Re: [PATCH] stmmac: enable rx queues

Joao Pinto
2016-12-20T15:09:46Z

Às 3:05 PM de 12/20/2016, Niklas Cassel escreveu:
>
>
> On 12/20/2016 03:52 PM, Joao Pinto wrote:
>> Hi Niklas,
>>
>> Às 2:43 PM de 12/20/2016, Niklas Cassel escreveu:
>>>
>>> On 12/20/2016 01:55 PM, Joao Pinto wrote:
>>>> When the hardware is synthesized with multiple queues, all queues are
>>>> disabled for default. This patch adds the rx queues configuration.
>>>> This patch was successfully tested in a Synopsys QoS Reference design.
>>>>
>>>> Signed-off-by: Joao Pinto <jpinto@synopsys.com>
>>>> ---
>>>> drivers/net/ethernet/stmicro/stmmac/common.h | 2 ++
>>>> drivers/net/ethernet/stmicro/stmmac/dwmac4.h | 4 ++++
>>>> drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c | 11 +++++++++++
>>>> drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 21 +++++++++++++++++++++
>>>> 4 files changed, 38 insertions(+)
>>>>
>>>> diff --git a/drivers/net/ethernet/stmicro/stmmac/common.h b/drivers/net/ethernet/stmicro/stmmac/common.h
>>>> index b13a144..61bab50 100644
>>>> --- a/drivers/net/ethernet/stmicro/stmmac/common.h
>>>> +++ b/drivers/net/ethernet/stmicro/stmmac/common.h
>>>> @@ -454,6 +454,8 @@ struct stmmac_ops {
>>>> void (*core_init)(struct mac_device_info *hw, int mtu);
>>>> /* Enable and verify that the IPC module is supported */
>>>> int (*rx_ipc)(struct mac_device_info *hw);
>>>> + /* Enable RX Queues */
>>>> + void (*rx_queue_enable)(struct mac_device_info *hw, u32 queue);
>>>> /* Dump MAC registers */
>>>> void (*dump_regs)(struct mac_device_info *hw);
>>>> /* Handle extra events on specific interrupts hw dependent */
>>>> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4.h b/drivers/net/ethernet/stmicro/stmmac/dwmac4.h
>>>> index 3e8d4fe..fd013bd 100644
>>>> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4.h
>>>> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4.h
>>>> @@ -22,6 +22,7 @@
>>>> #define GMAC_HASH_TAB_32_63 0x00000014
>>>> #define GMAC_RX_FLOW_CTRL 0x00000090
>>>> #define GMAC_QX_TX_FLOW_CTRL(x) (0x70 + x * 4)
>>>> +#define GMAC_RXQ_CTRL0 0x000000a0
>>>> #define GMAC_INT_STATUS 0x000000b0
>>>> #define GMAC_INT_EN 0x000000b4
>>>> #define GMAC_PCS_BASE 0x000000e0
>>>> @@ -44,6 +45,9 @@
>>>>
>>>> #define GMAC_MAX_PERFECT_ADDRESSES 128
>>>>
>>>> +/* MAC RX Queue Enable*/
>>>> +#define GMAC_RX_QUEUE_ENABLE(queue) BIT(queue * 2)
>>> Always have parentheses around a variable in a
>>> macro, otherwise strange things could happen.
>>> Imagine if you send 5 - 4 as argument,
>>> it will then expand to 5 - 4 * 2 = -3,
>>> instead of (5 - 4) * 2 = 2
>> Right. I am going to do that.
>>
>>>> +
>>>> /* MAC Flow Control RX */
>>>> #define GMAC_RX_FLOW_CTRL_RFE BIT(0)
>>>>
>>>> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
>>>> index eaed7cb..7ec1887 100644
>>>> --- a/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
>>>> +++ b/drivers/net/ethernet/stmicro/stmmac/dwmac4_core.c
>>>> @@ -59,6 +59,16 @@ static void dwmac4_core_init(struct mac_device_info *hw, int mtu)
>>>> writel(value, ioaddr + GMAC_INT_EN);
>>>> }
>>>>
>>>> +static void dwmac4_rx_queue_enable(struct mac_device_info *hw, u32 queue)
>>>> +{
>>>> + void __iomem *ioaddr = hw->pcsr;
>>>> + u32 value = readl(ioaddr + GMAC_RXQ_CTRL0);
>>>> +
>>>> + value |= GMAC_RX_QUEUE_ENABLE(queue);
>>>> +
>>>> + writel(value, ioaddr + GMAC_RXQ_CTRL0);
>>>> +}
>>>> +
>>>> static void dwmac4_dump_regs(struct mac_device_info *hw)
>>>> {
>>>> void __iomem *ioaddr = hw->pcsr;
>>>> @@ -392,6 +402,7 @@ static void dwmac4_debug(void __iomem *ioaddr, struct stmmac_extra_stats *x)
>>>> static const struct stmmac_ops dwmac4_ops = {
>>>> .core_init = dwmac4_core_init,
>>>> .rx_ipc = dwmac4_rx_ipc_enable,
>>>> + .rx_queue_enable = dwmac4_rx_queue_enable,
>>>> .dump_regs = dwmac4_dump_regs,
>>>> .host_irq_status = dwmac4_irq_status,
>>>> .flow_ctrl = dwmac4_flow_ctrl,
>>>> diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>>>> index 3e40578..e30034d 100644
>>>> --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>>>> +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c
>>>> @@ -1271,6 +1271,24 @@ static void free_dma_desc_resources(struct stmmac_priv *priv)
>>>> }
>>>>
>>>> /**
>>>> + * stmmac_mac_enable_rx_queues - Enable MAC rx queues
>>>> + * @priv: driver private structure
>>>> + * Description: It is used for enabling the rx queues in the MAC
>>>> + */
>>>> +static void stmmac_mac_enable_rx_queues(struct stmmac_priv *priv)
>>>> +{
>>>> + int rx_count = priv->dma_cap.number_rx_channel;
>>> priv->dma_cap.number_rx_channel
>>> actually contains the value from register
>>> MAC_HW_Feature2, field RXCHCNT,
>>> which is the number of DMA rx channels.
>>>
>>> This is not the same as the number of MTL
>>> receive queues, field RXQCNT in MAC_HW_Feature2.
>>>
>>> I guess they will often have the same value,
>>> but since there actually are two different fields
>>> for them, I suppose that is not always the case.
>> Yes, you typically have a match between channels and queues.
>> But I can use RXQCNT of course, I agree.
>>
>>>
>>>
>>> Reading the comments in dwmac4_dma.*
>>>
>>> #define DMA_CHANNEL_NB_MAX 1
>>>
>>> "Only Channel 0 is actually configured and used"
>>>
>>> "Following code only done for channel 0, other channels not yet supported"
>>>
>>> Is there any point in actually enabling more than RX queue 0 if the
>>> driver does not yet support more than one channel.
>>> Can RXCHCNT ever be different from RXQCNT?
>>> If so, when? Maybe when using an external DMA IP?
>> Yes, currently stmmac only supports 1 Channel. Bt it needs this feature if the
>> hardware is multi-channel. The hardware I have is multi-channel and so you have
>> to enable RX queue for it to work and that's why I made this fix.
>> In the future I will develope multi channel support for stmmac and this RX queue
>> enable will be already made.
>
> I understand that for multi-queue hardware, RX queue 0 is default off,
> but perhaps it is safer to only enable RX queue 0,
> even if you have more than one RX queue.
> (Only until you have implemented actual support for multi-queues
> in the driver.)
>
> But if you know that it's safe to enable all RX queues even if the
> driver only uses RX queue 0, then perhaps it doesn't matter.

I think it won't bring problems to enable all the available queues even if the
driver only uses queue 0. My QoS reference design has 4 RX queues and it works fine.

>
>
>>
>>>
>>>> + int queue = 0;
>>>> +
>>>> + /* If GMAC does not have multiqueues, then this is not necessary*/
>>>> + if (rx_count == 1)
>>>> + return;
>>>> +
>>>> + for (queue = 0; queue < rx_count; queue++)
>>>> + priv->hw->mac->rx_queue_enable(priv->hw, queue);
>>>> +}
>>>> +
>>>> +/**
>>>> * stmmac_dma_operation_mode - HW DMA operation mode
>>>> * @priv: driver private structure
>>>> * Description: it is used for configuring the DMA operation mode register in
>>>> @@ -1691,6 +1709,9 @@ static int stmmac_hw_setup(struct net_device *dev, bool init_ptp)
>>>> /* Initialize the MAC Core */
>>>> priv->hw->mac->core_init(priv->hw, dev->mtu);
>>>>
>>>> + /* Initialize MAC RX Queues */
>>>> + stmmac_mac_enable_rx_queues(priv);
>>>> +
>>>> ret = priv->hw->mac->rx_ipc(priv->hw);
>>>> if (!ret) {
>>>> netdev_warn(priv->dev, "RX IPC Checksum Offload disabled\n");
>