kernel: sfp: re-attempt probing for phy

Add patches retrying to probe the PHY to restore support for PHYs taking
longer to initialize without breaking modules without PHYs.

Patches taken from http://git.armlinux.org.uk/cgit/linux-arm.git/log/?h=phy

Signed-off-by: Jonas Gorski <jonas.gorski@gmail.com>

1 files changed, 55 insertions, 0 deletions

diff --git a/target/linux/generic/pending-4.19/756-net-sfp-use-a-definition-for-the-fault-recovery-atte.patch b/target/linux/generic/pending-4.19/756-net-sfp-use-a-definition-for-the-fault-recovery-atte.patch
new file mode 100644
index 0000000000..0e5005ed19
--- /dev/null
+++ b/target/linux/generic/pending-4.19/756-net-sfp-use-a-definition-for-the-fault-recovery-atte.patch
@@ -0,0 +1,55 @@
+From 4d6bfb6fbb00af38402db4d1ce464e22def9fd9e Mon Sep 17 00:00:00 2001
+From: Russell King <rmk+kernel@armlinux.org.uk>
+Date: Thu, 28 Nov 2019 14:24:40 +0000
+Subject: [PATCH 1/4] net: sfp: use a definition for the fault recovery
+ attempts
+
+Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
+---
+ drivers/net/phy/sfp.c | 14 +++++++++++---
+ 1 file changed, 11 insertions(+), 3 deletions(-)
+
+--- a/drivers/net/phy/sfp.c
++++ b/drivers/net/phy/sfp.c
+@@ -160,6 +160,14 @@ static const enum gpiod_flags gpio_flags
+ #define T_RESET_US	10
+ #define T_FAULT_RECOVER	msecs_to_jiffies(1000)
+ 
++/* N_FAULT_INIT is the number of recovery attempts at module initialisation
++ * time. If the TX_FAULT signal is not deasserted after this number of
++ * attempts at clearing it, we decide that the module is faulty.
++ * N_FAULT is the same but after the module has initialised.
++ */
++#define N_FAULT_INIT		5
++#define N_FAULT			5
++
+ /* SFP module presence detection is poor: the three MOD DEF signals are
+  * the same length on the PCB, which means it's possible for MOD DEF 0 to
+  * connect before the I2C bus on MOD DEF 1/2.
+@@ -1803,7 +1811,7 @@ static void sfp_sm_main(struct sfp *sfp,
+ 		sfp_module_tx_enable(sfp);
+ 
+ 		/* Initialise the fault clearance retries */
+-		sfp->sm_retries = 5;
++		sfp->sm_retries = N_FAULT_INIT;
+ 
+ 		/* We need to check the TX_FAULT state, which is not defined
+ 		 * while TX_DISABLE is asserted. The earliest we want to do
+@@ -1842,7 +1850,7 @@ static void sfp_sm_main(struct sfp *sfp,
+ 			 * there is a fault.
+ 			 */
+ 			sfp_sm_fault(sfp, SFP_S_INIT_TX_FAULT,
+-				     sfp->sm_retries == 5);
++				     sfp->sm_retries == N_FAULT_INIT);
+ 		} else if (event == SFP_E_TIMEOUT || event == SFP_E_TX_CLEAR) {
+ 	init_done:	/* TX_FAULT deasserted or we timed out with TX_FAULT
+ 			 * clear.  Probe for the PHY and check the LOS state.
+@@ -1855,7 +1863,7 @@ static void sfp_sm_main(struct sfp *sfp,
+ 			sfp_sm_link_check_los(sfp);
+ 
+ 			/* Reset the fault retry count */
+-			sfp->sm_retries = 5;
++			sfp->sm_retries = N_FAULT;
+ 		}
+ 		break;
+