gianfar: Add missing graceful reset steps and fixes

gfar_halt() and gfar_start() are responsible for stopping
and starting the DMA and the Rx/Tx hw rings. They implement
the support for the "graceful Rx/Tx stop/start" hw procedure,
and also disable/enable eTSEC's hw interrupts in the process.

The GRS/GTS procedure requires however to have the RQUEUE/TQUEUE
registers cleared first and to wait for a period of time for the
current frame to pass through the interface (around ~10ms for a
jumbo frame). Only then may the GTS and GRS bits from DMACTRL be
set to shut down the DMA, and finally the Tx_EN and Rx_EN bits in
MACCFG1 may be cleared to disable the Tx/Rx blocks.

The same register programming order applies to start the Rx/Tx:
enabling the RQUEUE/TQUEUE *before* clearing the GRS/GTS bits.

This is a HW recommendation in order to avoid a possible
controller "lock up" during graceful reset.

Cleanup the gfar_halt()/start() prototypes, to take priv instead
of ndev as their purpose is to operate on HW. Enabling the
RQUEUE/TQUEUE in the hw_init() is not needed anymore since
that's the job of gfar_start().

Signed-off-by: Claudiu Manoil <claudiu.manoil@freescale.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 1 deletions

diff --git a/drivers/net/ethernet/freescale/gianfar.h b/drivers/net/ethernet/freescale/gianfar.h
index 53e34662b90e..2a59398f8cf0 100644
--- a/drivers/net/ethernet/freescale/gianfar.h
+++ b/drivers/net/ethernet/freescale/gianfar.h
@@ -1205,7 +1205,8 @@ void unlock_tx_qs(struct gfar_private *priv);
 irqreturn_t gfar_receive(int irq, void *dev_id);
 int startup_gfar(struct net_device *dev);
 void stop_gfar(struct net_device *dev);
-void gfar_halt(struct net_device *dev);
+void gfar_halt(struct gfar_private *priv);
+void gfar_start(struct gfar_private *priv);
 void gfar_phy_test(struct mii_bus *bus, struct phy_device *phydev, int enable,
 		   u32 regnum, u32 read);
 void gfar_configure_coalescing_all(struct gfar_private *priv);