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net/ethernet/freescale: rework quiesce/activate for ucc_geth 

ugeth_quiesce/activate are used to halt the controller when there is a
link change that requires to reconfigure the mac.

The previous implementation called netif_device_detach(). This however
causes the initial activation of the netdevice to fail precisely because
it's detached. For details, see [1].

A possible workaround was the revert of commit
net: linkwatch: add check for netdevice being present to linkwatch_do_dev
However, the check introduced in the above commit is correct and shall be
kept.

The netif_device_detach() is thus replaced with
netif_tx_stop_all_queues() that prevents any tranmission. This allows to
perform mac config change required by the link change, without detaching
the corresponding netdevice and thus not preventing its initial
activation.

[1] https://lists.openwall.net/netdev/2020/01/08/201

Signed-off-by: Valentin Longchamp <valentin@longchamp.me>
Acked-by: Matteo Ghidoni <matteo.ghidoni@ch.abb.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Valentin Longchamp 2020-05-20 17:53:50 +02:00 committed by David S. Miller
parent d3e8e4c118
commit 79dde73cf9
1 changed files with 7 additions and 6 deletions
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13
drivers/net/ethernet/freescale/ucc_geth.c
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@ -42,6 +42,7 @@
#include <soc/fsl/qe/ucc.h>
#include <soc/fsl/qe/ucc_fast.h>
#include <asm/machdep.h>
#include <net/sch_generic.h>
#include "ucc_geth.h"
@ -1548,11 +1549,8 @@ static int ugeth_disable(struct ucc_geth_private *ugeth, enum comm_dir mode)
static void ugeth_quiesce(struct ucc_geth_private *ugeth)
{
/* Prevent any further xmits, plus detach the device. */
netif_device_detach(ugeth->ndev);
/* Wait for any current xmits to finish. */
netif_tx_disable(ugeth->ndev);
/* Prevent any further xmits */
netif_tx_stop_all_queues(ugeth->ndev);
/* Disable the interrupt to avoid NAPI rescheduling. */
disable_irq(ugeth->ug_info->uf_info.irq);
@ -1565,7 +1563,10 @@ static void ugeth_activate(struct ucc_geth_private *ugeth)
{
napi_enable(&ugeth->napi);
enable_irq(ugeth->ug_info->uf_info.irq);
netif_device_attach(ugeth->ndev);
/* allow to xmit again */
netif_tx_wake_all_queues(ugeth->ndev);
__netdev_watchdog_up(ugeth->ndev);
}
/* Called every time the controller might need to be made