Re: [linuxsh-dev] Today's addition

[<pi...@li...>]

Hello Niibe-San and everybody

NIIBE Yutaka wrote:

> To compare the behavior (of SH-4), I worked for SH7709A (in the
> office).  It's another SolutionEngine.  It also failed with RAMDISK
> support (like SH-4).
>
> In my home, SH7708 works fine (with no RAMDISK), RAMDISK may be the
> cause.

Speaking of which ... I don't know if it has anything to do with it but there it goes
:

I've been working on getting the 2.3.99-pre? kernels going on Hypercom's
"WindowsCE ICE" board (which is a flavor of the P2 board from Hitachi, I understand)
for some time now : this board has a 7707 and 16M of RAM.

I had to do some modifications to the ramdisk (and the SCI and tty drivers) to get the
kernel to boot and use the SCI as initial terminal on this board :

1) In the ramdisk : it appears that the following lines in drivers/block/rd.c panic
the kernel when the kernel tries to mount the initrd filesystem :

--8<--8<--SNIP-SNIP--8<--8<--
 /*
  * Immunize device against invalidate_buffers() and prune_icache().
  */
 if (rd_inode[DEVICE_NR(inode->i_rdev)] == NULL) {
  if (!inode->i_bdev) return -ENXIO;
  if ((rd_inode[DEVICE_NR(inode->i_rdev)] = igrab(inode)) != NULL)
   atomic_inc(&rd_inode[DEVICE_NR(inode->i_rdev)]->i_bdev->bd_openers);
 }
--8<--8<--SNIP-SNIP--8<--8<--

If I comment out these lines, the ramdisk works just fine. They seem to have been
added to the kernel fairly recently so I doubt they have been exercised a lot yet.

2) In drivers/char/tty_io.c : the SCI driver doesn't get registered when trying to use
it as initial console, so I had to add several lines to get it registered explicitely.
Here is the patch :

--8<--8<--SNIP-SNIP--8<--8<--
diff -ruN linux_ORIG/drivers/char/tty_io.c linux_PATCHED/drivers/char/tty_io.c
--- linux_ORIG/drivers/char/tty_io.c Tue Mar 21 14:04:53 2000
+++ linux_PATCHED/drivers/char/tty_io.c Fri Mar 31 16:13:53 2000
@@ -141,6 +141,11 @@
 #ifdef CONFIG_SX
 extern int sx_init (void);
 #endif
+#ifdef CONFIG_SH_SCI_SERIAL
+extern int sci_init (void);
+#endif
 #if defined(CONFIG_MVME162_SCC) || defined(CONFIG_BVME6000_SCC) ||
defined(CONFIG_MVME147_SCC)
 extern int vme_scc_init (void);
 extern long vme_scc_console_init(void);
@@ -2317,6 +2322,11 @@
 #ifdef CONFIG_SX
  sx_init();
 #endif
+#ifdef CONFIG_SH_SCI_SERIAL
+sci_init();
+#endif
 #ifdef CONFIG_RIO
  rio_init();
 #endif
--8<--8<--SNIP-SNIP--8<--8<--

3) In driver/char/sh-sci.c and driver/char/sh-sci.h : the driver assumes a bus clock
speed of 14 Mhz. The board I'm working on has a bus clock speed of 30 Mhz, which
changes all the timing values for the SCI clock. So, I modified the table and the code
to use both timing counter values and clock sources, so that the range of baudrates is
higher. Also, I've added a small bit of code to set the baud rate in
serial_console_setup(), otherwise the baud rate is not set when using the SCI as
initial console. Here is the diff :

--8<--8<--SNIP-SNIP--8<--8<--
diff -ruN linux_ORIG/drivers/char/sh-sci.c linux_PATCHED/drivers/char/sh-sci.c
--- linux_ORIG/drivers/char/sh-sci.c Mon May  1 10:55:09 2000
+++ linux_PATCHED/drivers/char/sh-sci.c Tue Apr 25 10:18:00 2000
@@ -115,37 +115,73 @@
 static void sci_set_baud(struct sci_port *port)
 {
  int t;
+/*PPC*/ int cks;

  switch (port->gs.baud) {
  case 0:
   t = -1;
   break;
+/*PPC*/
+ case 110:
+  t = BPS_110;
+  cks = CKS_BPS_110;
+  break;
+ case 150:
+  t = BPS_150;
+  cks = CKS_BPS_150;
+  break;
+ case 300:
+  t = BPS_300;
+  cks = CKS_BPS_300;
+  break;
+ case 600:
+  t = BPS_600;
+  cks = CKS_BPS_600;
+  break;
+ case 1200:
+  t = BPS_1200;
+  cks = CKS_BPS_1200;
+  break;
+/*\PPC*/
  case 2400:
   t = BPS_2400;
+/*PPC*/  cks = CKS_BPS_2400;
   break;
  case 4800:
   t = BPS_4800;
+/*PPC*/  cks = CKS_BPS_4800;
   break;
  case 9600:
   t = BPS_9600;
+/*PPC*/  cks = CKS_BPS_9600;
   break;
  case 19200:
   t = BPS_19200;
+/*PPC*/  cks = CKS_BPS_19200;
   break;
  case 38400:
   t = BPS_38400;
+/*PPC*/  cks = CKS_BPS_38400;
+  break;
+/*PPC*/
+ case 57600:
+  t = BPS_57600;
+  cks = CKS_BPS_57600;
   break;
+/*\PPC*/
  default:
   printk(KERN_INFO "sci: unsupported baud rate: %d, use 115200 instead.\n",
port->gs.baud);
  case 115200:
   t = BPS_115200;
+/*PPC*/  cks = CKS_BPS_115200;
   break;
  }

  if (t > 0) {
   sci_setsignals (port, 1, -1);
   if(t >= 256) {
-   ctrl_out((ctrl_in(SCSMR) & ~3) | 1, SCSMR);
+/*PPC   ctrl_out((ctrl_in(SCSMR) & ~3) | 1, SCSMR);*/
+/*PPC*/   ctrl_out((ctrl_in(SCSMR) & ~3) | cks, SCSMR);
    t >>= 2;
   }
   ctrl_outb(t, SCBRR);
@@ -659,8 +695,10 @@
  sci_driver.type = TTY_DRIVER_TYPE_SERIAL;
  sci_driver.subtype = SERIAL_TYPE_NORMAL;
  sci_driver.init_termios = tty_std_termios;
- sci_driver.init_termios.c_cflag =
-  B115200 | CS8 | CREAD | HUPCL | CLOCAL | CRTSCTS;
+/*PPC sci_driver.init_termios.c_cflag =*/
+/*PPC  B115200 | CS8 | CREAD | HUPCL | CLOCAL | CRTSCTS;*/
+/*PPC*/ sci_driver.init_termios.c_cflag =
+/*PPC*/  SCI_DEFAULT_SPEED | CS8 | CREAD | HUPCL | CLOCAL;
  sci_driver.flags = TTY_DRIVER_REAL_RAW;
  sci_driver.refcount = &sci_refcount;
  sci_driver.table = sci_table;
@@ -747,6 +785,7 @@
 #ifdef CONFIG_DEBUG_KERNEL_WITH_GDB_STUB
  gdb_detach();
 #endif
+/*PPC*/ printk(KERN_ERR "SCI serial driver registered (major 4)\n");
  return 0;  /* Return -EIO when not detected */
 }

@@ -922,7 +961,8 @@
  */
 static int __init serial_console_setup(struct console *co, char *options)
 {
- int baud = 115200;
+/*PPC int baud = 115200;*/
+/*PPC*/ int baud = SCI_DEFAULT_SPEED_VAL;
  int bits = 8;
  int parity = 'n';
  int cflag = CREAD | HUPCL | CLOCAL;
@@ -978,6 +1018,19 @@
  co->cflag = cflag;

  /* XXX: set baud, char, and parity here. */
+/*PPC*/
+ {
+   struct termios termios;
+   struct tty_struct tty;
+   struct sci_port port;
+
+   termios.c_cflag=cflag;
+   port.gs.baud=baud;
+   tty.termios=&termios;
+   port.gs.tty=&tty;
+   sci_set_termios_cflag(&port);
+ }
+/*\PPC*/
  return 0;
 }

diff -ru linux_ORIG/drivers/char/sh-sci.h linux_PATCHED/drivers/char/sh-sci.h
--- linux_ORIG/drivers/char/sh-sci.h Mon May  1 10:55:33 2000
+++ linux_PATCHED/drivers/char/sh-sci.h Tue Apr 25 14:18:29 2000
@@ -9,6 +9,9 @@
  */
 #include <linux/config.h>

+/*PPC*/ #define SCI_DEFAULT_SPEED B9600
+/*PPC*/ #define SCI_DEFAULT_SPEED_VAL 9600
+
 #if defined(CONFIG_SH_SCI_SERIAL)
 #if defined(__sh3__)
 #define SCSMR  (volatile unsigned char *)0xfffffe80
@@ -28,7 +31,8 @@
 #define SCSPTR 0xffe0001c
 #endif

-#define SCSCR_INIT 0x30 /* TIE=0,RIE=0,TE=1,RE=1 */
+/*PPC #define SCSCR_INIT 0x30 *//* TIE=0,RIE=0,TE=1,RE=1 */
+/*PPC*/ #define SCSCR_INIT 0x31 /* TIE=0,RIE=0,TE=1,RE=1,CKE1=0,CKE0=1*/

 #define SCI_TD_E  0x80
 #define SCI_RD_F  0x40
@@ -187,7 +191,7 @@
  * -- Greg Banks 27Feb2000
  */

-#if defined(__sh3__)
+/*PPC #if defined(__sh3__)
 #define PCLK           14745600
 #elif defined(__SH4__)
 #define PCLK           33333333
@@ -199,4 +203,33 @@
 #define BPS_9600       SCBRR_VALUE(9600)
 #define BPS_19200      SCBRR_VALUE(19200)
 #define BPS_38400      SCBRR_VALUE(38400)
-#define BPS_115200     SCBRR_VALUE(115200)
+#define BPS_115200     SCBRR_VALUE(115200)*/
+
+/* PPC : This table is made from the Hitachi 7707 hardware manual.
+   It assumes
+   a bus clock of 30Mhz. It also specifies the clock source so that we can use
+   a greater range of baudrates */
+#define BPS_110        132
+#define CKS_BPS_110    3
+#define BPS_150        97
+#define CKS_BPS_150    2
+#define BPS_300        194
+#define CKS_BPS_300    2
+#define BPS_600        97
+#define CKS_BPS_600    2
+#define BPS_1200       194
+#define CKS_BPS_1200   1
+#define BPS_2400       97
+#define CKS_BPS_2400   1
+#define BPS_4800       194
+#define CKS_BPS_4800   0
+#define BPS_9600       97
+#define CKS_BPS_9600   0
+#define BPS_19200      48
+#define CKS_BPS_19200  0
+#define BPS_38400      23
+#define CKS_BPS_38400  0
+#define BPS_57600      15
+#define CKS_BPS_57600  0
+#define BPS_115200     7
+#define CKS_BPS_115200 0
--8<--8<--SNIP-SNIP--8<--8<--

Ideally, I think it'd be good to have an option in the .config to set the bus clock
speed and have several tables defined and selected with #ifdefs.

I don't know if any of the above will help anyone but I thought I might share my
findings.

Now for the plea for help :-) :

I assume everybody on the list has userland programs compiled dynamically and running
good on their boards. For some reason, I can run programs that have been compiled
statically against glibc just fine, but I can't run dynamically linked programs
because ld.so segfaults (I use Kaz' latest patch for glibc). What happens is that
ld.so starts, and eventually the function elf_machine_rela() (in
sysdeps/sh/sh3/dl-machine.h) is called during the initial relocation from _dl_start()
and the segfault occurs when the code tries (I think) to poke a fixed-up address in
the code section (which is read-only) instead of the GOT (which is read-write).

I believe it's a linker problem, but I'm no expert with ld.so nor ld so I'm having
hard times figuring out what's wrong. Anybody out there has a clue what the problem
might be ? I have traces of ld.so's startup and other informations relevant to the
problem if you think it'd be helpful.

Thanks in advance.
Take care

[BTW, you guys are doing a tremendous job with the LinuxSH project ! well done !]

---
Pierre-Philippe Coupard <pi...@li...>
Software Engineer, Lineo, Inc.
801-426-5001 x 208
---