iPod Classic: prepare i2c and PMU for bootloader

When the bootloader starts only IRAM is available, the first task is to
ask the PMU to verify if the iPod has previously been hibernated by OF.
Due to memory limitations, the kernel cannot be used on this stage.

This patch modifies I2C and PMU low level functions to not to depend
on kernel (removes mutexes, and uses HW timer instead of current_tick),
actual kernel functions are modified to be 'mutexed' wrappers of the new
functions.

Change-Id: I7cef9e95dedaf176dc0659315f3dc33166d5b116

4 files changed, 73 insertions, 53 deletions

diff --git a/firmware/export/i2c-s5l8702.h b/firmware/export/i2c-s5l8702.h
index 02dc40d89e..3883c8abc0 100644
--- a/firmware/export/i2c-s5l8702.h
+++ b/firmware/export/i2c-s5l8702.h
@@ -28,5 +28,9 @@ void i2c_init(void);
 int i2c_write(int bus, unsigned char slave, int address, int len, const unsigned char *data);
 int i2c_read(int bus, unsigned char slave, int address, int len, unsigned char *data);
 
-#endif /* _I2C_S5l8702_H */
+#ifdef BOOTLOADER
+int i2c_wr(int bus, unsigned char slave, int address, int len, const unsigned char *data);
+int i2c_rd(int bus, unsigned char slave, int address, int len, unsigned char *data);
+#endif
 
+#endif /* _I2C_S5l8702_H */
diff --git a/firmware/target/arm/s5l8702/i2c-s5l8702.c b/firmware/target/arm/s5l8702/i2c-s5l8702.c
index 4d0e4188ab..619768410a 100644
--- a/firmware/target/arm/s5l8702/i2c-s5l8702.c
+++ b/firmware/target/arm/s5l8702/i2c-s5l8702.c
@@ -18,7 +18,7 @@
  * KIND, either express or implied.
  *
  ****************************************************************************/
- 
+
 #include "config.h"
 #include "system.h"
 #include "kernel.h"
@@ -71,68 +71,52 @@ void i2c_init()
     mutex_init(&i2c_mtx[1]);
 }
 
-int i2c_write(int bus, unsigned char slave, int address, int len, const unsigned char *data)
+int i2c_wr(int bus, unsigned char slave, int address, int len, const unsigned char *data)
 {
-    mutex_lock(&i2c_mtx[bus]);
     i2c_on(bus);
-    long timeout = current_tick + HZ / 50;
+    long timeout = USEC_TIMER + 20000;
 
     /* START */
     IICDS(bus) = slave & ~1;
     IICSTAT(bus) = 0xF0;
     IICCON(bus) = 0xB3;
     while ((IICCON(bus) & 0x10) == 0)
-        if (TIME_AFTER(current_tick, timeout))
-        {
-            mutex_unlock(&i2c_mtx[bus]);
+        if (TIME_AFTER(USEC_TIMER, timeout))
             return 1;
-        }
 
-    
     if (address >= 0) {
         /* write address */
         IICDS(bus) = address;
         IICCON(bus) = 0xB3;
         while ((IICCON(bus) & 0x10) == 0)
-            if (TIME_AFTER(current_tick, timeout))
-            {
-                mutex_unlock(&i2c_mtx[bus]);
+            if (TIME_AFTER(USEC_TIMER, timeout))
                 return 2;
-            }
     }
-    
+
     /* write data */
     while (len--) {
         IICDS(bus) = *data++;
         IICCON(bus) = 0xB3;
         while ((IICCON(bus) & 0x10) == 0)
-            if (TIME_AFTER(current_tick, timeout))
-            {
-                mutex_unlock(&i2c_mtx[bus]);
+            if (TIME_AFTER(USEC_TIMER, timeout))
                 return 4;
-            }
     }
 
     /* STOP */
     IICSTAT(bus) = 0xD0;
     IICCON(bus) = 0xB3;
     while ((IICSTAT(bus) & (1 << 5)) != 0)
-        if (TIME_AFTER(current_tick, timeout))
-        {
-            mutex_unlock(&i2c_mtx[bus]);
+        if (TIME_AFTER(USEC_TIMER, timeout))
             return 5;
-        }
-    
+
     i2c_off(bus);
-    mutex_unlock(&i2c_mtx[bus]);
     return 0;
 }
 
-int i2c_read(int bus, unsigned char slave, int address, int len, unsigned char *data)
+int i2c_rd(int bus, unsigned char slave, int address, int len, unsigned char *data)
 {
-    mutex_lock(&i2c_mtx[bus]);
     i2c_on(bus);
-    long timeout = current_tick + HZ / 50;
+    long timeout = USEC_TIMER + 20000;
 
     if (address >= 0) {
         /* START */
@@ -140,42 +124,30 @@ int i2c_read(int bus, unsigned char slave, int address, int len, unsigned char *
         IICSTAT(bus) = 0xF0;
         IICCON(bus) = 0xB3;
         while ((IICCON(bus) & 0x10) == 0)
-            if (TIME_AFTER(current_tick, timeout))
-            {
-                mutex_unlock(&i2c_mtx[bus]);
+            if (TIME_AFTER(USEC_TIMER, timeout))
                 return 1;
-            }
 
         /* write address */
         IICDS(bus) = address;
         IICCON(bus) = 0xB3;
         while ((IICCON(bus) & 0x10) == 0)
-            if (TIME_AFTER(current_tick, timeout))
-            {
-                mutex_unlock(&i2c_mtx[bus]);
+            if (TIME_AFTER(USEC_TIMER, timeout))
                 return 2;
-            }
     }
-    
+
     /* (repeated) START */
     IICDS(bus) = slave | 1;
     IICSTAT(bus) = 0xB0;
     IICCON(bus) = 0xB3;
     while ((IICCON(bus) & 0x10) == 0)
-        if (TIME_AFTER(current_tick, timeout))
-        {
-            mutex_unlock(&i2c_mtx[bus]);
+        if (TIME_AFTER(USEC_TIMER, timeout))
             return 3;
-        }
-    
+
     while (len--) {
         IICCON(bus) = (len == 0) ? 0x33 : 0xB3; /* NAK or ACK */
         while ((IICCON(bus) & 0x10) == 0)
-            if (TIME_AFTER(current_tick, timeout))
-            {
-                mutex_unlock(&i2c_mtx[bus]);
+            if (TIME_AFTER(USEC_TIMER, timeout))
                 return 4;
-            }
         *data++ = IICDS(bus);
     }
 
@@ -183,14 +155,27 @@ int i2c_read(int bus, unsigned char slave, int address, int len, unsigned char *
     IICSTAT(bus) = 0x90;
     IICCON(bus) = 0xB3;
     while ((IICSTAT(bus) & (1 << 5)) != 0)
-        if (TIME_AFTER(current_tick, timeout))
-        {
-            mutex_unlock(&i2c_mtx[bus]);
+        if (TIME_AFTER(USEC_TIMER, timeout))
             return 5;
-        }
-    
+
     i2c_off(bus);
-    mutex_unlock(&i2c_mtx[bus]);
     return 0;
 }
 
+int i2c_write(int bus, unsigned char slave, int address, int len, const unsigned char *data)
+{
+    int ret;
+    mutex_lock(&i2c_mtx[bus]);
+    ret = i2c_wr(bus, slave, address, len, data);
+    mutex_unlock(&i2c_mtx[bus]);
+    return ret;
+}
+
+int i2c_read(int bus, unsigned char slave, int address, int len, unsigned char *data)
+{
+    int ret;
+    mutex_lock(&i2c_mtx[bus]);
+    ret = i2c_rd(bus, slave, address, len, data);
+    mutex_unlock(&i2c_mtx[bus]);
+    return ret;
+}
diff --git a/firmware/target/arm/s5l8702/ipod6g/pmu-ipod6g.c b/firmware/target/arm/s5l8702/ipod6g/pmu-ipod6g.c
index 946beb1519..2a9236046c 100644
--- a/firmware/target/arm/s5l8702/ipod6g/pmu-ipod6g.c
+++ b/firmware/target/arm/s5l8702/ipod6g/pmu-ipod6g.c
@@ -142,3 +142,27 @@ void pmu_write_rtc(unsigned char* buffer)
 {
     pmu_write_multiple(0x59, 7, buffer);
 }
+
+#ifdef BOOTLOADER
+int pmu_rd_multiple(int address, int count, unsigned char* buffer)
+{
+    return i2c_rd(0, 0xe6, address, count, buffer);
+}
+
+int pmu_wr_multiple(int address, int count, unsigned char* buffer)
+{
+    return i2c_wr(0, 0xe6, address, count, buffer);
+}
+
+unsigned char pmu_rd(int address)
+{
+    unsigned char val;
+    pmu_rd_multiple(address, 1, &val);
+    return val;
+}
+
+int pmu_wr(int address, unsigned char val)
+{
+    return pmu_wr_multiple(address, 1, &val);
+}
+#endif /* BOOTLOADER */
diff --git a/firmware/target/arm/s5l8702/ipod6g/pmu-target.h b/firmware/target/arm/s5l8702/ipod6g/pmu-target.h
index 94fd17010b..3a90ad8789 100644
--- a/firmware/target/arm/s5l8702/ipod6g/pmu-target.h
+++ b/firmware/target/arm/s5l8702/ipod6g/pmu-target.h
@@ -25,7 +25,7 @@
 #include <stdbool.h>
 #include "config.h"
 
-#include <pcf5063x.h>
+#include "pcf5063x.h"
 
 /* undocummented PMU registers */
 #define PCF50635_REG_INT6        0x85
@@ -77,4 +77,11 @@ void pmu_read_rtc(unsigned char* buffer);
 void pmu_write_rtc(unsigned char* buffer);
 void pmu_hdd_power(bool on);
 
+#ifdef BOOTLOADER
+unsigned char pmu_rd(int address);
+int pmu_wr(int address, unsigned char val);
+int pmu_rd_multiple(int address, int count, unsigned char* buffer);
+int pmu_wr_multiple(int address, int count, unsigned char* buffer);
 #endif
+
+#endif /* __PMU_TARGET_H__ */