faster i2c for eeprom

On VFC-HD reading EEPROM was taking too long. E.g. reading SFP database through snmp was taking ~0.5s which was enough to break the timestamps for received PTP frames and thus the timing. See issue 1649 in wr-cores project on OHWR.

faster i2c for eeprom
On VFC-HD reading EEPROM was taking too long. E.g. reading SFP database through snmp was taking ~0.5s which was enough to break the timestamps for received PTP frames and thus the timing. See issue 1649 in wr-cores project on OHWR.
44c37218 · Grzegorz Daniluk · b5fbea63 · 44c37218 · 44c37218 · 44c37218
Commit 44c37218 authored Dec 01, 2017 by Grzegorz Daniluk
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Showing with 10 additions and 9 deletions

i2c.c dev/i2c.c +4 -6

syscon.c dev/syscon.c +2 -2

i2c.h include/i2c.h +1 -1

syscon.h include/syscon.h +3 -0

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--- a/dev/i2c.c
+++ b/dev/i2c.c
@@ -12,17 +12,15 @@
 #include "syscon.h"
 #include "i2c.h"

-#define I2C_DELAY 300
-
-void mi2c_delay(void)
+void mi2c_delay(uint32_t delay)
 {
 	int i;
-	for (i = 0; i < I2C_DELAY; i++)
+	for (i = 0; i < delay; i++)
 		asm volatile ("nop");
 }

-#define M_SDA_OUT(i, x) { gpio_out(i2c_if[i].sda, x); mi2c_delay(); }
-#define M_SCL_OUT(i, x) { gpio_out(i2c_if[i].scl, x); mi2c_delay(); }
+#define M_SDA_OUT(i, x) { gpio_out(i2c_if[i].sda, x); mi2c_delay(i2c_if[i].loop_delay); }
+#define M_SCL_OUT(i, x) { gpio_out(i2c_if[i].scl, x); mi2c_delay(i2c_if[i].loop_delay); }
 #define M_SDA_IN(i) gpio_in(i2c_if[i].sda)

 void mi2c_start(uint8_t i2cif)

--- a/dev/syscon.c
+++ b/dev/syscon.c
@@ -11,8 +11,8 @@
 #include <string.h>

 struct s_i2c_if i2c_if[2] = {
-	{SYSC_GPSR_FMC_SCL, SYSC_GPSR_FMC_SDA},
-	{SYSC_GPSR_SFP_SCL, SYSC_GPSR_SFP_SDA}
+	{SYSC_GPSR_FMC_SCL, SYSC_GPSR_FMC_SDA, FMC_I2C_DELAY},
+	{SYSC_GPSR_SFP_SCL, SYSC_GPSR_SFP_SDA, SFP_I2C_DELAY}
 };

 volatile struct SYSCON_WB *syscon;

--- a/include/i2c.h
+++ b/include/i2c.h
@@ -14,7 +14,7 @@ void mi2c_stop(uint8_t i2cif);
 void mi2c_get_byte(uint8_t i2cif, unsigned char *data, uint8_t last);
 unsigned char mi2c_put_byte(uint8_t i2cif, unsigned char data);

-void mi2c_delay(void);
+void mi2c_delay(uint32_t delay);
 //void mi2c_scan(uint8_t i2cif);

 #endif
--- a/include/syscon.h
+++ b/include/syscon.h
@@ -91,10 +91,13 @@ struct SYSCON_WB {

 #define WRPC_FMC_I2C  0
 #define WRPC_SFP_I2C  1
+#define FMC_I2C_DELAY 15
+#define SFP_I2C_DELAY 300

 struct s_i2c_if {
 	uint32_t scl;
 	uint32_t sda;
+	uint32_t loop_delay;
 };

 extern struct s_i2c_if i2c_if[2];