is full */
>> + err = -EAGAIN;
>> + goto unlock;
>> + }
>> + elem_info->u.sdq.skb = skb;
>> +
>> + wqe = elem_info->elem;
>> + mlxsw_pci_wqe_c_set(wqe, 1); /* always report completion */
>> + mlxsw_pci_wqe_lp_set(wqe, !!tx_info->is_emad);
>> + mlxsw_pci_wqe_type_set(wqe, MLXSW_PCI_WQE_TYPE_ETHERNET);
>> +
>> + err = mlxsw_pci_wqe_frag_map(mlxsw_pci, wqe, 0, skb->data,
>> + skb_headlen(skb), DMA_TO_DEVICE);
>> + if (err)
>> + goto unlock;
>> +
>> + for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
>> + const skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
>> +
>> + err = mlxsw_pci_wqe_frag_map(mlxsw_pci, wqe, i + 1,
>> + skb_frag_address(frag),
>> + skb_frag_size(frag),
>> + DMA_TO_DEVICE);
>> + if (err)
>> + goto unmap_frags;
>> + }
>> +
>> + /* Set unused sq entries byte count to zero. */
>> + for (i++; i < MLXSW_PCI_WQE_SG_ENTRIES; i++)
>> + mlxsw_pci_wqe_byte_count_set(wqe, i, 0);
>
>Is hw OK with not clearing the unused sq entries dma_address? Setting
>byte_count to zero must be sufficient?
Yes, byte_count == 0 is sufficient. No need to set address.
>
>> +
>> + /* Everything is set up, ring producer doorbell to get HW going */
>> + q->producer_counter++;
>> + mlxsw_pci_queue_doorbell_producer_ring(mlxsw_pci, q);
>> +
>> + goto unlock;
>> +
>> +unmap_frags:
>> + for (; i >= 0; i--)
>> + mlxsw_pci_wqe_frag_unmap(mlxsw_pci, wqe, i, DMA_TO_DEVICE);
>> +unlock:
>> + spin_unlock_bh(&q->lock);
>> + return err;
>> +}
>> +
>> +static int mlxsw_pci_cmd_exec(void *bus_priv, u16 opcode, u8 opcode_mod,
>> + u32 in_mod, bool out_mbox_direct,
>> + char *in_mbox, size_t in_mbox_size,
>> + char *out_mbox, size_t out_mbox_size,
>> + u8 *p_status)
>> +{
>> + struct mlxsw_pci *mlxsw_pci = bus_priv;
>> + dma_addr_t in_mapaddr = 0;
>> + dma_addr_t out_mapaddr = 0;
>> + bool evreq = mlxsw_pci->cmd.nopoll;
>> + unsigned long timeout = msecs_to_jiffies(MLXSW_PCI_CIR_TIMEOUT_MSECS);
>> + bool *p_wait_done = &mlxsw_pci->cmd.wait_done;
>
>Why is this initialized and then later set to false?
*p_wait_done
so we actually set not p_wait_done but mlxsw_pci->cmd.wait_done there.
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