From: gregory.clement@free-electrons•com (Gregory CLEMENT)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v5 net-next 4/7] net: mvneta: Convert to be 64 bits compatible
Date: Thu, 01 Dec 2016 13:01:20 +0100 [thread overview]
Message-ID: <874m2nluy7.fsf@free-electrons.com> (raw)
In-Reply-To: <CAPv3WKeJBL7_V_7QPVNDAd9H4bgeLcSF8enuD96sgEmecuRkRA@mail.gmail.com> (Marcin Wojtas's message of "Thu, 1 Dec 2016 12:48:39 +0100")
Hi Jisheng,
On jeu., d?c. 01 2016, Marcin Wojtas <mw@semihalf•com> wrote:
> Hi Jisheng,
>
> Which baseline do you use?
>
> It took me really lot of time to catch why RX broke after rebase from
> LKv4.1 to LKv4.4. Between those two, in commit:
> 97303480753e ("arm64: Increase the max granular size")
> L1_CACHE_BYTES for all ARMv8 platforms was increased to 128B and so
> did NET_SKB_PAD.
>
> And 128 is more than the maximum that can fit into packet offset
> [11:8]@0x1400. In such case this correction is needed. Did it answer
> your doubts?
I can confirm also that without this patch it just doesn't work.
Gregory
>
> Best regards,
> Marcin
>
>
>
> 2016-12-01 12:26 GMT+01:00 Jisheng Zhang <jszhang@marvell•com>:
>> Hi Gregory, Marcin,
>>
>> On Wed, 30 Nov 2016 22:42:49 +0100 Gregory CLEMENT wrote:
>>
>>> From: Marcin Wojtas <mw@semihalf•com>
>>>
>>> Prepare the mvneta driver in order to be usable on the 64 bits platform
>>> such as the Armada 3700.
>>>
>>> [gregory.clement at free-electrons.com]: this patch was extract from a larger
>>> one to ease review and maintenance.
>>>
>>> Signed-off-by: Marcin Wojtas <mw@semihalf•com>
>>> Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons•com>
>>> ---
>>> drivers/net/ethernet/marvell/mvneta.c | 17 ++++++++++++++++-
>>> 1 file changed, 16 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/net/ethernet/marvell/mvneta.c b/drivers/net/ethernet/marvell/mvneta.c
>>> index 92b9af14c352..8ef03fb69bcd 100644
>>> --- a/drivers/net/ethernet/marvell/mvneta.c
>>> +++ b/drivers/net/ethernet/marvell/mvneta.c
>>> @@ -296,6 +296,12 @@
>>> /* descriptor aligned size */
>>> #define MVNETA_DESC_ALIGNED_SIZE 32
>>>
>>> +/* Number of bytes to be taken into account by HW when putting incoming data
>>> + * to the buffers. It is needed in case NET_SKB_PAD exceeds maximum packet
>>> + * offset supported in MVNETA_RXQ_CONFIG_REG(q) registers.
>>
>> We also brought up this driver on 64bit platforms, we doesn't have this
>> patch. Maybe I'm wrong, I'm trying to understand why we need this
>> modification. Let's assume the NET_SKB_PAD is 64B, we call
>> mvneta_rxq_offset_set(pp, rxq, 64),
>>
>> {
>> u32 val;
>>
>> val = mvreg_read(pp, MVNETA_RXQ_CONFIG_REG(rxq->id));
>> val &= ~MVNETA_RXQ_PKT_OFFSET_ALL_MASK;
>>
>> /* Offset is in */
>> val |= MVNETA_RXQ_PKT_OFFSET_MASK(offset >> 3);
>> // then this will be "val |= 8;" it doesn't exceeds the max offset of
>> MVNETA_RXQ_CONFIG_REG(q) register.
>>
>> Could you please kindly point out where I am wrong?
>>
>>> + */
>>> +#define MVNETA_RX_PKT_OFFSET_CORRECTION 64
>>> +
>>> #define MVNETA_RX_PKT_SIZE(mtu) \
>>> ALIGN((mtu) + MVNETA_MH_SIZE + MVNETA_VLAN_TAG_LEN + \
>>> ETH_HLEN + ETH_FCS_LEN, \
>>> @@ -416,6 +422,7 @@ struct mvneta_port {
>>> u64 ethtool_stats[ARRAY_SIZE(mvneta_statistics)];
>>>
>>> u32 indir[MVNETA_RSS_LU_TABLE_SIZE];
>>> + u16 rx_offset_correction;
>>> };
>>>
>>> /* The mvneta_tx_desc and mvneta_rx_desc structures describe the
>>> @@ -1807,6 +1814,7 @@ static int mvneta_rx_refill(struct mvneta_port *pp,
>>> return -ENOMEM;
>>> }
>>>
>>> + phys_addr += pp->rx_offset_correction;
>>> mvneta_rx_desc_fill(rx_desc, phys_addr, data, rxq);
>>> return 0;
>>> }
>>> @@ -2782,7 +2790,7 @@ static int mvneta_rxq_init(struct mvneta_port *pp,
>>> mvreg_write(pp, MVNETA_RXQ_SIZE_REG(rxq->id), rxq->size);
>>>
>>> /* Set Offset */
>>> - mvneta_rxq_offset_set(pp, rxq, NET_SKB_PAD);
>>> + mvneta_rxq_offset_set(pp, rxq, NET_SKB_PAD - pp->rx_offset_correction);
>>>
>>> /* Set coalescing pkts and time */
>>> mvneta_rx_pkts_coal_set(pp, rxq, rxq->pkts_coal);
>>> @@ -4033,6 +4041,13 @@ static int mvneta_probe(struct platform_device *pdev)
>>>
>>> pp->rxq_def = rxq_def;
>>>
>>> + /* Set RX packet offset correction for platforms, whose
>>> + * NET_SKB_PAD, exceeds 64B. It should be 64B for 64-bit
>>> + * platforms and 0B for 32-bit ones.
>>
>> Even we need this patch, I'm not sure this last comment is correct or not.
>> NET_SKB_PAD is defined as:
>>
>> #define NET_SKB_PAD max(32, L1_CACHE_BYTES)
>>
>> we have 64B cacheline 32bit platforms, on this platforms, the NET_SKB_PAD
>> should be 64B as well.
>>
>> Thanks,
>> Jisheng
--
Gregory Clement, Free Electrons
Kernel, drivers, real-time and embedded Linux
development, consulting, training and support.
http://free-electrons.com
next prev parent reply other threads:[~2016-12-01 12:01 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-30 21:42 [PATCH v5 net-next 0/7] Support Armada 37xx SoC (ARMv8 64-bits) in mvneta driver Gregory CLEMENT
2016-11-30 21:42 ` [PATCH v5 net-next 1/7] net: mvneta: Optimize rx path for small frame Gregory CLEMENT
2016-11-30 21:42 ` [PATCH v5 net-next 2/7] net: mvneta: Do not allocate buffer in rxq init with HWBM Gregory CLEMENT
2016-11-30 21:42 ` [PATCH v5 net-next 3/7] net: mvneta: Use cacheable memory to store the rx buffer virtual address Gregory CLEMENT
2016-12-01 11:38 ` Jisheng Zhang
2016-11-30 21:42 ` [PATCH v5 net-next 4/7] net: mvneta: Convert to be 64 bits compatible Gregory CLEMENT
2016-12-01 11:26 ` Jisheng Zhang
2016-12-01 11:41 ` Jisheng Zhang
2016-12-01 11:48 ` Marcin Wojtas
2016-12-01 12:01 ` Gregory CLEMENT [this message]
2016-12-01 12:02 ` Jisheng Zhang
2016-12-01 12:16 ` Jisheng Zhang
2016-12-01 12:33 ` Marcin Wojtas
2016-11-30 21:42 ` [PATCH v5 net-next 5/7] net: mvneta: Only disable mvneta_bm for 64-bits Gregory CLEMENT
2016-11-30 21:42 ` [PATCH v5 net-next 6/7] net: mvneta: Add network support for Armada 3700 SoC Gregory CLEMENT
2016-11-30 21:42 ` [PATCH v5 net-next 7/7] ARM64: dts: marvell: Add network support for Armada 3700 Gregory CLEMENT
2016-12-01 16:05 ` Marcin Wojtas
2016-12-01 16:07 ` [PATCH v5 net-next 0/7] Support Armada 37xx SoC (ARMv8 64-bits) in mvneta driver Marcin Wojtas
2016-12-01 16:09 ` Gregory CLEMENT
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