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Date: Wed, 29 Nov 2017 11:20:55 -0800
From: David Daney <ddaney@...iumnetworks.com>
To: Souptick Joarder <jrdr.linux@...il.com>,
David Daney <david.daney@...ium.com>
Cc: linux-mips@...ux-mips.org, ralf@...ux-mips.org,
James Hogan <james.hogan@...s.com>, netdev@...r.kernel.org,
"David S. Miller" <davem@...emloft.net>,
Rob Herring <robh+dt@...nel.org>,
Mark Rutland <mark.rutland@....com>,
devel@...verdev.osuosl.org,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
linux-kernel@...r.kernel.org,
"Steven J. Hill" <steven.hill@...ium.com>,
devicetree@...r.kernel.org, Andrew Lunn <andrew@...n.ch>,
Florian Fainelli <f.fainelli@...il.com>,
Carlos Munoz <cmunoz@...ium.com>
Subject: Re: [PATCH v4 7/8] netdev: octeon-ethernet: Add Cavium Octeon III
support.
On 11/29/2017 08:07 AM, Souptick Joarder wrote:
> On Wed, Nov 29, 2017 at 4:00 PM, Souptick Joarder <jrdr.linux@...il.com> wrote:
>> On Wed, Nov 29, 2017 at 6:25 AM, David Daney <david.daney@...ium.com> wrote:
>>> From: Carlos Munoz <cmunoz@...ium.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
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