[cadcdev-svn-commits] [SCM] branch master updated. v2.0.0-1198-g8d98948

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- Log -----------------------------------------------------------------
commit 8d98948f2b6dfc9aedd8a1edd6fb209f300403ff
Author: Falco Girgis <gyr...@gm...>
Date:   Mon Dec 4 06:34:31 2023 -0600

    RTC Date/Time Fix for Negative Unix Timestamps (#394)
    
    * First attempt at making RTC driver robust
    - Fixing time_t over/underflow for RTC API
    - Moved a bunch of private stuff that was polluting the global API into
      the .c file
    - Fixed up documentation in a few places, added more info on error
      conditions
    
    * Fixed all issues with date/time negatives/overflow
    - Had a precision issue with getting the current unix seconds where a
      subtraction that should've been done on an int64_t was done on a
    uint32_t, freaking out upon negatives
    - Had a precision issue with setting the current unix seconds where the
      updated boot time did a similar subtraction which got truncated as a
    uint32_t rather than an int64_t

commit 036af84aa28358763ab2e4ee123755ba4b2cd902
Author: Falco Girgis <gyr...@gm...>
Date:   Sun Dec 3 23:22:10 2023 -0600

    Doxygen GitHub link (#404)
    
    * Doxygen Layout Path Fix
    
    - Still wasn't the correct $(KOS_BASE) relative path.

commit a96afcc11ecf820293475df23968e6c181a4de6d
Author: Falco Girgis <gyr...@gm...>
Date:   Sun Dec 3 23:16:15 2023 -0600

    Changed Doxygen  to use $(KOS_BASE) for Navigator Layout Path (#403)
    
    * Changed Doxygen layout file to use KOS ENV path
    
    - Was previously using a relative path which would screw up depending on
      where Doxygen was run.

-----------------------------------------------------------------------

Summary of changes:
 doc/Doxyfile                             |  2 +-
 kernel/arch/dreamcast/include/arch/rtc.h | 49 +++-----------------
 kernel/arch/dreamcast/kernel/rtc.c       | 77 +++++++++++++++++++++++++++-----
 3 files changed, 73 insertions(+), 55 deletions(-)

diff --git a/doc/Doxyfile b/doc/Doxyfile
index 2f7c77a..290d332 100644
--- a/doc/Doxyfile
+++ b/doc/Doxyfile
@@ -786,7 +786,7 @@ FILE_VERSION_FILTER    =
 # DoxygenLayout.xml, doxygen will parse it automatically even if the LAYOUT_FILE
 # tag is left empty.
 
-LAYOUT_FILE            = pages/DoxygenLayout.xml
+LAYOUT_FILE            = $(KOS_BASE)/doc/pages/DoxygenLayout.xml
 
 # The CITE_BIB_FILES tag can be used to specify one or more bib files containing
 # the reference definitions. This must be a list of .bib files. The .bib
diff --git a/kernel/arch/dreamcast/include/arch/rtc.h b/kernel/arch/dreamcast/include/arch/rtc.h
index a68f7cf..9951cf4 100644
--- a/kernel/arch/dreamcast/include/arch/rtc.h
+++ b/kernel/arch/dreamcast/include/arch/rtc.h
@@ -59,48 +59,6 @@ __BEGIN_DECLS
     \sa wdt
 */
 
-/** \defgroup rtc_regs Registers
-    \brief    RTC registers
-    \ingroup  rtc
-
-    All registers are located on the G2 BUS and must be read and
-    written to as full 32-byte values.
-@{*/
-
-/** \brief High 16-bit timestamp value
-
-    32-bit register containing the upper 16-bits of
-    the 32-bit timestamp in seconds. Only the lower 16-bits
-    are valid.
-
-    \note Writing to this register will lock the timestamp registers.
- */
-#define RTC_TIMESTAMP_HIGH_ADDR   0xa0710000
-
-/** \brief Low 16-bit timestamp value
-
-    32-bit register containing the lower 16-bits of
-    the 32-bit timestamp in seconds. Only the lower 16-bits
-    are valid.
- */
-#define RTC_TIMESTAMP_LOW_ADDR    0xa0710004
-
-/** \brief Timestamp control register
-
-    All fields are reserved except for #RTC_CTRL_WRITE_EN,
-    which is write-only.
- */
-#define RTC_CTRL_ADDR             0xa0710008
-/**
-@} */
-
-/** \brief Timestamp write enable
-
-    #RTC_CTRL_ADDR value to be written in order to unlock
-    writing to the timestamp registers.
-*/
-#define RTC_CTRL_WRITE_EN         (1 << 0)
-
 /** \brief   Get the current date/time.
     \ingroup rtc
 
@@ -114,13 +72,18 @@ __BEGIN_DECLS
 */
 time_t rtc_unix_secs(void);
 
-/** \brief   Get the current date/time.
+/** \brief   Set the current date/time.
     \ingroup rtc
 
     This function sets the current RTC value as a standard UNIX timestamp
     (with an epoch of January 1, 1970 00:00). This is assumed to be in the
     timezone of the user (as the RTC does not support timezones).
 
+    \warning
+    This function may fail! Since `time_t` is typically 64-bit while the RTC
+    uses a 32-bit timestamp (which also has a different epoch), not all
+    `time_t` values can be represented within the RTC!
+
     \param time             Unix timestamp to set the current time to
 
     \return                 0 for success or -1 for failure
diff --git a/kernel/arch/dreamcast/kernel/rtc.c b/kernel/arch/dreamcast/kernel/rtc.c
index 53564b6..db83694 100644
--- a/kernel/arch/dreamcast/kernel/rtc.c
+++ b/kernel/arch/dreamcast/kernel/rtc.c
@@ -7,7 +7,8 @@
    Copyright (C) 2023 Megavolt85
 */
 
-/* Real-Time Clock (RTC) support
+/*
+   Real-Time Clock (RTC) Support
 
    The functions in here return various info about the real-world time and
    date stored in the machine. The general process here is to retrieve
@@ -28,16 +29,64 @@
 #include <arch/timer.h>
 #include <dc/g2bus.h>
 #include <stdint.h>
+#include <assert.h>
 
-#define RTC_UNIX_EPOCH_DELTA    631152000   /* Twenty years in seconds */
-#define RTC_RETRY_COUNT         3           /* # of times to repeat on bad access */
+/*
+    High 16-bit Timestamp Value
+
+    32-bit register containing the upper 16-bits of
+    the 32-bit timestamp in seconds. Only the lower 16-bits
+    are valid.
+
+    Writing to this register will lock the timestamp registers.
+*/
+#define RTC_TIMESTAMP_HIGH_ADDR   0xa0710000
+
+/*
+    Low 16-bit Timestamp Value
+
+    32-bit register containing the lower 16-bits of
+    the 32-bit timestamp in seconds. Only the lower 16-bits
+    are valid.
+*/
+#define RTC_TIMESTAMP_LOW_ADDR    0xa0710004
+
+/*
+    Timestamp Control Register
+
+    All fields are reserved except for RTC_CTRL_WRITE_EN,
+    which is write-only.
+*/
+#define RTC_CTRL_ADDR             0xa0710008
+
+/*
+    Timestamp Write Enable
+
+    RTC_CTRL_ADDR field to be written in order to unlock
+    writing to the timestamp registers.
+*/
+#define RTC_CTRL_WRITE_EN         (1 << 0)
+
+/*
+   Second Delta between Sega and Unix Epochs
+
+   Twenty years in seconds.
+*/
+#define RTC_UNIX_EPOCH_DELTA    631152000
+
+/*
+    # of Read/Write Retry Attempts
+
+    To ensure a coherent, race-free read/write operation.
+*/
+#define RTC_RETRY_COUNT         3
 
 /* The boot time; we'll save this in rtc_init() */
 static time_t boot_time = 0;
 
 /* Returns the date/time value as a UNIX epoch time stamp */
 time_t rtc_unix_secs(void) {
-    uint32 rtcold, rtcnew;
+    uint32_t rtcold, rtcnew;
     int i;
 
     /* Try several times to make sure we don't read one value, then the
@@ -60,10 +109,7 @@ time_t rtc_unix_secs(void) {
             break;
     }
 
-    /* Subtract out 20 years */
-    rtcnew = rtcnew - RTC_UNIX_EPOCH_DELTA;
-
-    return rtcnew;
+    return rtcnew - RTC_UNIX_EPOCH_DELTA;
 }
 
 /* Sets the date/time value from a UNIX epoch time stamp, 
@@ -72,9 +118,16 @@ int rtc_set_unix_secs(time_t secs) {
     int result = 0;
     uint32_t rtcnew;
     int i;
+    uint32_t s, ms;
 
     /* Adjust by 20 years to get to the expected RTC time. */
-    const uint32_t adjusted = secs + RTC_UNIX_EPOCH_DELTA;
+    const time_t adjusted_time = secs + RTC_UNIX_EPOCH_DELTA;
+    const uint32_t adjusted = (const uint32_t)adjusted_time;
+
+    /* Protect against underflowing or overflowing our 32-bit timestamp. */
+    if(adjusted_time < 0 || adjusted_time > UINT32_MAX)
+        return -1;
+
 
     /* Enable writing by setting LSB of control */
     g2_write_32(RTC_CTRL_ADDR, RTC_CTRL_WRITE_EN);
@@ -94,6 +147,9 @@ int rtc_set_unix_secs(time_t secs) {
             break;
     }
 
+    /* Disable further writing by clearing LSB of control */
+    g2_write_32(RTC_CTRL_ADDR, 0);
+
     /* Signify failure if the fetched time never matched the
        time we attempted to set. */
     if(i == RTC_RETRY_COUNT)
@@ -102,9 +158,8 @@ int rtc_set_unix_secs(time_t secs) {
     /* We have to update the boot time now as well, subtracting
        the amount of time that has elapsed since boot from the 
        new time we've just set. */
-    uint32 s, ms;
     timer_ms_gettime(&s, &ms);
-    boot_time = rtcnew - RTC_UNIX_EPOCH_DELTA - s;
+    boot_time = ((time_t)rtcnew - RTC_UNIX_EPOCH_DELTA) - s;
 
     return result;
 }


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