[PATCH v1 1/2] modpost: file2alias: fixup mdio alias garbled code in modules.alias

After module compilation, module alias mechanism will generate a ugly
mdio modules alias configure if ethernet phy was selected, this patch
is to fixup mdio alias garbled code.

In addition, that ugly alias configure will cause ethernet phy module
doens't match udev, phy module auto-load is fail, but add this patch
that it is well mdio driver alias configure match phy device uevent.

Signed-off-by: Yinbo Zhu <zhuyinbo@loongson.cn>
---
 scripts/mod/file2alias.c | 17 +----------------
 1 file changed, 1 insertion(+), 16 deletions(-)

diff --git a/scripts/mod/file2alias.c b/scripts/mod/file2alias.c
index 49aba86..5ba1039 100644
--- a/scripts/mod/file2alias.c
+++ b/scripts/mod/file2alias.c

@@ -1027,24 +1027,9 @@ static int do_platform_entry(const char *filename,
 static int do_mdio_entry(const char *filename,
 			 void *symval, char *alias)
 {
-	int i;
 	DEF_FIELD(symval, mdio_device_id, phy_id);
-	DEF_FIELD(symval, mdio_device_id, phy_id_mask);
-
 	alias += sprintf(alias, MDIO_MODULE_PREFIX);
-
-	for (i = 0; i < 32; i++) {
-		if (!((phy_id_mask >> (31-i)) & 1))
-			*(alias++) = '?';
-		else if ((phy_id >> (31-i)) & 1)
-			*(alias++) = '1';
-		else
-			*(alias++) = '0';
-	}
-
-	/* Terminate the string */
-	*alias = 0;
-
+	ADD(alias, "p", phy_id != 0, phy_id);
 	return 1;
 }
 

-- 
1.8.3.1

the phy_id is only phy identifier, that phy module auto-load function
should according the phy_id event rather than other information, this
patch is remove other unnecessary information and add phy_id event in
mdio_uevent function and ethernet phy module auto-load function will
work well.

Signed-off-by: Yinbo Zhu <zhuyinbo@loongson.cn>
---
 drivers/net/phy/mdio_bus.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/net/phy/mdio_bus.c b/drivers/net/phy/mdio_bus.c
index 6865d93..999f0d4 100644
--- a/drivers/net/phy/mdio_bus.c
+++ b/drivers/net/phy/mdio_bus.c

@@ -962,12 +962,12 @@ static int mdio_bus_match(struct device *dev, struct device_driver *drv)
 
 static int mdio_uevent(struct device *dev, struct kobj_uevent_env *env)
 {
-	int rc;
+	struct phy_device *pdev;
 
-	/* Some devices have extra OF data and an OF-style MODALIAS */
-	rc = of_device_uevent_modalias(dev, env);
-	if (rc != -ENODEV)
-		return rc;
+	pdev = to_phy_device(dev);
+
+	if (add_uevent_var(env, "MODALIAS=mdio:p%08X", pdev->phy_id))
+		return -ENOMEM;
 
 	return 0;
 }

@@ -991,7 +991,7 @@ static int mdio_uevent(struct device *dev, struct kobj_uevent_env *env)
 };
 
 struct bus_type mdio_bus_type = {
-	.name		= "mdio_bus",
+	.name		= "mdio",
 	.dev_groups	= mdio_bus_dev_groups,
 	.match		= mdio_bus_match,
 	.uevent		= mdio_uevent,

-- 
1.8.3.1

On Mon, Nov 22, 2021 at 08:14:57PM +0800, Yinbo Zhu wrote:

After module compilation, module alias mechanism will generate a ugly
mdio modules alias configure if ethernet phy was selected, this patch
is to fixup mdio alias garbled code.

In addition, that ugly alias configure will cause ethernet phy module
doens't match udev, phy module auto-load is fail, but add this patch
that it is well mdio driver alias configure match phy device uevent.

What PHY do you have problems with? What is the PHY id and which
driver should be loaded.

This code has existed a long time, so suddenly saying it is wrong and
changing it needs a good explanation why it is wrong. Being ugly is
not a good reason.

    Andrew

On Mon, Nov 22, 2021 at 08:14:58PM +0800, Yinbo Zhu wrote:

The MDIO bus contains more than just PHYs. This completely breaks
anything that isn't a PHY device - likely by performing an
out-of-bounds access.

This change also _totally_ breaks any MDIO devices that rely on
matching via the "of:" mechanism using the compatible specified in
DT. An example of that is the B53 DSA switch.

Sorry, but we've already learnt this lesson from a similar case with
SPI. Once one particular way of dealing with MODALIAS has been
established for auto-loading modules for a subsystem, it is very
difficult to change it without causing regressions.

We need a very clear description of the problem that these patches are
attempting to address, and then we need to see that effort has been
put in to verify that changing the auto-loading mechanism is safe to
do - such as auditing every single driver that use the MDIO subsystem.

This looks like an unrelated user-interface breaking change. This
changes the path of all MDIO devices and drivers in /sys/bus/mdio_bus/*

Thanks.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!

在 2021/11/22 下午10:07, Andrew Lunn 写道:

On Mon, Nov 22, 2021 at 08:14:57PM +0800, Yinbo Zhu wrote:

quoted

After module compilation, module alias mechanism will generate a ugly
mdio modules alias configure if ethernet phy was selected, this patch
is to fixup mdio alias garbled code.

In addition, that ugly alias configure will cause ethernet phy module
doens't match udev, phy module auto-load is fail, but add this patch
that it is well mdio driver alias configure match phy device uevent.

What PHY do you have problems with? What is the PHY id and which
driver should be loaded.

     about that phy id,  phy dev read it from  PHY Identifier 1 and 
Identifier 2 register, phy driver will call MODULE_DEVICE_TABLE to 
configure

     phy id to mdio_device_id, phy id was used to do a match phy driver 
with phy device.  that phy problems is phy driver was select 'M' then it

     doesn't be auto load.

This code has existed a long time, so suddenly saying it is wrong and
changing it needs a good explanation why it is wrong. Being ugly is
not a good reason.

     Andrew

Hi Andrew,

     Use default mdio configure, After module compilation, mdio alias 
configure is "alias mdio:0000000101000001000011111001???? marvell"

     and it doesn't match  the match phy dev(mdio dev)  uevent, because 
the mdio alias configure "0000000101000001000011111001????"

    include "?" and  "binary number",   as general, uevent it include 
one string or some string that string consist of one character and one 
hexadecimal digit ,

     which uevent is reported by mdio when mdio register a device for 
ethernet phy device, only uevent from phy dev match alias configure from

     phy driver that phy driver will can be auto-load when phy driver 
was selected  'M'.


BRs

Yinbo Zhu.