>-----Original Message-----
>From: Andrew Lunn <andrew@xxxxxxx>
>Sent: Wednesday, July 24, 2019 6:18 PM
>To: Claudiu Manoil <claudiu.manoil@xxxxxxx>
>Cc: David S . Miller <davem@xxxxxxxxxxxxx>; Rob Herring
><robh+dt@xxxxxxxxxx>; Leo Li <leoyang.li@xxxxxxx>; Alexandru Marginean
><alexandru.marginean@xxxxxxx>; netdev@xxxxxxxxxxxxxxx;
>devicetree@xxxxxxxxxxxxxxx; linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-
>kernel@xxxxxxxxxxxxxxx
>Subject: Re: [PATCH net-next v1 1/4] enetc: Clean up local mdio bus allocation
>
>On Wed, Jul 24, 2019 at 05:41:38PM +0300, Claudiu Manoil wrote:
>> Though it works, this is not how it should have been.
>> What's needed is a pointer to the mdio registers.
>> Store it properly inside bus->priv allocated space.
>> Use devm_* variant to further clean up the init error /
>> remove paths.
>>
>> Fixes following sparse warning:
>> warning: incorrect type in assignment (different address spaces)
>> expected void *priv
>> got struct enetc_mdio_regs [noderef] <asn:2>*[assigned] regs
>>
>> Fixes: ebfcb23d62ab ("enetc: Add ENETC PF level external MDIO support")
>>
>> Signed-off-by: Claudiu Manoil <claudiu.manoil@xxxxxxx>
>> ---
>> v1 - added this patch
>>
>> .../net/ethernet/freescale/enetc/enetc_mdio.c | 31 +++++++------------
>> 1 file changed, 12 insertions(+), 19 deletions(-)
>>
>> diff --git a/drivers/net/ethernet/freescale/enetc/enetc_mdio.c
>b/drivers/net/ethernet/freescale/enetc/enetc_mdio.c
>> index 77b9cd10ba2b..1e3cd21c13ee 100644
>> --- a/drivers/net/ethernet/freescale/enetc/enetc_mdio.c
>> +++ b/drivers/net/ethernet/freescale/enetc/enetc_mdio.c
>> @@ -15,7 +15,8 @@ struct enetc_mdio_regs {
>> u32 mdio_addr; /* MDIO address */
>> };
>>
>> -#define bus_to_enetc_regs(bus) (struct enetc_mdio_regs __iomem
>*)((bus)->priv)
>> +#define bus_to_enetc_regs(bus) (*(struct enetc_mdio_regs __iomem
>**) \
>> + ((bus)->priv))
>>
>> #define ENETC_MDIO_REG_OFFSET 0x1c00
>> #define ENETC_MDC_DIV 258
>> @@ -146,12 +147,12 @@ static int enetc_mdio_read(struct mii_bus *bus, int
>phy_id, int regnum)
>> int enetc_mdio_probe(struct enetc_pf *pf)
>> {
>> struct device *dev = &pf->si->pdev->dev;
>> - struct enetc_mdio_regs __iomem *regs;
>> + struct enetc_mdio_regs __iomem **regsp;
>> struct device_node *np;
>> struct mii_bus *bus;
>> - int ret;
>> + int err;
>>
>> - bus = mdiobus_alloc_size(sizeof(regs));
>> + bus = devm_mdiobus_alloc_size(dev, sizeof(*regsp));
>> if (!bus)
>> return -ENOMEM;
>>
>> @@ -159,41 +160,33 @@ int enetc_mdio_probe(struct enetc_pf *pf)
>> bus->read = enetc_mdio_read;
>> bus->write = enetc_mdio_write;
>> bus->parent = dev;
>> + regsp = bus->priv;
>> snprintf(bus->id, MII_BUS_ID_SIZE, "%s", dev_name(dev));
>>
>> /* store the enetc mdio base address for this bus */
>> - regs = pf->si->hw.port + ENETC_MDIO_REG_OFFSET;
>> - bus->priv = regs;
>> + *regsp = pf->si->hw.port + ENETC_MDIO_REG_OFFSET;
>
>This is all very odd and different to every other driver.
>
>If i get the code write, there are 4 registers, each u32 in size,
>starting at pf->si->hw.port + ENETC_MDIO_REG_OFFSET?
>
>There are macros like enetc_port_wr() and enetc_global_wr(). It think
>it would be much cleaner to add a macro enet_mdio_wr() which takes
>hw, off, val.
>
>#define enet_mdio_wr(hw, off, val) enet_port_wr(hw, off +
>ENETC_MDIO_REG_OFFSET, val)
>
>struct enetc_mdio_priv {
> struct enetc_hw *hw;
>}
>
> struct enetc_mdio_priv *mdio_priv;
>
> bus = devm_mdiobus_alloc_size(dev, sizeof(*mdio_priv));
>
> mdio_priv = bus->priv;
> mdio_priv->hw = pf->si->hw;
>
>
>static int enetc_mdio_write(struct mii_bus *bus, int phy_id, int regnum,
> u16 value)
>{
> struct enetc_mdio_priv *mdio_priv = bus->priv;
>...
> enet_mdio_wr(priv->hw, ENETC_MDIO_CFG, mdio_cfg);
>}
>
>All the horrible casts go away, the driver is structured like every
>other driver, sparse is probably happy, etc.
>
This looks more like a matter cosmetic preferences. I mean, I didn't
notice anything "horrible" in the code so far. I actually find it more
ugly to define a new structure with only one element inside, like:
struct enetc_mdio_priv {
struct enetc_hw *hw;
}
What is this technique called? Looks like a second type definition for
another type.
Anyway, if others already did this in the kernel, what can I do?
