[PATCH v2] net: mtk_sgmii: implement mtk_pcs_ops

[Frank Wunderlich <linux@fw-web.de>]

From: Alexander Couzens <lynxis@fe80.eu>

Implement mtk_pcs_ops for the SGMII pcs to read the current state
of the hardware.

Signed-off-by: Alexander Couzens <lynxis@fe80.eu>
Signed-off-by: Frank Wunderlich <frank-w@public-files.de>

Fixes: 14a44ab0330d ("net: mtk_eth_soc: partially convert to phylink_pcs")
---
v2:
- reorder members in phylink_pcs_ops
- drop pause setting

without this Patch i get this trace in 6.1-rc1 when enabling the left
sfp (eth1) on bpi-r3 (crash happens in phylink core because a NULL-pointer,
so fixes-Tag is a guess):

[  108.302810] Unable to handle kernel execute from non-executable memory at virtual address 0000000000000000
[  108.312462] Mem abort info:
[  108.315263]   ESR = 0x0000000086000005
[  108.319003]   EC = 0x21: IABT (current EL), IL = 32 bits
[  108.324335]   SET = 0, FnV = 0
[  108.327378]   EA = 0, S1PTW = 0
[  108.330505]   FSC = 0x05: level 1 translation fault
[  108.335375] user pgtable: 4k pages, 39-bit VAs, pgdp=00000000419be000
[  108.341798] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000, pu
d=0000000000000000
[  108.350489] Internal error: Oops: 0000000086000005 [#1] SMP
[  108.356047] Modules linked in: cdc_mbim cdc_ncm cdc_wdm cdc_ether qcserial us
a_wwan usbnet usbser
a Mmeisis
ge from syslogd@bpi-r3 at Aug  7 15:26:54 ...
 kernel:[  108.350489] Internal error: Oops: 0000000086000005 [#1] SMP
[  108.376743] CPU: 3 PID: 8 Comm: kworker/u8:0 Not tainted 6.0.0-bpi-r3 #1
[  108.383461] Hardware name: Bananapi BPI-R3 (sdmmc) (DT)
[  108.388671] Workqueue: events_power_efficient phylink_resolve
[  108.394411] pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
[  108.401355] pc : 0x0
[  108.403531] lr : phylink_mac_pcs_get_state+0x7c/0x100
[  108.408572] sp : ffffffc00963bd00
[  108.411873] x29: ffffffc00963bd00 x28: 0000000000000000 x27: 0000000000000000
[  108.418994] x26: ffffff80000ed074 x25: ffffff800001c105 x24: 0000000000000000
[  108.426116] x23: ffffff80022f8cd8 x22: ffffff80022f8d30 x21: ffffff80022f8c00
[  108.433236] x20: 0000000000000000 x19: ffffff8000126040 x18: 0000000000000000
[  108.440357] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
[  108.447478] x14: ffffffffffffffff x13: 0000000000000030 x12: 0101010101010101
[  108.454598] x11: 7f7f7f7f7f7f7f7f x10: fefefefefefefeff x9 : ffffff80000ed07c
[  108.461720] x8 : fefefefefefefeff x7 : 0000000000000017 x6 : ffffff80000ed074
[  108.468840] x5 : 0000000000000000 x4 : 0000020000006440 x3 : 00000000fffffffa
[  108.475960] x2 : 0000000000000000 x1 : ffffffc00963bd80 x0 : ffffff80014c3ab0
[  108.483082] Call trace:
[  108.485516]  0x0
[  108.487344]  phylink_resolve+0x248/0x520
[  108.491256]  process_one_work+0x204/0x478
[  108.495256]  worker_thread+0x148/0x4c0
[  108.498993]  kthread+0xdc/0xe8
[  108.502037]  ret_from_fork+0x10/0x20
[  108.505608] Code: bad PC value
[  108.508652] ---[ end trace 0000000000000000 ]---
[  108.513255] Kernel panic - not syncing: Oops: Fatal exception
[  108.518984] SMP: stopping secondary CPUs
[  108.522894] Kernel Offset: disabled
[  108.526369] CPU features: 0x00000,00800084,0000420b
[  108.531232] Memory Limit: none
[  108.534274] Rebooting in 1 seconds..
---
 drivers/net/ethernet/mediatek/mtk_sgmii.c | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/drivers/net/ethernet/mediatek/mtk_sgmii.c b/drivers/net/ethernet/mediatek/mtk_sgmii.c
index 736839c84130..8b7465057e57 100644
--- a/drivers/net/ethernet/mediatek/mtk_sgmii.c
+++ b/drivers/net/ethernet/mediatek/mtk_sgmii.c
@@ -122,7 +122,21 @@ static void mtk_pcs_link_up(struct phylink_pcs *pcs, unsigned int mode,
 	regmap_write(mpcs->regmap, SGMSYS_SGMII_MODE, val);
 }
 
+static void mtk_pcs_get_state(struct phylink_pcs *pcs, struct phylink_link_state *state)
+{
+	struct mtk_pcs *mpcs = pcs_to_mtk_pcs(pcs);
+	unsigned int val;
+
+	regmap_read(mpcs->regmap, mpcs->ana_rgc3, &val);
+	state->speed = val & RG_PHY_SPEED_3_125G ? SPEED_2500 : SPEED_1000;
+
+	regmap_read(mpcs->regmap, SGMSYS_PCS_CONTROL_1, &val);
+	state->an_complete = !!(val & SGMII_AN_COMPLETE);
+	state->link = !!(val & SGMII_LINK_STATYS);
+}
+
 static const struct phylink_pcs_ops mtk_pcs_ops = {
+	.pcs_get_state = mtk_pcs_get_state,
 	.pcs_config = mtk_pcs_config,
 	.pcs_an_restart = mtk_pcs_restart_an,
 	.pcs_link_up = mtk_pcs_link_up,
-- 
2.34.1