lkml.org 
[lkml]   [2017]   [Nov]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v4 7/8] netdev: octeon-ethernet: Add Cavium Octeon III support.
From
Date
On 11/29/2017 08:07 AM, Souptick Joarder wrote:
> On Wed, Nov 29, 2017 at 4:00 PM, Souptick Joarder <jrdr.linux@gmail.com> wrote:
>> On Wed, Nov 29, 2017 at 6:25 AM, David Daney <david.daney@cavium.com> wrote:
>>> From: Carlos Munoz <cmunoz@cavium.com>
>>>
>>> The Cavium OCTEON cn78xx and cn73xx SoCs have network packet I/O
>>> hardware that is significantly different from previous generations of
>>> the family.
>
>>> diff --git a/drivers/net/ethernet/cavium/octeon/octeon3-bgx-port.c b/drivers/net/ethernet/cavium/octeon/octeon3-bgx-port.c
>>> new file mode 100644
>>> index 000000000000..4dad35fa4270
>>> --- /dev/null
>>> +++ b/drivers/net/ethernet/cavium/octeon/octeon3-bgx-port.c
>>> @@ -0,0 +1,2033 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +/* Copyright (c) 2017 Cavium, Inc.
>>> + *
>>> + * This file is subject to the terms and conditions of the GNU General Public
>>> + * License. See the file "COPYING" in the main directory of this archive
>>> + * for more details.
>>> + */
>>> +#include <linux/platform_device.h>
>>> +#include <linux/netdevice.h>
>>> +#include <linux/etherdevice.h>
>>> +#include <linux/of_platform.h>
>>> +#include <linux/of_address.h>
>>> +#include <linux/of_mdio.h>
>>> +#include <linux/of_net.h>
>>> +#include <linux/module.h>
>>> +#include <linux/slab.h>
>>> +#include <linux/list.h>
>>> +
>
>>> +static void bgx_port_sgmii_set_link_down(struct bgx_port_priv *priv)
>>> +{
>>> + u64 data;
>
>>> + data = oct_csr_read(BGX_GMP_PCS_MISC_CTL(priv->node, priv->bgx, priv->index));
>>> + data |= BIT(11);
>>> + oct_csr_write(data, BGX_GMP_PCS_MISC_CTL(priv->node, priv->bgx, priv->index));
>>> + data = oct_csr_read(BGX_GMP_PCS_MISC_CTL(priv->node, priv->bgx, priv->index));
>>
>> Any particular reason to read immediately after write ?
>

Yes, to ensure the write is committed to hardware before the next step.

>
>
>>> +static int bgx_port_sgmii_set_link_speed(struct bgx_port_priv *priv, struct port_status status)
>>> +{
>>> + u64 data;
>>> + u64 prtx;
>>> + u64 miscx;
>>> + int timeout;
>>> +
>
>>> +
>>> + switch (status.speed) {
>>> + case 10:
>>
>> In my opinion, instead of hard coding the value, is it fine to use ENUM ?
> Similar comments applicable in other places where hard coded values are used.
>

There is nothing to be gained by interposing an extra layer of
abstraction in this case. The code is more clear with the raw numbers
in this particular case.


>
>
>>> +static int bgx_port_gser_27882(struct bgx_port_priv *priv)
>>> +{
>>> + u64 data;
>>> + u64 addr;
>>
>>> + int timeout = 200;
>>> +
>>> + // timeout = 200;
> Better to initialize the timeout value

What are you talking about? It is properly initialized using valid C code.


>
>
>>> +static int bgx_port_qlm_rx_equalization(struct bgx_port_priv *priv, int qlm, int lane)
>>> +{
>>> + lmode = oct_csr_read(GSER_LANE_MODE(priv->node, qlm));
>>> + lmode &= 0xf;
>>> + addr = GSER_LANE_P_MODE_1(priv->node, qlm, lmode);
>>> + data = oct_csr_read(addr);
>>> + /* Don't complete rx equalization if in VMA manual mode */
>>> + if (data & BIT(14))
>>> + return 0;
>>> +
>>> + /* Apply rx equalization for speed > 6250 */
>>> + if (bgx_port_get_qlm_speed(priv, qlm) < 6250)
>>> + return 0;
>>> +
>>> + /* Wait until rx data is valid (CDRLOCK) */
>>> + timeout = 500;
>>
>> 500 us is the min required value or it can be further reduced ?
>


500 uS works well and is shorter than the 2000 uS from the hardware manual.

If you would like to verify shorter timeout values, we could consider
merging such a patch. But really, this doesn't matter as it is a very
short one-off action when the link is brought up.

>
>>> +static int bgx_port_init_xaui_link(struct bgx_port_priv *priv)
>>> +{
>
>>> +
>>> + if (use_ber) {
>>> + timeout = 10000;
>>> + do {
>>> + data =
>>> + oct_csr_read(BGX_SPU_BR_STATUS1(priv->node, priv->bgx, priv->index));
>>> + if (data & BIT(0))
>>> + break;
>>> + timeout--;
>>> + udelay(1);
>>> + } while (timeout);
>>
>> In my opinion, it's better to implement similar kind of loops inside macros.

Ok, duly noted. I think we are in disagreement with respect to this point.

>>
>>> + if (!timeout) {
>>> + pr_debug("BGX%d:%d:%d: BLK_LOCK timeout\n",
>>> + priv->bgx, priv->index, priv->node);
>>> + return -1;
>>> + }
>>> + } else {
>>> + timeout = 10000;
>>> + do {
>>> + data =
>>> + oct_csr_read(BGX_SPU_BX_STATUS(priv->node, priv->bgx, priv->index));
>>> + if (data & BIT(12))
>>> + break;
>>> + timeout--;
>>> + udelay(1);
>>> + } while (timeout);
>> same here

\
 
 \ /
  Last update: 2017-11-29 20:21    [W:0.127 / U:0.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site