Implement the suspend/resume procedure for the Broadcom AC131 and BCM5241 type
of PHYs (10/100 only) by entering the standard power down followed by the
proprietary standby mode in the auxiliary mode 4 shadow register. On resume,
the PHY software reset is enough to make it come out of standby mode so we can
utilize brcm_fet_config_init() as the resume hook.
Signed-off-by: Florian Fainelli <[email protected]>
---
drivers/net/phy/broadcom.c | 48 ++++++++++++++++++++++++++++++++++++++
include/linux/brcmphy.h | 1 +
2 files changed, 49 insertions(+)
diff --git a/drivers/net/phy/broadcom.c b/drivers/net/phy/broadcom.c
index 31fbcdddc9ad..739348b3f135 100644
--- a/drivers/net/phy/broadcom.c
+++ b/drivers/net/phy/broadcom.c
@@ -766,6 +766,50 @@ static irqreturn_t brcm_fet_handle_interrupt(struct phy_device *phydev)
return IRQ_HANDLED;
}
+static int brcm_fet_suspend(struct phy_device *phydev)
+{
+ int reg, err, err2, brcmtest;
+
+ /* We cannot use a read/modify/write here otherwise the PHY continues
+ * to drive LEDs which defeats the purpose of low power mode.
+ */
+ err = phy_write(phydev, MII_BMCR, BMCR_PDOWN);
+ 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;
+
+ /* Set standby mode */
+ reg = phy_read(phydev, MII_BRCM_FET_SHDW_AUXMODE4);
+ if (reg < 0) {
+ err = reg;
+ goto done;
+ }
+
+ reg |= MII_BRCM_FET_SHDW_AM4_STANDBY;
+
+ err = phy_write(phydev, MII_BRCM_FET_SHDW_AUXMODE4, reg);
+ if (err < 0)
+ goto done;
+
+done:
+ /* 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;
@@ -1033,6 +1077,8 @@ static struct phy_driver broadcom_drivers[] = {
.config_init = brcm_fet_config_init,
.config_intr = brcm_fet_config_intr,
.handle_interrupt = brcm_fet_handle_interrupt,
+ .suspend = brcm_fet_suspend,
+ .resume = brcm_fet_config_init,
}, {
.phy_id = PHY_ID_BCM5241,
.phy_id_mask = 0xfffffff0,
@@ -1041,6 +1087,8 @@ static struct phy_driver broadcom_drivers[] = {
.config_init = brcm_fet_config_init,
.config_intr = brcm_fet_config_intr,
.handle_interrupt = brcm_fet_handle_interrupt,
+ .suspend = brcm_fet_suspend,
+ .resume = brcm_fet_config_init,
}, {
.phy_id = PHY_ID_BCM5395,
.phy_id_mask = 0xfffffff0,
diff --git a/include/linux/brcmphy.h b/include/linux/brcmphy.h
index 6ff567ece34a..9e77165f3ef6 100644
--- a/include/linux/brcmphy.h
+++ b/include/linux/brcmphy.h
@@ -293,6 +293,7 @@
#define MII_BRCM_FET_SHDW_MC_FAME 0x4000 /* Force Auto MDIX enable */
#define MII_BRCM_FET_SHDW_AUXMODE4 0x1a /* Auxiliary mode 4 */
+#define MII_BRCM_FET_SHDW_AM4_STANDBY 0x0008 /* Standby enable */
#define MII_BRCM_FET_SHDW_AM4_LED_MASK 0x0003
#define MII_BRCM_FET_SHDW_AM4_LED_MODE1 0x0001
--
2.25.1
On 8/15/22 11:00, Russell King (Oracle) wrote:
> On Mon, Aug 15, 2022 at 10:43:56AM -0700, Florian Fainelli wrote:
>> + /* We cannot use a read/modify/write here otherwise the PHY continues
>> + * to drive LEDs which defeats the purpose of low power mode.
>> + */
> ...
>> + /* Set standby mode */
>> + reg = phy_read(phydev, MII_BRCM_FET_SHDW_AUXMODE4);
>> + if (reg < 0) {
>> + err = reg;
>> + goto done;
>> + }
>> +
>> + reg |= MII_BRCM_FET_SHDW_AM4_STANDBY;
>> +
>> + err = phy_write(phydev, MII_BRCM_FET_SHDW_AUXMODE4, reg);
>
> Does the read-modify-write problem extend to this register? Why would
> the PHY behave differently whether you used phy_modify() here or not?
> On the mdio bus, it should be exactly the same - the only difference
> is that we're guaranteed to hold the lock over the sequence whereas
> this drops and re-acquires the lock.
What read-modify-write problem are you referring to, that is, are you
talking about my statement about setting BMCR.PDOWN only or something else?
I could use phy_modify(), sure.
--
Florian
On Mon, Aug 15, 2022 at 10:43:56AM -0700, Florian Fainelli wrote:
> + /* We cannot use a read/modify/write here otherwise the PHY continues
> + * to drive LEDs which defeats the purpose of low power mode.
> + */
...
> + /* Set standby mode */
> + reg = phy_read(phydev, MII_BRCM_FET_SHDW_AUXMODE4);
> + if (reg < 0) {
> + err = reg;
> + goto done;
> + }
> +
> + reg |= MII_BRCM_FET_SHDW_AM4_STANDBY;
> +
> + err = phy_write(phydev, MII_BRCM_FET_SHDW_AUXMODE4, reg);
Does the read-modify-write problem extend to this register? Why would
the PHY behave differently whether you used phy_modify() here or not?
On the mdio bus, it should be exactly the same - the only difference
is that we're guaranteed to hold the lock over the sequence whereas
this drops and re-acquires the lock.
If it's sensitive to the timing of the read and the write, it suggests
the above code is fragile - maybe there needs to be a minimum delay
inserted between the read and the write?
--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!
On 8/15/22 11:09, Florian Fainelli wrote:
> On 8/15/22 11:00, Russell King (Oracle) wrote:
>> On Mon, Aug 15, 2022 at 10:43:56AM -0700, Florian Fainelli wrote:
>>> + /* We cannot use a read/modify/write here otherwise the PHY
>>> continues
>>> + * to drive LEDs which defeats the purpose of low power mode.
>>> + */
>> ...
>>> + /* Set standby mode */
>>> + reg = phy_read(phydev, MII_BRCM_FET_SHDW_AUXMODE4);
>>> + if (reg < 0) {
>>> + err = reg;
>>> + goto done;
>>> + }
>>> +
>>> + reg |= MII_BRCM_FET_SHDW_AM4_STANDBY;
>>> +
>>> + err = phy_write(phydev, MII_BRCM_FET_SHDW_AUXMODE4, reg);
>>
>> Does the read-modify-write problem extend to this register? Why would
>> the PHY behave differently whether you used phy_modify() here or not?
>> On the mdio bus, it should be exactly the same - the only difference
>> is that we're guaranteed to hold the lock over the sequence whereas
>> this drops and re-acquires the lock.
>
> What read-modify-write problem are you referring to, that is, are you
> talking about my statement about setting BMCR.PDOWN only or something else?
Sorry, hit send too quickly, I see what problem you are referring to. v2
coming up shortly utilizing phy_modify() and simplifying the return path
(no need for done label, etc.)
Thanks
--
Florian