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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>
This commit is contained in:
Nimrod Andy 2014-10-15 17:30:12 +08:00 committed by David S. Miller
parent 001586a737
commit 28b5f058cf
3 changed files with 56 additions and 42 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

50
drivers/net/ethernet/freescale/fec.h
View File

@ -367,6 +367,56 @@ struct bufdesc_ex {
#define FEC_VLAN_TAG_LEN 0x04
#define FEC_ETHTYPE_LEN 0x02
/* 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)
/* ENET Block Guide/ Chapter for the iMX6SX (PELE) address one 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. The 1588 ts_clk is fixed to 25Mhz,
* register clock is 66Mhz, so the wait-time-cycles must be greater than 240ns
* (40ns * 6).
*/
#define FEC_QUIRK_BUG_CAPTURE (1 << 10)
struct fec_enet_priv_tx_q {
int index;
unsigned char *tx_bounce[TX_RING_SIZE];

43
drivers/net/ethernet/freescale/fec_main.c
View File

@ -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 */
}

5
drivers/net/ethernet/freescale/fec_ptp.c
View File

@ -236,12 +236,17 @@ static cycle_t fec_ptp_read(const struct cyclecounter *cc)
{
struct fec_enet_private *fep =
container_of(cc, struct fec_enet_private, cc);
const struct platform_device_id *id_entry =
platform_get_device_id(fep->pdev);
u32 tempval;
tempval = readl(fep->hwp + FEC_ATIME_CTRL);
tempval |= FEC_T_CTRL_CAPTURE;
writel(tempval, fep->hwp + FEC_ATIME_CTRL);
if (id_entry->driver_data & FEC_QUIRK_BUG_CAPTURE)
udelay(1);
return readl(fep->hwp + FEC_ATIME);
}