Re: [patch] x86 BIOS interface for RTC on SGI UV

From: Russ Anderson
Date: Wed Jul 09 2008 - 18:09:57 EST

On Wed, Jul 09, 2008 at 11:47:57PM +0200, Rene Herman wrote:
> On 09-07-08 23:36, Russ Anderson wrote:
>
> >>... and wouldn't uv_bios_strerror/uv_bios_freq_base be better names?
> >
> >The plan is for both x86 and ia64 versions of uv, with this being
> >the x86 version. The ia64 version has ia64_sal_strerror()
> >and ia64_sal_freq_base(). Hence the x86_bios_* naming convention.
> >I'm not strongly tied to that convention, it just seemed logical.
>
> Ah, I see. Not much of an opinion then. x86_bios sounds a bit generic,
> but whatever...

On ia64, the sal interface is an Intel standard.
On x86, the bios interface is SGI UV specific.

I'll make it uv_bios_* .

> >Here is the updated patch.
>
> [ ... ]
>
> >+enum {
> >+ BIOS_STATUS_SUCCESS = 0,
> >+ BIOS_STATUS_UNIMPLEMENTED = -1,
> >+ BIOS_STATUS_EINVAL = -2,
> >+ BIOS_STATUS_ERROR = -3
> >+};
>
> [ .. ]
>
> >+extern long
> >+x86_bios_freq_base(unsigned long which, unsigned long *ticks_per_second,
> >+ unsigned long *drift_info);
>
> >+static __init void uv_rtc_init(void)
> >+{
> >+ unsigned long status, ticks_per_sec, drift;
>
> *status* should remain a long :-)

Ouch. Thanks.

---------------------------------------------------------------------
[patch] x86 BIOS interface for RTC on SGI UV

Real-time code needs to know the number of cycles per second
on SGI UV. The information is provided via a run time BIOS
call. This patch provides the linux side of that interface.
This is the first of several run time BIOS calls to be defined
in uv/bios.h and bios_uv.c.

Note that BIOS_CALL() is just a stub for now. The bios
side is being worked on.

Signed-off-by: Russ Anderson <rja@xxxxxxx>

---
arch/x86/kernel/Makefile | 1
arch/x86/kernel/bios_uv.c | 48 +++++++++++++++++++++++++++
arch/x86/kernel/genx2apic_uv_x.c | 24 +++++++++++++
include/asm-x86/uv/bios.h | 68 +++++++++++++++++++++++++++++++++++++++
4 files changed, 141 insertions(+)

Index: linux/include/asm-x86/uv/bios.h
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux/include/asm-x86/uv/bios.h 2008-07-09 17:01:42.000000000 -0500
@@ -0,0 +1,68 @@
+#ifndef _ASM_X86_BIOS_H
+#define _ASM_X86_BIOS_H
+
+/*
+ * BIOS layer definitions.
+ *
+ * Copyright (c) 2008 Silicon Graphics, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <linux/rtc.h>
+
+#define BIOS_FREQ_BASE 0x01000001
+
+enum {
+ BIOS_FREQ_BASE_PLATFORM = 0,
+ BIOS_FREQ_BASE_INTERVAL_TIMER = 1,
+ BIOS_FREQ_BASE_REALTIME_CLOCK = 2
+};
+
+# define BIOS_CALL(result, a0, a1, a2, a3, a4, a5, a6, a7) \
+ do { \
+ /* XXX - the real call goes here */ \
+ result.status = BIOS_STATUS_UNIMPLEMENTED; \
+ result.v0 = 0; \
+ result.v1 = 0; \
+ } while (0)
+
+enum {
+ BIOS_STATUS_SUCCESS = 0,
+ BIOS_STATUS_UNIMPLEMENTED = -1,
+ BIOS_STATUS_EINVAL = -2,
+ BIOS_STATUS_ERROR = -3
+};
+
+struct uv_bios_retval {
+ /*
+ * A zero status value indicates call completed without error.
+ * A negative status value indicates reason of call failure.
+ * A positive status value indicates success but an
+ * informational value should be printed (e.g., "reboot for
+ * change to take effect").
+ */
+ s64 status;
+ u64 v0;
+ u64 v1;
+ u64 v2;
+};
+
+extern long
+uv_bios_freq_base(unsigned long which, unsigned long *ticks_per_second,
+ unsigned long *drift_info);
+extern const char *uv_bios_strerror(long status);
+
+#endif /* _ASM_X86_BIOS_H */
Index: linux/arch/x86/kernel/genx2apic_uv_x.c
===================================================================
--- linux.orig/arch/x86/kernel/genx2apic_uv_x.c 2008-07-09 17:01:25.000000000 -0500
+++ linux/arch/x86/kernel/genx2apic_uv_x.c 2008-07-09 17:01:42.000000000 -0500
@@ -22,6 +22,7 @@
#include <asm/genapic.h>
#include <asm/uv/uv_mmrs.h>
#include <asm/uv/uv_hub.h>
+#include <asm/uv/bios.h>

DEFINE_PER_CPU(struct uv_hub_info_s, __uv_hub_info);
EXPORT_PER_CPU_SYMBOL_GPL(__uv_hub_info);
@@ -38,6 +39,9 @@ EXPORT_SYMBOL_GPL(uv_cpu_to_blade);
short uv_possible_blades;
EXPORT_SYMBOL_GPL(uv_possible_blades);

+unsigned long sn_rtc_cycles_per_second;
+EXPORT_SYMBOL(sn_rtc_cycles_per_second);
+
/* Start with all IRQs pointing to boot CPU. IRQ balancing will shift them. */

static cpumask_t uv_target_cpus(void)
@@ -208,6 +212,24 @@ static __init void get_lowmem_redirect(u
BUG();
}

+static __init void uv_rtc_init(void)
+{
+ unsigned long ticks_per_sec, drift;
+ long status;
+
+ status =
+ uv_bios_freq_base(BIOS_FREQ_BASE_REALTIME_CLOCK, &ticks_per_sec,
+ &drift);
+ if (status != 0 || ticks_per_sec < 100000) {
+ printk(KERN_WARNING
+ "unable to determine platform RTC clock frequency, "
+ "guessing.\n");
+ /* BIOS gives wrong value for clock freq. so guess */
+ sn_rtc_cycles_per_second = 1000000000000UL / 30000UL;
+ } else
+ sn_rtc_cycles_per_second = ticks_per_sec;
+}
+
static __init void uv_system_init(void)
{
union uvh_si_addr_map_config_u m_n_config;
@@ -258,6 +280,8 @@ static __init void uv_system_init(void)
node_id.v = uv_read_local_mmr(UVH_NODE_ID);
gnode_upper = (((unsigned long)node_id.s.node_id) &
~((1 << n_val) - 1)) << m_val;
+
+ uv_rtc_init();

for_each_present_cpu(cpu) {
nid = cpu_to_node(cpu);
Index: linux/arch/x86/kernel/bios_uv.c
===================================================================
--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++ linux/arch/x86/kernel/bios_uv.c 2008-07-09 17:01:42.000000000 -0500
@@ -0,0 +1,48 @@
+/*
+ * BIOS run time interface routines.
+ *
+ * Copyright (c) 2008 Silicon Graphics, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#include <asm/uv/bios.h>
+
+const char *
+uv_bios_strerror(long status)
+{
+ const char *str;
+ switch (status) {
+ case 0: str = "Call completed without error"; break;
+ case -1: str = "Not implemented"; break;
+ case -2: str = "Invalid argument"; break;
+ case -3: str = "Call completed with error"; break;
+ default: str = "Unknown BIOS status code"; break;
+ }
+ return str;
+}
+
+long
+uv_bios_freq_base(unsigned long which, unsigned long *ticks_per_second,
+ unsigned long *drift_info)
+{
+ struct uv_bios_retval isrv;
+
+ BIOS_CALL(isrv, BIOS_FREQ_BASE, which, 0, 0, 0, 0, 0, 0);
+ *ticks_per_second = isrv.v0;
+ *drift_info = isrv.v1;
+ return isrv.status;
+}
+EXPORT_SYMBOL_GPL(uv_bios_freq_base);
Index: linux/arch/x86/kernel/Makefile
===================================================================
--- linux.orig/arch/x86/kernel/Makefile 2008-07-09 17:01:25.000000000 -0500
+++ linux/arch/x86/kernel/Makefile 2008-07-09 17:01:43.000000000 -0500
@@ -103,6 +103,7 @@ obj-$(CONFIG_OLPC) += olpc.o
# 64 bit specific files
ifeq ($(CONFIG_X86_64),y)
obj-y += genapic_64.o genapic_flat_64.o genx2apic_uv_x.o tlb_uv.o
+ obj-y += bios_uv.o
obj-$(CONFIG_X86_PM_TIMER) += pmtimer_64.o
obj-$(CONFIG_AUDIT) += audit_64.o


--
Russ Anderson, OS RAS/Partitioning Project Lead
SGI - Silicon Graphics Inc rja@xxxxxxx
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