[PATCH] net: phy: broadcom: add support for BCM5221 phy

[PATCH] net: phy: broadcom: add support for BCM5221 phy

[Giulio Benetti]

This patch adds the BCM5221 PHY support by reusing
brcm_fet_config_intr() and brcm_fet_handle_interrupt() and
implementing config_init()/suspend()/resume().

Sponsored by: Tekvox Inc.
Cc: Jim Reinhart <jimr@tekvox.com>
Cc: James Autry <jautry@tekvox.com>
Cc: Matthew Maron <matthewm@tekvox.com>
Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
---
 drivers/net/phy/broadcom.c | 144 +++++++++++++++++++++++++++++++++++++
 include/linux/brcmphy.h    |   8 +++
 2 files changed, 152 insertions(+)

diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
index 59cae0d808aa..99f6c0485f01 100644
--- a/drivers/net/phy/broadcom.c
+++ b/drivers/net/phy/broadcom.c
@@ -754,6 +754,84 @@ static int brcm_fet_config_init(struct phy_device *phydev)
 	return err;
 }
 
+static int bcm5221_config_init(struct phy_device *phydev)
+{
+	int reg, err, err2, brcmtest;
+
+	/* Reset the PHY to bring it to a known state. */
+	err = phy_write(phydev, MII_BMCR, BMCR_RESET);
+	if (err < 0)
+		return err;
+
+	/* The datasheet indicates the PHY needs up to 1us to complete a reset,
+	 * build some slack here.
+	 */
+	usleep_range(1000, 2000);
+
+	/* The PHY requires 65 MDC clock cycles to complete a write operation
+	 * and turnaround the line properly.
+	 *
+	 * We ignore -EIO here as the MDIO controller (e.g.: mdio-bcm-unimac)
+	 * may flag the lack of turn-around as a read failure. This is
+	 * particularly true with this combination since the MDIO controller
+	 * only used 64 MDC cycles. This is not a critical failure in this
+	 * specific case and it has no functional impact otherwise, so we let
+	 * that one go through. If there is a genuine bus error, the next read
+	 * of MII_BRCM_FET_INTREG will error out.
+	 */
+	err = phy_read(phydev, MII_BMCR);
+	if (err < 0 && err != -EIO)
+		return err;
+
+	reg = phy_read(phydev, MII_BRCM_FET_INTREG);
+	if (reg < 0)
+		return reg;
+
+	/* Unmask events we are interested in and mask interrupts globally. */
+	reg = MII_BRCM_FET_IR_ENABLE |
+	      MII_BRCM_FET_IR_MASK;
+
+	err = phy_write(phydev, MII_BRCM_FET_INTREG, reg);
+	if (err < 0)
+		return err;
+
+	/* Enable auto MDIX */
+	err = phy_clear_bits(phydev, BCM5221_AEGSR, BCM5221_AEGSR_MDIX_DIS);
+	if (err < 0)
+		return err;
+
+	/* Enable shadow register access */
+	brcmtest = phy_read(phydev, MII_BRCM_FET_BRCMTEST);
+	if (brcmtest < 0)
+		return brcmtest;
+
+	reg = brcmtest | MII_BRCM_FET_BT_SRE;
+
+	err = phy_write(phydev, MII_BRCM_FET_BRCMTEST, reg);
+	if (err < 0)
+		return err;
+
+        /* Exit low power mode */
+	err = phy_clear_bits(phydev, MII_BRCM_FET_SHDW_AUXMODE4,
+			 BCM5221_SHDW_AM4_FORCE_LPM);
+	if (err < 0)
+		goto done;
+
+	if (phydev->dev_flags & PHY_BRCM_AUTO_PWRDWN_ENABLE) {
+		/* Enable auto power down */
+		err = phy_set_bits(phydev, MII_BRCM_FET_SHDW_AUXSTAT2,
+				   MII_BRCM_FET_SHDW_AS2_APDE);
+	}
+
+done:
+	/* Disable shadow register access */
+	err2 = phy_write(phydev, MII_BRCM_FET_BRCMTEST, brcmtest);
+	if (!err)
+		err = err2;
+
+	return err;
+}
+
 static int brcm_fet_ack_interrupt(struct phy_device *phydev)
 {
 	int reg;
@@ -882,6 +960,61 @@ static int bcm54xx_phy_set_wol(struct phy_device *phydev,
 	return 0;
 }
 
+static int bcm5221_suspend(struct phy_device *phydev)
+{
+	int reg, err, err2, brcmtest;
+
+	/* Enable shadow register access */
+	brcmtest = phy_read(phydev, MII_BRCM_FET_BRCMTEST);
+	if (brcmtest < 0)
+		return brcmtest;
+
+	reg = brcmtest | MII_BRCM_FET_BT_SRE;
+
+	err = phy_write(phydev, MII_BRCM_FET_BRCMTEST, reg);
+	if (err < 0)
+		return err;
+
+	/* Force Low Power Mode with clock enabled */
+	err = phy_set_bits(phydev, MII_BRCM_FET_SHDW_AUXMODE4,
+			   BCM5221_SHDW_AM4_EN_CLK_LPM |
+			   BCM5221_SHDW_AM4_FORCE_LPM);
+
+	/* Disable shadow register access */
+	err2 = phy_write(phydev, MII_BRCM_FET_BRCMTEST, brcmtest);
+	if (!err)
+		err = err2;
+
+	return err;
+}
+
+static int bcm5221_resume(struct phy_device *phydev)
+{
+	int reg, err, err2, brcmtest;
+
+	/* Enable shadow register access */
+	brcmtest = phy_read(phydev, MII_BRCM_FET_BRCMTEST);
+	if (brcmtest < 0)
+		return brcmtest;
+
+	reg = brcmtest | MII_BRCM_FET_BT_SRE;
+
+	err = phy_write(phydev, MII_BRCM_FET_BRCMTEST, reg);
+	if (err < 0)
+		return err;
+
+	/* Exit Low Power Mode with clock enabled */
+	err = phy_clear_bits(phydev, MII_BRCM_FET_SHDW_AUXMODE4,
+			     BCM5221_SHDW_AM4_FORCE_LPM);
+
+	/* Disable shadow register access */
+	err2 = phy_write(phydev, MII_BRCM_FET_BRCMTEST, brcmtest);
+	if (!err)
+		err = err2;
+
+	return err;
+}
+
 static int bcm54xx_phy_probe(struct phy_device *phydev)
 {
 	struct bcm54xx_phy_priv *priv;
@@ -1208,6 +1341,16 @@ static struct phy_driver broadcom_drivers[] = {
 	.handle_interrupt = brcm_fet_handle_interrupt,
 	.suspend	= brcm_fet_suspend,
 	.resume		= brcm_fet_config_init,
+}, {
+	.phy_id		= PHY_ID_BCM5221,
+	.phy_id_mask	= 0xfffffff0,
+	.name		= "Broadcom BCM5221",
+	/* PHY_BASIC_FEATURES */
+	.config_init	= bcm5221_config_init,
+	.config_intr	= brcm_fet_config_intr,
+	.handle_interrupt = brcm_fet_handle_interrupt,
+	.suspend	= bcm5221_suspend,
+	.resume		= bcm5221_resume,
 }, {
 	.phy_id		= PHY_ID_BCM5395,
 	.phy_id_mask	= 0xfffffff0,
@@ -1288,6 +1431,7 @@ static struct mdio_device_id __maybe_unused broadcom_tbl[] = {
 	{ PHY_ID_BCM53125, 0xfffffff0 },
 	{ PHY_ID_BCM53128, 0xfffffff0 },
 	{ PHY_ID_BCM89610, 0xfffffff0 },
+	{ PHY_ID_BCM5221, 0xfffffff0 },
 	{ }
 };
 
diff --git a/include/linux/brcmphy.h b/include/linux/brcmphy.h
index 5d732f48f787..3d7786cc997d 100644
--- a/include/linux/brcmphy.h
+++ b/include/linux/brcmphy.h
@@ -12,6 +12,7 @@
 #define PHY_ID_BCM50610			0x0143bd60
 #define PHY_ID_BCM50610M		0x0143bd70
 #define PHY_ID_BCM5241			0x0143bc30
+#define PHY_ID_BCM5221			0x004061e0
 #define PHY_ID_BCMAC131			0x0143bc70
 #define PHY_ID_BCM5481			0x0143bca0
 #define PHY_ID_BCM5395			0x0143bcf0
@@ -330,6 +331,13 @@
 
 #define BCM54XX_WOL_INT_STATUS		(MII_BCM54XX_EXP_SEL_WOL + 0x94)
 
+/* BCM5221 Registers */
+#define BCM5221_AEGSR			0x1C
+#define BCM5221_AEGSR_MDIX_DIS		BIT(11)
+
+#define BCM5221_SHDW_AM4_EN_CLK_LPM	BIT(2)
+#define BCM5221_SHDW_AM4_FORCE_LPM	BIT(1)
+
 /*****************************************************************************/
 /* Fast Ethernet Transceiver definitions. */
 /*****************************************************************************/
-- 
2.34.1

Re: [PATCH] net: phy: broadcom: add support for BCM5221 phy

[Andrew Lunn]

On Fri, Aug 11, 2023 at 11:53:22PM +0200, Giulio Benetti wrote:
> This patch adds the BCM5221 PHY support by reusing
> brcm_fet_config_intr() and brcm_fet_handle_interrupt() and
> implementing config_init()/suspend()/resume().
> 
> Sponsored by: Tekvox Inc.

That is a new tag. Maybe you should update
Documentation/process/submitting-patches.rst ?

> +static int bcm5221_config_init(struct phy_device *phydev)
> +{
> +	int reg, err, err2, brcmtest;
> +
> +	/* Reset the PHY to bring it to a known state. */
> +	err = phy_write(phydev, MII_BMCR, BMCR_RESET);
> +	if (err < 0)
> +		return err;
> +
> +	/* The datasheet indicates the PHY needs up to 1us to complete a reset,
> +	 * build some slack here.
> +	 */
> +	usleep_range(1000, 2000);
> +
> +	/* The PHY requires 65 MDC clock cycles to complete a write operation
> +	 * and turnaround the line properly.
> +	 *
> +	 * We ignore -EIO here as the MDIO controller (e.g.: mdio-bcm-unimac)
> +	 * may flag the lack of turn-around as a read failure. This is
> +	 * particularly true with this combination since the MDIO controller
> +	 * only used 64 MDC cycles. This is not a critical failure in this
> +	 * specific case and it has no functional impact otherwise, so we let
> +	 * that one go through. If there is a genuine bus error, the next read
> +	 * of MII_BRCM_FET_INTREG will error out.
> +	 */
> +	err = phy_read(phydev, MII_BMCR);
> +	if (err < 0 && err != -EIO)
> +		return err;

It is pretty normal to check the value of MII_BMCR and ensure that
BMCR_RESET has cleared. See phy_poll_reset(). It might not be needed,
if you trust the datasheet, but 802.3 C22 says it should clear.

> +	/* Enable auto MDIX */
> +	err = phy_clear_bits(phydev, BCM5221_AEGSR, BCM5221_AEGSR_MDIX_DIS);
> +	if (err < 0)
> +		return err;

It is better to set it based on phydev->mdix_ctrl.

> @@ -1288,6 +1431,7 @@ static struct mdio_device_id __maybe_unused broadcom_tbl[] = {
>  	{ PHY_ID_BCM53125, 0xfffffff0 },
>  	{ PHY_ID_BCM53128, 0xfffffff0 },
>  	{ PHY_ID_BCM89610, 0xfffffff0 },
> +	{ PHY_ID_BCM5221, 0xfffffff0 },

This table has some sort of sorting. I would put this new entry before
PHY_ID_BCM5241.

>  #define PHY_ID_BCM50610			0x0143bd60
>  #define PHY_ID_BCM50610M		0x0143bd70
>  #define PHY_ID_BCM5241			0x0143bc30
> +#define PHY_ID_BCM5221			0x004061e0

The value looks odd. Is the OUI correct? Is that a broadcom OUI?

    Andrew

---
pw-bot: cr

Re: [PATCH] net: phy: broadcom: add support for BCM5221 phy

[Florian Fainelli]

[-- Attachment #1: Type: text/plain, Size: 2573 bytes --]

On 8/11/23 15:16, Andrew Lunn wrote:
> On Fri, Aug 11, 2023 at 11:53:22PM +0200, Giulio Benetti wrote:
>> This patch adds the BCM5221 PHY support by reusing
>> brcm_fet_config_intr() and brcm_fet_handle_interrupt() and
>> implementing config_init()/suspend()/resume().
>>
>> Sponsored by: Tekvox Inc.
> 
> That is a new tag. Maybe you should update
> Documentation/process/submitting-patches.rst ?
> 
>> +static int bcm5221_config_init(struct phy_device *phydev)
>> +{
>> +	int reg, err, err2, brcmtest;
>> +
>> +	/* Reset the PHY to bring it to a known state. */
>> +	err = phy_write(phydev, MII_BMCR, BMCR_RESET);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	/* The datasheet indicates the PHY needs up to 1us to complete a reset,
>> +	 * build some slack here.
>> +	 */
>> +	usleep_range(1000, 2000);
>> +
>> +	/* The PHY requires 65 MDC clock cycles to complete a write operation
>> +	 * and turnaround the line properly.
>> +	 *
>> +	 * We ignore -EIO here as the MDIO controller (e.g.: mdio-bcm-unimac)
>> +	 * may flag the lack of turn-around as a read failure. This is
>> +	 * particularly true with this combination since the MDIO controller
>> +	 * only used 64 MDC cycles. This is not a critical failure in this
>> +	 * specific case and it has no functional impact otherwise, so we let
>> +	 * that one go through. If there is a genuine bus error, the next read
>> +	 * of MII_BRCM_FET_INTREG will error out.
>> +	 */
>> +	err = phy_read(phydev, MII_BMCR);
>> +	if (err < 0 && err != -EIO)
>> +		return err;
> 
> It is pretty normal to check the value of MII_BMCR and ensure that
> BMCR_RESET has cleared. See phy_poll_reset(). It might not be needed,
> if you trust the datasheet, but 802.3 C22 says it should clear.
> 
>> +	/* Enable auto MDIX */
>> +	err = phy_clear_bits(phydev, BCM5221_AEGSR, BCM5221_AEGSR_MDIX_DIS);
>> +	if (err < 0)
>> +		return err;
> 
> It is better to set it based on phydev->mdix_ctrl.
> 
>> @@ -1288,6 +1431,7 @@ static struct mdio_device_id __maybe_unused broadcom_tbl[] = {
>>   	{ PHY_ID_BCM53125, 0xfffffff0 },
>>   	{ PHY_ID_BCM53128, 0xfffffff0 },
>>   	{ PHY_ID_BCM89610, 0xfffffff0 },
>> +	{ PHY_ID_BCM5221, 0xfffffff0 },
> 
> This table has some sort of sorting. I would put this new entry before
> PHY_ID_BCM5241.
> 
>>   #define PHY_ID_BCM50610			0x0143bd60
>>   #define PHY_ID_BCM50610M		0x0143bd70
>>   #define PHY_ID_BCM5241			0x0143bc30
>> +#define PHY_ID_BCM5221			0x004061e0
> 
> The value looks odd. Is the OUI correct? Is that a broadcom OUI?

Yes it is correct and yes it is assigned to Broadcom.
-- 
Florian


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Re: [PATCH] net: phy: broadcom: add support for BCM5221 phy

[Andrew Lunn]

> > This table has some sort of sorting. I would put this new entry before
> > PHY_ID_BCM5241.
> > 
> > >   #define PHY_ID_BCM50610			0x0143bd60
> > >   #define PHY_ID_BCM50610M		0x0143bd70
> > >   #define PHY_ID_BCM5241			0x0143bc30
> > > +#define PHY_ID_BCM5221			0x004061e0
> > 
> > The value looks odd. Is the OUI correct? Is that a broadcom OUI?
> 
> Yes it is correct and yes it is assigned to Broadcom.

I found a datasheet for this PHY and it does list this OUI. I just
noticed it is the only device supported by this driver which uses this
OUI, so i just wanted to check.

     Andrew

Re: [PATCH] net: phy: broadcom: add support for BCM5221 phy

[Giulio Benetti]

Hello Andrew,

thank you for reviewing,

On 12/08/23 00:16, Andrew Lunn wrote:
> On Fri, Aug 11, 2023 at 11:53:22PM +0200, Giulio Benetti wrote:
>> This patch adds the BCM5221 PHY support by reusing
>> brcm_fet_config_intr() and brcm_fet_handle_interrupt() and
>> implementing config_init()/suspend()/resume().
>>
>> Sponsored by: Tekvox Inc.
> 
> That is a new tag. Maybe you should update
> Documentation/process/submitting-patches.rst ?

I've picked this tag from commit:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=73c289bac05919286f8c7e1660fcaf6ec0468363

it's not "Sponsored-by:", do you think it's better using this last form?

I can send a patch along with V2 of this one for that.

>> +static int bcm5221_config_init(struct phy_device *phydev)
>> +{
>> +	int reg, err, err2, brcmtest;
>> +
>> +	/* Reset the PHY to bring it to a known state. */
>> +	err = phy_write(phydev, MII_BMCR, BMCR_RESET);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	/* The datasheet indicates the PHY needs up to 1us to complete a reset,
>> +	 * build some slack here.
>> +	 */
>> +	usleep_range(1000, 2000);
>> +
>> +	/* The PHY requires 65 MDC clock cycles to complete a write operation
>> +	 * and turnaround the line properly.
>> +	 *
>> +	 * We ignore -EIO here as the MDIO controller (e.g.: mdio-bcm-unimac)
>> +	 * may flag the lack of turn-around as a read failure. This is
>> +	 * particularly true with this combination since the MDIO controller
>> +	 * only used 64 MDC cycles. This is not a critical failure in this
>> +	 * specific case and it has no functional impact otherwise, so we let
>> +	 * that one go through. If there is a genuine bus error, the next read
>> +	 * of MII_BRCM_FET_INTREG will error out.
>> +	 */
>> +	err = phy_read(phydev, MII_BMCR);
>> +	if (err < 0 && err != -EIO)
>> +		return err;
> 
> It is pretty normal to check the value of MII_BMCR and ensure that
> BMCR_RESET has cleared. See phy_poll_reset(). It might not be needed,
> if you trust the datasheet, but 802.3 C22 says it should clear.

oh ok, I'll do that on V2

> 
>> +	/* Enable auto MDIX */
>> +	err = phy_clear_bits(phydev, BCM5221_AEGSR, BCM5221_AEGSR_MDIX_DIS);
>> +	if (err < 0)
>> +		return err;
> 
> It is better to set it based on phydev->mdix_ctrl.

ok,

> 
>> @@ -1288,6 +1431,7 @@ static struct mdio_device_id __maybe_unused broadcom_tbl[] = {
>>   	{ PHY_ID_BCM53125, 0xfffffff0 },
>>   	{ PHY_ID_BCM53128, 0xfffffff0 },
>>   	{ PHY_ID_BCM89610, 0xfffffff0 },
>> +	{ PHY_ID_BCM5221, 0xfffffff0 },
> 
> This table has some sort of sorting. I would put this new entry before
> PHY_ID_BCM5241.

right, this and even the struct phy_driver driver entry too then,

> 
>>   #define PHY_ID_BCM50610			0x0143bd60
>>   #define PHY_ID_BCM50610M		0x0143bd70
>>   #define PHY_ID_BCM5241			0x0143bc30
>> +#define PHY_ID_BCM5221			0x004061e0
> 
> The value looks odd. Is the OUI correct? Is that a broadcom OUI?

Yes, you can check it in the pdf page 37:
https://docs.broadcom.com/doc/5221-DS07-405-RDS.pdf
and yes, it's odd.

Thanks again for the review, I'll do the changes here and the others
suggested by the other and send V2 patch.

Best regards
-- 
Giulio Benetti
CEO&CTO@Benetti Engineering sas

Re: [PATCH] net: phy: broadcom: add support for BCM5221 phy

[Russell King (Oracle)]

On Fri, Aug 11, 2023 at 11:53:22PM +0200, Giulio Benetti wrote:
> +	reg = phy_read(phydev, MII_BRCM_FET_INTREG);
> +	if (reg < 0)
> +		return reg;
> +
> +	/* Unmask events we are interested in and mask interrupts globally. */
> +	reg = MII_BRCM_FET_IR_ENABLE |
> +	      MII_BRCM_FET_IR_MASK;
> +
> +	err = phy_write(phydev, MII_BRCM_FET_INTREG, reg);
> +	if (err < 0)
> +		return err;

Please explain why you read MII_BRCM_FET_INTREG, then discard its value
and write a replacement value.

> +
> +	/* Enable auto MDIX */
> +	err = phy_clear_bits(phydev, BCM5221_AEGSR, BCM5221_AEGSR_MDIX_DIS);
> +	if (err < 0)
> +		return err;
> +
> +	/* Enable shadow register access */
> +	brcmtest = phy_read(phydev, MII_BRCM_FET_BRCMTEST);
> +	if (brcmtest < 0)
> +		return brcmtest;
> +
> +	reg = brcmtest | MII_BRCM_FET_BT_SRE;
> +
> +	err = phy_write(phydev, MII_BRCM_FET_BRCMTEST, reg);
> +	if (err < 0)
> +		return err;

I think you should consider locking the MDIO bus while the device is
switched to the shadow register set, so that other accesses don't happen
that may interfere with this.

> +static int bcm5221_suspend(struct phy_device *phydev)
> +{
> +	int reg, err, err2, brcmtest;
> +
> +	/* Enable shadow register access */
> +	brcmtest = phy_read(phydev, MII_BRCM_FET_BRCMTEST);
> +	if (brcmtest < 0)
> +		return brcmtest;
> +
> +	reg = brcmtest | MII_BRCM_FET_BT_SRE;
> +
> +	err = phy_write(phydev, MII_BRCM_FET_BRCMTEST, reg);
> +	if (err < 0)
> +		return err;
> +
> +	/* Force Low Power Mode with clock enabled */
> +	err = phy_set_bits(phydev, MII_BRCM_FET_SHDW_AUXMODE4,
> +			   BCM5221_SHDW_AM4_EN_CLK_LPM |
> +			   BCM5221_SHDW_AM4_FORCE_LPM);
> +
> +	/* Disable shadow register access */
> +	err2 = phy_write(phydev, MII_BRCM_FET_BRCMTEST, brcmtest);
> +	if (!err)
> +		err = err2;

Same here.

> +
> +	return err;
> +}
> +
> +static int bcm5221_resume(struct phy_device *phydev)
> +{
> +	int reg, err, err2, brcmtest;
> +
> +	/* Enable shadow register access */
> +	brcmtest = phy_read(phydev, MII_BRCM_FET_BRCMTEST);
> +	if (brcmtest < 0)
> +		return brcmtest;
> +
> +	reg = brcmtest | MII_BRCM_FET_BT_SRE;
> +
> +	err = phy_write(phydev, MII_BRCM_FET_BRCMTEST, reg);
> +	if (err < 0)
> +		return err;
> +
> +	/* Exit Low Power Mode with clock enabled */
> +	err = phy_clear_bits(phydev, MII_BRCM_FET_SHDW_AUXMODE4,
> +			     BCM5221_SHDW_AM4_FORCE_LPM);
> +
> +	/* Disable shadow register access */
> +	err2 = phy_write(phydev, MII_BRCM_FET_BRCMTEST, brcmtest);
> +	if (!err)
> +		err = err2;

And, of course, same here.

Thanks.

-- 
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!

Re: [PATCH] net: phy: broadcom: add support for BCM5221 phy

[Giulio Benetti]

Hello Russell,

thanks for reviewing,

On 12/08/23 00:22, Russell King (Oracle) wrote:
> On Fri, Aug 11, 2023 at 11:53:22PM +0200, Giulio Benetti wrote:
>> +	reg = phy_read(phydev, MII_BRCM_FET_INTREG);
>> +	if (reg < 0)
>> +		return reg;
>> +
>> +	/* Unmask events we are interested in and mask interrupts globally. */
>> +	reg = MII_BRCM_FET_IR_ENABLE |
>> +	      MII_BRCM_FET_IR_MASK;
>> +
>> +	err = phy_write(phydev, MII_BRCM_FET_INTREG, reg);
>> +	if (err < 0)
>> +		return err;
> 
> Please explain why you read MII_BRCM_FET_INTREG, then discard its value
> and write a replacement value.

ok, yes, as it is it doesn't look self-explanatory at all

>> +
>> +	/* Enable auto MDIX */
>> +	err = phy_clear_bits(phydev, BCM5221_AEGSR, BCM5221_AEGSR_MDIX_DIS);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	/* Enable shadow register access */
>> +	brcmtest = phy_read(phydev, MII_BRCM_FET_BRCMTEST);
>> +	if (brcmtest < 0)
>> +		return brcmtest;
>> +
>> +	reg = brcmtest | MII_BRCM_FET_BT_SRE;
>> +
>> +	err = phy_write(phydev, MII_BRCM_FET_BRCMTEST, reg);
>> +	if (err < 0)
>> +		return err;
> 
> I think you should consider locking the MDIO bus while the device is
> switched to the shadow register set, so that other accesses don't happen
> that may interfere with this.

oh, I haven't considered this, you're totally right,

>> +static int bcm5221_suspend(struct phy_device *phydev)
>> +{
>> +	int reg, err, err2, brcmtest;
>> +
>> +	/* Enable shadow register access */
>> +	brcmtest = phy_read(phydev, MII_BRCM_FET_BRCMTEST);
>> +	if (brcmtest < 0)
>> +		return brcmtest;
>> +
>> +	reg = brcmtest | MII_BRCM_FET_BT_SRE;
>> +
>> +	err = phy_write(phydev, MII_BRCM_FET_BRCMTEST, reg);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	/* Force Low Power Mode with clock enabled */
>> +	err = phy_set_bits(phydev, MII_BRCM_FET_SHDW_AUXMODE4,
>> +			   BCM5221_SHDW_AM4_EN_CLK_LPM |
>> +			   BCM5221_SHDW_AM4_FORCE_LPM);
>> +
>> +	/* Disable shadow register access */
>> +	err2 = phy_write(phydev, MII_BRCM_FET_BRCMTEST, brcmtest);
>> +	if (!err)
>> +		err = err2;
> 
> Same here.

ok,

>> +
>> +	return err;
>> +}
>> +
>> +static int bcm5221_resume(struct phy_device *phydev)
>> +{
>> +	int reg, err, err2, brcmtest;
>> +
>> +	/* Enable shadow register access */
>> +	brcmtest = phy_read(phydev, MII_BRCM_FET_BRCMTEST);
>> +	if (brcmtest < 0)
>> +		return brcmtest;
>> +
>> +	reg = brcmtest | MII_BRCM_FET_BT_SRE;
>> +
>> +	err = phy_write(phydev, MII_BRCM_FET_BRCMTEST, reg);
>> +	if (err < 0)
>> +		return err;
>> +
>> +	/* Exit Low Power Mode with clock enabled */
>> +	err = phy_clear_bits(phydev, MII_BRCM_FET_SHDW_AUXMODE4,
>> +			     BCM5221_SHDW_AM4_FORCE_LPM);
>> +
>> +	/* Disable shadow register access */
>> +	err2 = phy_write(phydev, MII_BRCM_FET_BRCMTEST, brcmtest);
>> +	if (!err)
>> +		err = err2;
> 
> And, of course, same here.

ok, will do on V2 along with the other point from Andrew and Florian.

Thanks again for the review,
Best regards
-- 
Giulio Benetti
CEO&CTO@Benetti Engineering sas

Re: [PATCH] net: phy: broadcom: add support for BCM5221 phy

[Florian Fainelli]

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On 8/11/2023 2:53 PM, Giulio Benetti wrote:
> This patch adds the BCM5221 PHY support by reusing
> brcm_fet_config_intr() and brcm_fet_handle_interrupt() and
> implementing config_init()/suspend()/resume().
> 
> Sponsored by: Tekvox Inc.
> Cc: Jim Reinhart <jimr@tekvox.com>
> Cc: James Autry <jautry@tekvox.com>
> Cc: Matthew Maron <matthewm@tekvox.com>
> Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>

Looks good, few comments below.

> ---
>   drivers/net/phy/broadcom.c | 144 +++++++++++++++++++++++++++++++++++++
>   include/linux/brcmphy.h    |   8 +++
>   2 files changed, 152 insertions(+)
> 
> diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
> index 59cae0d808aa..99f6c0485f01 100644
> --- a/drivers/net/phy/broadcom.c
> +++ b/drivers/net/phy/broadcom.c
> @@ -754,6 +754,84 @@ static int brcm_fet_config_init(struct phy_device *phydev)
>   	return err;
>   }
>   
> +static int bcm5221_config_init(struct phy_device *phydev)
> +{

Very similar to brcm_fet_config_init() except that you configure fewer 
interrupt sources, do not have the LED mode programming and your MDI-X 
programming is done via a 10BaseT specific register rather than the shadow.

Can you consider adding parameters to brcm_fet_config_init() such that 
you can specify the 5221 specific settings such as the interrupt mask 
for instance?

This should help address the locking that Russell suggested.

[snip]
>   
> +static int bcm5221_suspend(struct phy_device *phydev)
> +{
> +	int reg, err, err2, brcmtest;
> +
> +	/* Enable shadow register access */
> +	brcmtest = phy_read(phydev, MII_BRCM_FET_BRCMTEST);
> +	if (brcmtest < 0)
> +		return brcmtest;
> +
> +	reg = brcmtest | MII_BRCM_FET_BT_SRE;
> +
> +	err = phy_write(phydev, MII_BRCM_FET_BRCMTEST, reg);
> +	if (err < 0)
> +		return err;
> +
> +	/* Force Low Power Mode with clock enabled */
> +	err = phy_set_bits(phydev, MII_BRCM_FET_SHDW_AUXMODE4,
> +			   BCM5221_SHDW_AM4_EN_CLK_LPM |
> +			   BCM5221_SHDW_AM4_FORCE_LPM);
> +
> +	/* Disable shadow register access */
> +	err2 = phy_write(phydev, MII_BRCM_FET_BRCMTEST, brcmtest);
> +	if (!err)
> +		err = err2;
> +
> +	return err;
> +}

bcm5221_suspend() is essentially brcm_fet_suspend() minus the setting of 
the BMCR.PDOWN bit, can you consider factoring brcm_fet_suspend() into a 
helper that can decide whether to set the power down bit or not? Does 
not brcm_fet_suspend() work as-is?

> +
> +static int bcm5221_resume(struct phy_device *phydev)
> +{

This should really be calling bcm5221_config_init() here, if the PHY was 
on a power island that is powered off during system suspend, 
bcm5221_resume() would not be restoring the auto-power down that is set 
during config_init(), probably not desired because that means you will 
burn power when the cable is disconnected...
-- 
Florian

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Re: [PATCH] net: phy: broadcom: add support for BCM5221 phy

[Giulio Benetti]

Hello Florian,

thanks for reviewing,

On 12/08/23 01:52, Florian Fainelli wrote:
> 
> 
> On 8/11/2023 2:53 PM, Giulio Benetti wrote:
>> This patch adds the BCM5221 PHY support by reusing
>> brcm_fet_config_intr() and brcm_fet_handle_interrupt() and
>> implementing config_init()/suspend()/resume().
>>
>> Sponsored by: Tekvox Inc.
>> Cc: Jim Reinhart <jimr@tekvox.com>
>> Cc: James Autry <jautry@tekvox.com>
>> Cc: Matthew Maron <matthewm@tekvox.com>
>> Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com>
> 
> Looks good, few comments below.
> 
>> ---
>>   drivers/net/phy/broadcom.c | 144 +++++++++++++++++++++++++++++++++++++
>>   include/linux/brcmphy.h    |   8 +++
>>   2 files changed, 152 insertions(+)
>>
>> diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
>> index 59cae0d808aa..99f6c0485f01 100644
>> --- a/drivers/net/phy/broadcom.c
>> +++ b/drivers/net/phy/broadcom.c
>> @@ -754,6 +754,84 @@ static int brcm_fet_config_init(struct phy_device 
>> *phydev)
>>       return err;
>>   }
>> +static int bcm5221_config_init(struct phy_device *phydev)
>> +{
> 
> Very similar to brcm_fet_config_init() except that you configure fewer 
> interrupt sources, do not have the LED mode programming and your MDI-X 
> programming is done via a 10BaseT specific register rather than the shadow.
> 
> Can you consider adding parameters to brcm_fet_config_init() such that 
> you can specify the 5221 specific settings such as the interrupt mask 
> for instance?

So if I've understood correctly I should drop bcm5221_config_init() and
use brcm_fet_config_init() by checking the struct phy_driver .phy_id to
be PHY_ID_BCM5221.

> This should help address the locking that Russell suggested.

But I don't understand how this can help to prevent the locking Russell
suggested, can you please elaborate more or point me and example?
As far as I've understood I should take care to lock sections to prevent
from interrupts to occur during shadow mode switching, is it correct?
So maybe you mean that if I do this in brcm_fet_config_init() it will be
fixed for the other phys using brcm_fet_config_init(), correct?

> [snip]
>> +static int bcm5221_suspend(struct phy_device *phydev)
>> +{
>> +    int reg, err, err2, brcmtest;
>> +
>> +    /* Enable shadow register access */
>> +    brcmtest = phy_read(phydev, MII_BRCM_FET_BRCMTEST);
>> +    if (brcmtest < 0)
>> +        return brcmtest;
>> +
>> +    reg = brcmtest | MII_BRCM_FET_BT_SRE;
>> +
>> +    err = phy_write(phydev, MII_BRCM_FET_BRCMTEST, reg);
>> +    if (err < 0)
>> +        return err;
>> +
>> +    /* Force Low Power Mode with clock enabled */
>> +    err = phy_set_bits(phydev, MII_BRCM_FET_SHDW_AUXMODE4,
>> +               BCM5221_SHDW_AM4_EN_CLK_LPM |
>> +               BCM5221_SHDW_AM4_FORCE_LPM);
>> +
>> +    /* Disable shadow register access */
>> +    err2 = phy_write(phydev, MII_BRCM_FET_BRCMTEST, brcmtest);
>> +    if (!err)
>> +        err = err2;
>> +
>> +    return err;
>> +}
> 
> bcm5221_suspend() is essentially brcm_fet_suspend() minus the setting of 
> the BMCR.PDOWN bit, can you consider factoring brcm_fet_suspend() into a 
> helper that can decide whether to set the power down bit or not? Does 
> not brcm_fet_suspend() work as-is?

Sure, I will,

>> +
>> +static int bcm5221_resume(struct phy_device *phydev)
>> +{
> 
> This should really be calling bcm5221_config_init() here, if the PHY was 
> on a power island that is powered off during system suspend, 
> bcm5221_resume() would not be restoring the auto-power down that is set 
> during config_init(), probably not desired because that means you will 
> burn power when the cable is disconnected...

oh yes! You're right, I will then drop bcm5221_resume() in favor of 
bcm5221_config_init(), so brcm_fet_config_init() with phy_id == 
PHY_ID_BCM5221 checks.

Thanks again
Best regards
-- 
Giulio Benetti
CEO&CTO@Benetti Engineering sas