Re: [RFC net-next PATCH v2 2/2] net: dpaa2-mac: Add ACPI support for DPAA2 MAC driver

Russell King - ARM Linux admin
2020-04-18T11:38:44Z

On Sat, Apr 18, 2020 at 04:24:32PM +0530, Calvin Johnson wrote:
> Modify dpaa2_mac_connect() to support ACPI along with DT.
> Modify dpaa2_mac_get_node() to get the dpmac fwnode from either
> DT or ACPI.
> Replace of_get_phy_mode with fwnode_get_phy_mode to get
> phy-mode for a dpmac_node.
> Define and use helper functions fwnode_phy_match() and
> fwnode_phy_find_device() to find phy_dev that is later
> connected to mac->phylink.
>
> Signed-off-by: Calvin Johnson <calvin.johnson@oss.nxp.com>
> ---
>
> Changes in v2:
> - Major change following other network drivers supporting ACPI
> - dropped v1 patches 1, 2, 4, 5 and 6 as they are no longer valid
> - incorporated other v1 review comments
>
> .../net/ethernet/freescale/dpaa2/dpaa2-mac.c | 122 ++++++++++++++----
> 1 file changed, 94 insertions(+), 28 deletions(-)
>
> diff --git a/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c b/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c
> index 3ee236c5fc37..5a03da54a67f 100644
> --- a/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c
> +++ b/drivers/net/ethernet/freescale/dpaa2/dpaa2-mac.c
> @@ -3,6 +3,9 @@
>
> #include "dpaa2-eth.h"
> #include "dpaa2-mac.h"
> +#include <linux/acpi.h>
> +#include <linux/phy.h>
> +#include <linux/phylink.h>

Why do you need linux/phy.h and linux/phylink.h here? Please try
building the driver without; you'll find they are already included
via dpaa2-mac.h.

> +static int fwnode_phy_match(struct device *dev, const void *phy_fwnode)
> +{
> + return dev->fwnode == phy_fwnode;
> +}
> +
> +static struct phy_device *fwnode_phy_find_device(struct fwnode_handle *phy_fwnode)
> +{
> + struct device *d;
> + struct mdio_device *mdiodev;
> +
> + if (!phy_fwnode)
> + return NULL;
> +
> + d = bus_find_device(&mdio_bus_type, NULL, phy_fwnode, fwnode_phy_match);
> + if (d) {
> + mdiodev = to_mdio_device(d);
> + if (mdiodev->flags & MDIO_DEVICE_FLAG_PHY)
> + return to_phy_device(d);
> + put_device(d);
> + }
> +
> + return NULL;
> +}

This is groping around in the mdio bus implementation details; drivers
must not do this layering violation. Please propose an interface in
the mdio code to do what you need.

> +
> int dpaa2_mac_connect(struct dpaa2_mac *mac)
> {
> struct fsl_mc_device *dpmac_dev = mac->mc_dev;
> struct net_device *net_dev = mac->net_dev;
> - struct device_node *dpmac_node;
> + struct fwnode_handle *dpmac_node = NULL;
> + struct fwnode_reference_args args;
> + struct phy_device *phy_dev;
> struct phylink *phylink;
> struct dpmac_attr attr;
> + int status;
> int err;
>
> err = dpmac_open(mac->mc_io, 0, dpmac_dev->obj_desc.id,
> @@ -251,7 +299,7 @@ int dpaa2_mac_connect(struct dpaa2_mac *mac)
>
> mac->if_link_type = attr.link_type;
>
> - dpmac_node = dpaa2_mac_get_node(attr.id);
> + dpmac_node = dpaa2_mac_get_node(&mac->mc_dev->dev, attr.id);
> if (!dpmac_node) {
> netdev_err(net_dev, "No dpmac@%d node found.\n", attr.id);
> err = -ENODEV;
> @@ -269,7 +317,7 @@ int dpaa2_mac_connect(struct dpaa2_mac *mac)
> * error out if the interface mode requests them and there is no PHY
> * to act upon them
> */
> - if (of_phy_is_fixed_link(dpmac_node) &&
> + if (of_phy_is_fixed_link(to_of_node(dpmac_node)) &&
> (mac->if_mode == PHY_INTERFACE_MODE_RGMII_ID ||
> mac->if_mode == PHY_INTERFACE_MODE_RGMII_RXID ||
> mac->if_mode == PHY_INTERFACE_MODE_RGMII_TXID)) {
> @@ -282,7 +330,7 @@ int dpaa2_mac_connect(struct dpaa2_mac *mac)
> mac->phylink_config.type = PHYLINK_NETDEV;
>
> phylink = phylink_create(&mac->phylink_config,
> - of_fwnode_handle(dpmac_node), mac->if_mode,
> + dpmac_node, mac->if_mode,
> &dpaa2_mac_phylink_ops);
> if (IS_ERR(phylink)) {
> err = PTR_ERR(phylink);
> @@ -290,20 +338,38 @@ int dpaa2_mac_connect(struct dpaa2_mac *mac)
> }
> mac->phylink = phylink;
>
> - err = phylink_of_phy_connect(mac->phylink, dpmac_node, 0);
> + if (is_of_node(dpmac_node))
> + err = phylink_of_phy_connect(mac->phylink,
> + to_of_node(dpmac_node), 0);
> + else if (is_acpi_node(dpmac_node)) {
> + status = acpi_node_get_property_reference(dpmac_node,
> + "phy-handle",
> + 0, &args);
> + if (ACPI_FAILURE(status))
> + goto err_phylink_destroy;
> + phy_dev = fwnode_phy_find_device(args.fwnode);
> + if (!phy_dev)
> + goto err_phylink_destroy;
> +
> + err = phylink_connect_phy(mac->phylink, phy_dev);
> + if (err)
> + phy_detach(phy_dev);

phy_detach() reverses the effect of phy_attach_direct(). This is not
the correct cleanup function in this case, because the PHY hasn't been
attached (and phylink_connect_phy() will clean up any effects it has
on error.) You only need to reverse the effect of your
fwnode_phy_find_device(), which phy_detach() is inappropriate for.

In any case, if this method of getting a PHY is accepted by ACPI folk,
it could be moved into a helper in phylink_fwnode_phy_connect() - and
that really needs to happen before a patch adding this functionality is
acceptable.

> + }
> if (err) {
> - netdev_err(net_dev, "phylink_of_phy_connect() = %d\n", err);
> + netdev_err(net_dev, "phylink_fwnode_phy_connect() = %d\n", err);

That's a very misleading change - there is no function named as per your
new name.

> goto err_phylink_destroy;
> }
>
> - of_node_put(dpmac_node);
> + if (is_of_node(dpmac_node))
> + of_node_put(to_of_node(dpmac_node));
>
> return 0;
>
> err_phylink_destroy:
> phylink_destroy(mac->phylink);
> err_put_node:
> - of_node_put(dpmac_node);
> + if (is_of_node(dpmac_node))
> + of_node_put(to_of_node(dpmac_node));
> err_close_dpmac:
> dpmac_close(mac->mc_io, 0, dpmac_dev->mc_handle);
> return err;
> --
> 2.17.1
>
>

--
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