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[2/4] net: sfp: allow to use also SFP modules which are detected as SFF

Message ID 20201230154755.14746-3-pali@kernel.org (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series net: sfp: add support for GPON RTL8672/RTL9601C and Ubiquiti U-Fiber | expand

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Commit Message

Pali Rohár Dec. 30, 2020, 3:47 p.m. UTC
Some GPON SFP modules (e.g. Ubiquiti U-Fiber Instant) have set SFF phys_id
in their EEPROM. Kernel SFP subsystem currently does not allow to use
modules detected as SFF.

This change extends check for SFP modules so also those with SFF phys_id
are allowed. With this change also GPON SFP module Ubiquiti U-Fiber Instant
is recognized.

Signed-off-by: Pali Rohár <pali@kernel.org>
---
 drivers/net/phy/sfp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

Comments

Russell King (Oracle) Dec. 30, 2020, 4:11 p.m. UTC | #1
On Wed, Dec 30, 2020 at 04:47:53PM +0100, Pali Rohár wrote:
> Some GPON SFP modules (e.g. Ubiquiti U-Fiber Instant) have set SFF phys_id
> in their EEPROM. Kernel SFP subsystem currently does not allow to use
> modules detected as SFF.
> 
> This change extends check for SFP modules so also those with SFF phys_id
> are allowed. With this change also GPON SFP module Ubiquiti U-Fiber Instant
> is recognized.

I really don't want to do this for every single module out there.
It's likely that Ubiquiti do this crap as a vendor lock-in measure.
Let's make it specific to Ubiquiti modules _only_ until such time
that we know better.
Pali Rohár Dec. 30, 2020, 5:06 p.m. UTC | #2
On Wednesday 30 December 2020 16:11:51 Russell King - ARM Linux admin wrote:
> On Wed, Dec 30, 2020 at 04:47:53PM +0100, Pali Rohár wrote:
> > Some GPON SFP modules (e.g. Ubiquiti U-Fiber Instant) have set SFF phys_id
> > in their EEPROM. Kernel SFP subsystem currently does not allow to use
> > modules detected as SFF.
> > 
> > This change extends check for SFP modules so also those with SFF phys_id
> > are allowed. With this change also GPON SFP module Ubiquiti U-Fiber Instant
> > is recognized.
> 
> I really don't want to do this for every single module out there.
> It's likely that Ubiquiti do this crap as a vendor lock-in measure.
> Let's make it specific to Ubiquiti modules _only_ until such time
> that we know better.

Ok. This module_supported() function is called in sfp_sm_mod_probe()
function. Current code is:

	/* Check whether we support this module */
	if (!sfp->type->module_supported(&id)) {
		dev_err(sfp->dev,
			"module is not supported - phys id 0x%02x 0x%02x\n",
			sfp->id.base.phys_id, sfp->id.base.phys_ext_id);
		return -EINVAL;
	}

Do you want to change code to something like this?

	/* Check whether we support this module */
	if (!sfp->type->module_supported(&id) &&
	    (memcmp(id.base.vendor_name, "UBNT            ", 16) ||
	     memcmp(id.base.vendor_pn, "UF-INSTANT      ", 16)))
		dev_err(sfp->dev,
			"module is not supported - phys id 0x%02x 0x%02x\n",
			sfp->id.base.phys_id, sfp->id.base.phys_ext_id);
		return -EINVAL;
	}

Or do you have a better idea how to skip that module_supported check for
this UBNT SFP?
Marek Behún Dec. 30, 2020, 5:27 p.m. UTC | #3
On Wed, 30 Dec 2020 18:06:52 +0100
Pali Rohár <pali@kernel.org> wrote:

> 	if (!sfp->type->module_supported(&id) &&
> 	    (memcmp(id.base.vendor_name, "UBNT            ", 16) ||
> 	     memcmp(id.base.vendor_pn, "UF-INSTANT      ", 16)))

I would rather add a quirk member (bitfield) to the sfp structure and do
something like this

if (!sfp->type->module_supported(&id) &&
    !(sfp->quirks & SFP_QUIRK_BAD_PHYS_ID))

or maybe put this check into the module_supported method.

Marek
Russell King (Oracle) Dec. 30, 2020, 7:12 p.m. UTC | #4
On Wed, Dec 30, 2020 at 06:27:07PM +0100, Marek Behún wrote:
> On Wed, 30 Dec 2020 18:06:52 +0100
> Pali Rohár <pali@kernel.org> wrote:
> 
> > 	if (!sfp->type->module_supported(&id) &&
> > 	    (memcmp(id.base.vendor_name, "UBNT            ", 16) ||
> > 	     memcmp(id.base.vendor_pn, "UF-INSTANT      ", 16)))
> 
> I would rather add a quirk member (bitfield) to the sfp structure and do
> something like this
> 
> if (!sfp->type->module_supported(&id) &&
>     !(sfp->quirks & SFP_QUIRK_BAD_PHYS_ID))
> 
> or maybe put this check into the module_supported method.

Sorry, definitely not. If you've ever looked at the SDHCI driver with
its multiple "quirks" bitfields, doing this is a recipe for creating
a very horrid hard to understand mess.

What you suggest just results in yet more complexity.
Pali Rohár Dec. 31, 2020, 1:52 p.m. UTC | #5
On Wednesday 30 December 2020 19:12:40 Russell King - ARM Linux admin wrote:
> On Wed, Dec 30, 2020 at 06:27:07PM +0100, Marek Behún wrote:
> > On Wed, 30 Dec 2020 18:06:52 +0100
> > Pali Rohár <pali@kernel.org> wrote:
> > 
> > > 	if (!sfp->type->module_supported(&id) &&
> > > 	    (memcmp(id.base.vendor_name, "UBNT            ", 16) ||
> > > 	     memcmp(id.base.vendor_pn, "UF-INSTANT      ", 16)))
> > 
> > I would rather add a quirk member (bitfield) to the sfp structure and do
> > something like this
> > 
> > if (!sfp->type->module_supported(&id) &&
> >     !(sfp->quirks & SFP_QUIRK_BAD_PHYS_ID))
> > 
> > or maybe put this check into the module_supported method.
> 
> Sorry, definitely not. If you've ever looked at the SDHCI driver with
> its multiple "quirks" bitfields, doing this is a recipe for creating
> a very horrid hard to understand mess.
> 
> What you suggest just results in yet more complexity.

Should I rather put this vendor name/pn check into the
sfp_module_supported() function?

static bool sfp_module_supported(const struct sfp_eeprom_id *id)
{
	if (id->base.phys_id == SFF8024_ID_SFP &&
	    id->base.phys_ext_id == SFP_PHYS_EXT_ID_SFP)
		return true;

	if (id->base.phys_id == SFF8024_ID_SFF_8472 &&
	    id->base.phys_ext_id == SFP_PHYS_EXT_ID_SFP &&
	    !memcmp(id->base.vendor_name, "UBNT            ", 16) &&
	    !memcmp(id->base.vendor_pn, "UF-INSTANT      ", 16))
		return true;

	return false;
}
diff mbox series

Patch

diff --git a/drivers/net/phy/sfp.c b/drivers/net/phy/sfp.c
index 490e78a72dd6..73f3ecf15260 100644
--- a/drivers/net/phy/sfp.c
+++ b/drivers/net/phy/sfp.c
@@ -273,7 +273,8 @@  static const struct sff_data sff_data = {
 
 static bool sfp_module_supported(const struct sfp_eeprom_id *id)
 {
-	return id->base.phys_id == SFF8024_ID_SFP &&
+	return (id->base.phys_id == SFF8024_ID_SFP ||
+		id->base.phys_id == SFF8024_ID_SFF_8472) &&
 	       id->base.phys_ext_id == SFP_PHYS_EXT_ID_SFP;
 }