net: fec: ptp: fix convergence issue to support LinuxPTP stack

iMX6SX IEEE 1588 module has one hw issue in capturing the ATVR register.
The current SW flow is:
		ENET0->ATCR |= ENET_ATCR_CAPTURE_MASK;
		ts_counter_ns = ENET0->ATVR;
The ATVR value is not expected value that cause LinuxPTP stack cannot be convergent.

ENET Block Guide/ Chapter for the iMX6SX (PELE) address the issue:
After set ENET_ATCR[Capture], there need some time cycles before the counter
value is capture in the register clock domain. The wait-time-cycles is at least
6 clock cycles of the slower clock between the register clock and the 1588 clock.
So need something like:
		ENET0->ATCR |= ENET_ATCR_CAPTURE_MASK;
		wait();
		ts_counter_ns = ENET0->ATVR;

For iMX6SX, the 1588 ts_clk is fixed to 25Mhz, register clock is 66Mhz, so the
wait-time-cycles must be greater than 240ns (40ns * 6). The patch add 1us delay
before cpu read ATVR register.

Changes V2:
Modify the commit/comments log to describe the issue clearly.

Signed-off-by: Fugang Duan <B38611@freescale.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 1 insertions, 42 deletions

diff --git a/drivers/net/ethernet/freescale/fec_main.c b/drivers/net/ethernet/freescale/fec_main.c
index e364d1fc7bdc..81b96cf87574 100644
--- a/drivers/net/ethernet/freescale/fec_main.c
+++ b/drivers/net/ethernet/freescale/fec_main.c
@@ -78,47 +78,6 @@ static void fec_enet_itr_coal_init(struct net_device *ndev);
 #define FEC_ENET_RAFL_V	0x8
 #define FEC_ENET_OPD_V	0xFFF0
 
-/* Controller is ENET-MAC */
-#define FEC_QUIRK_ENET_MAC		(1 << 0)
-/* Controller needs driver to swap frame */
-#define FEC_QUIRK_SWAP_FRAME		(1 << 1)
-/* Controller uses gasket */
-#define FEC_QUIRK_USE_GASKET		(1 << 2)
-/* Controller has GBIT support */
-#define FEC_QUIRK_HAS_GBIT		(1 << 3)
-/* Controller has extend desc buffer */
-#define FEC_QUIRK_HAS_BUFDESC_EX	(1 << 4)
-/* Controller has hardware checksum support */
-#define FEC_QUIRK_HAS_CSUM		(1 << 5)
-/* Controller has hardware vlan support */
-#define FEC_QUIRK_HAS_VLAN		(1 << 6)
-/* ENET IP errata ERR006358
- *
- * If the ready bit in the transmit buffer descriptor (TxBD[R]) is previously
- * detected as not set during a prior frame transmission, then the
- * ENET_TDAR[TDAR] bit is cleared at a later time, even if additional TxBDs
- * were added to the ring and the ENET_TDAR[TDAR] bit is set. This results in
- * frames not being transmitted until there is a 0-to-1 transition on
- * ENET_TDAR[TDAR].
- */
-#define FEC_QUIRK_ERR006358            (1 << 7)
-/* ENET IP hw AVB
- *
- * i.MX6SX ENET IP add Audio Video Bridging (AVB) feature support.
- * - Two class indicators on receive with configurable priority
- * - Two class indicators and line speed timer on transmit allowing
- *   implementation class credit based shapers externally
- * - Additional DMA registers provisioned to allow managing up to 3
- *   independent rings
- */
-#define FEC_QUIRK_HAS_AVB		(1 << 8)
-/* There is a TDAR race condition for mutliQ when the software sets TDAR
- * and the UDMA clears TDAR simultaneously or in a small window (2-4 cycles).
- * This will cause the udma_tx and udma_tx_arbiter state machines to hang.
- * The issue exist at i.MX6SX enet IP.
- */
-#define FEC_QUIRK_ERR007885		(1 << 9)
-
 static struct platform_device_id fec_devtype[] = {
 	{
 		/* keep it for coldfire */
@@ -146,7 +105,7 @@ static struct platform_device_id fec_devtype[] = {
 		.driver_data = FEC_QUIRK_ENET_MAC | FEC_QUIRK_HAS_GBIT |
 				FEC_QUIRK_HAS_BUFDESC_EX | FEC_QUIRK_HAS_CSUM |
 				FEC_QUIRK_HAS_VLAN | FEC_QUIRK_HAS_AVB |
-				FEC_QUIRK_ERR007885,
+				FEC_QUIRK_ERR007885 | FEC_QUIRK_BUG_CAPTURE,
 	}, {
 		/* sentinel */
 	}