Re: [PATCH net-next v2 3/8] net: phy: meson-gxl: add read and write helpers for bank registers
On Thu, Dec 07, 2017 at 05:02:35PM +0100, Andrew Lunn wrote: > > Banks actually comes from the datasheet, Yes. > > I don't mind renaming it but I would be making things up. As you wish ? > > Keep it as is for the moment. > > > Does the usual pages comes with this weird toggle thing to open the access ? > > Would we able to use these generic helpers with our this kind of quirks ? > > I don't think the API has been defined yet. But what has been > discussed is adding functions to struct phy_driver. The driver can > then implement whatever is needed to select a given page. There will > then be helpers which take the lock, select the page, do the > read/write, select page 0, and unlock. I'm not sure adding generic helpers really works, because the indirection through phy_driver just makes the code more complex. For Marvell, I ended up with: http://git.armlinux.org.uk/cgit/linux-arm.git/commit/?h=phy&id=9ca46084228bb1b8851e7d24276d85c4ec6e13ae and the preceding three commits. The "generic" versions I came up with were basically lifting marvell_read_paged(), marvell_write_paged() and marvell_modify_paged() to phylib, along with the lower leve marvell_save_page(), marvell_select_page() and marvell_restore_page(). The result is a fair amount of out-of-line code and an assumption that it's a single register. As soon as a PHY has other requirements, these generic implementations don't work. Also, unfortunately, we can't get help from sparse for statically checking the locking - the __acquire()/__release() annotations don't work for mutexes. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line in suburbia: sync at 8.8Mbps down 630kbps up According to speedtest.net: 8.21Mbps down 510kbps up
Re: [PATCH net-next v2 3/8] net: phy: meson-gxl: add read and write helpers for bank registers
On Thu, Dec 07, 2017 at 03:27:10PM +0100, Jerome Brunet wrote: > Add read and write helpers to manipulate banked registers on this PHY > This helps clarify the settings applied to these registers in the init > function and upcoming changes. > > Signed-off-by: Jerome Brunet > --- > drivers/net/phy/meson-gxl.c | 103 > > 1 file changed, 67 insertions(+), 36 deletions(-) > > diff --git a/drivers/net/phy/meson-gxl.c b/drivers/net/phy/meson-gxl.c > index d82aa8cea401..05054770aefb 100644 > --- a/drivers/net/phy/meson-gxl.c > +++ b/drivers/net/phy/meson-gxl.c > @@ -45,11 +45,13 @@ > #define FR_PLL_DIV0 0x1c > #define FR_PLL_DIV1 0x1d > > -static int meson_gxl_config_init(struct phy_device *phydev) > +static int meson_gxl_open_banks(struct phy_device *phydev) Hi Jerome Does the word bank come from the datasheet? Most of the phy drives use page instead. Also, we have discovered a race condition which affects drivers using pages, which can lead to corruption of registers. At some point, i expect we will be adding helpers to access paged registers, which do the right thing with respect to locks. So it would be nice if you used the work page, not bank. Thanks Andrew
Re: [PATCH net-next v2 3/8] net: phy: meson-gxl: add read and write helpers for bank registers
On 07/12/2017 16:46, Andrew Lunn wrote: > On Thu, Dec 07, 2017 at 03:27:10PM +0100, Jerome Brunet wrote: >> Add read and write helpers to manipulate banked registers on this PHY >> This helps clarify the settings applied to these registers in the init >> function and upcoming changes. >> >> Signed-off-by: Jerome Brunet >> --- >> drivers/net/phy/meson-gxl.c | 103 >> >> 1 file changed, 67 insertions(+), 36 deletions(-) >> >> diff --git a/drivers/net/phy/meson-gxl.c b/drivers/net/phy/meson-gxl.c >> index d82aa8cea401..05054770aefb 100644 >> --- a/drivers/net/phy/meson-gxl.c >> +++ b/drivers/net/phy/meson-gxl.c >> @@ -45,11 +45,13 @@ >> #define FR_PLL_DIV0 0x1c >> #define FR_PLL_DIV1 0x1d >> >> -static int meson_gxl_config_init(struct phy_device *phydev) >> +static int meson_gxl_open_banks(struct phy_device *phydev) > > Hi Jerome > > Does the word bank come from the datasheet? Most of the phy drives use > page instead. Yes, it's explicitly described as banks in the datasheet. Neil > > Also, we have discovered a race condition which affects drivers using > pages, which can lead to corruption of registers. At some point, i > expect we will be adding helpers to access paged registers, which do > the right thing with respect to locks. > > So it would be nice if you used the work page, not bank. > >Thanks > > Andrew > > ___ > linux-arm-kernel mailing list > linux-arm-ker...@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel >
Re: [PATCH net-next v2 3/8] net: phy: meson-gxl: add read and write helpers for bank registers
On Thu, 2017-12-07 at 16:46 +0100, Andrew Lunn wrote: > On Thu, Dec 07, 2017 at 03:27:10PM +0100, Jerome Brunet wrote: > > Add read and write helpers to manipulate banked registers on this PHY > > This helps clarify the settings applied to these registers in the init > > function and upcoming changes. > > > > Signed-off-by: Jerome Brunet > > --- > > drivers/net/phy/meson-gxl.c | 103 - > > --- > > 1 file changed, 67 insertions(+), 36 deletions(-) > > > > diff --git a/drivers/net/phy/meson-gxl.c b/drivers/net/phy/meson-gxl.c > > index d82aa8cea401..05054770aefb 100644 > > --- a/drivers/net/phy/meson-gxl.c > > +++ b/drivers/net/phy/meson-gxl.c > > @@ -45,11 +45,13 @@ > > #define FR_PLL_DIV00x1c > > #define FR_PLL_DIV10x1d > > > > -static int meson_gxl_config_init(struct phy_device *phydev) > > +static int meson_gxl_open_banks(struct phy_device *phydev) > > Hi Jerome > > Does the word bank come from the datasheet? Most of the phy drives use > page instead. > > Also, we have discovered a race condition which affects drivers using > pages, which can lead to corruption of registers. At some point, i > expect we will be adding helpers to access paged registers, which do > the right thing with respect to locks. > > So it would be nice if you used the work page, not bank. Banks actually comes from the datasheet, Yes. I don't mind renaming it but I would be making things up. As you wish ? Does the usual pages comes with this weird toggle thing to open the access ? Would we able to use these generic helpers with our this kind of quirks ? > >Thanks > > Andrew
Re: [PATCH net-next v2 3/8] net: phy: meson-gxl: add read and write helpers for bank registers
> Banks actually comes from the datasheet, Yes. > I don't mind renaming it but I would be making things up. As you wish ? Keep it as is for the moment. > Does the usual pages comes with this weird toggle thing to open the access ? > Would we able to use these generic helpers with our this kind of quirks ? I don't think the API has been defined yet. But what has been discussed is adding functions to struct phy_driver. The driver can then implement whatever is needed to select a given page. There will then be helpers which take the lock, select the page, do the read/write, select page 0, and unlock. Supporting this funny toggle should not be a problem. Andrew
