Mailing List Archive: [PATCH v3 7/8] xen/arm: introduce vexpress

[PATCH v3 7/8] xen/arm: introduce vexpress_syscfg

Dec 18, 2012, 10:46 AM

Post #1 of 3 (123 views)

Introduce a Versatile Express specific function to read/write
motherboard settings.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
---
xen/arch/arm/Makefile | 1 +
xen/arch/arm/platform_vexpress.c | 97 +++++++++++++++++++++++++++++++
xen/include/asm-arm/platform_vexpress.h | 23 +++++++
3 files changed, 121 insertions(+), 0 deletions(-)
create mode 100644 xen/arch/arm/platform_vexpress.c

diff --git a/xen/arch/arm/Makefile b/xen/arch/arm/Makefile
index 4c61b04..24689c5 100644
--- a/xen/arch/arm/Makefile
+++ b/xen/arch/arm/Makefile
@@ -18,6 +18,7 @@ obj-y += p2m.o
obj-y += percpu.o
obj-y += guestcopy.o
obj-y += physdev.o
+obj-y += platform_vexpress.o
obj-y += setup.o
obj-y += time.o
obj-y += smpboot.o
diff --git a/xen/arch/arm/platform_vexpress.c b/xen/arch/arm/platform_vexpress.c
new file mode 100644
index 0000000..41e3806
--- /dev/null
+++ b/xen/arch/arm/platform_vexpress.c
@@ -0,0 +1,97 @@
+/*
+ * xen/arch/arm/platform_vexpress.c
+ *
+ * Versatile Express specific settings
+ *
+ * Stefano Stabellini <stefano.stabellini@eu.citrix.com>
+ * Copyright (c) 2012 Citrix Systems.
+ *
+ * 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.
+ */
+
+#include <asm/platform_vexpress.h>
+#include <xen/mm.h>
+
+#define DCC_SHIFT 26
+#define FUNCTION_SHIFT 20
+#define SITE_SHIFT 16
+#define POSITION_SHIFT 12
+#define DEVICE_SHIFT 0
+
+int vexpress_syscfg(int write, int function, int device, uint32_t *data)
+{
+ uint32_t *syscfg = (uint32_t *) FIXMAP_ADDR(FIXMAP_MISC);
+ uint32_t stat;
+ int dcc = 0; /* DCC to access */
+ int site = 0; /* motherboard */
+ int position = 0; /* motherboard */
+
+ set_fixmap(FIXMAP_MISC, V2M_SYS_MMIO_BASE >> PAGE_SHIFT, DEV_SHARED);
+
+ if ( syscfg[V2M_SYS_CFGCTRL] & V2M_SYS_CFG_START )
+ return -1;
+
+ /* clear the complete bit in the V2M_SYS_CFGSTAT status register */
+ syscfg[V2M_SYS_CFGSTAT] = 0;
+
+ if ( write )
+ {
+ /* write data */
+ syscfg[V2M_SYS_CFGDATA] = *data;
+
+ /* set control register */
+ syscfg[V2M_SYS_CFGCTRL] = V2M_SYS_CFG_START | V2M_SYS_CFG_WRITE |
+ (dcc << DCC_SHIFT) | (function << FUNCTION_SHIFT) |
+ (site << SITE_SHIFT) | (position << POSITION_SHIFT) |
+ (device << DEVICE_SHIFT);
+
+ /* wait for complete flag to be set */
+ do {
+ stat = syscfg[V2M_SYS_CFGSTAT];
+ dsb();
+ } while ( !(stat & V2M_SYS_CFG_COMPLETE) );
+
+ /* check error status and return error flag if set */
+ if ( stat & V2M_SYS_CFG_ERROR )
+ return -1;
+ } else {
+ /* set control register */
+ syscfg[V2M_SYS_CFGCTRL] = V2M_SYS_CFG_START | (dcc << DCC_SHIFT) |
+ (function << FUNCTION_SHIFT) | (site << SITE_SHIFT) |
+ (position << POSITION_SHIFT) | (device << DEVICE_SHIFT);
+
+ /* wait for complete flag to be set */
+ do {
+ stat = syscfg[V2M_SYS_CFGSTAT];
+ dsb();
+ } while ( !(stat & V2M_SYS_CFG_COMPLETE) );
+
+ /* check error status flag and return error flag if set */
+ if ( stat & V2M_SYS_CFG_ERROR )
+ return -1;
+ else
+ /* read data */
+ *data = syscfg[V2M_SYS_CFGDATA];
+ }
+
+ clear_fixmap(FIXMAP_MISC);
+
+ return 0;
+}
+
+/*
+ * Local variables:
+ * mode: C
+ * c-set-style: "BSD"
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ */
diff --git a/xen/include/asm-arm/platform_vexpress.h b/xen/include/asm-arm/platform_vexpress.h
index 3556af3..407602d 100644
--- a/xen/include/asm-arm/platform_vexpress.h
+++ b/xen/include/asm-arm/platform_vexpress.h
@@ -6,6 +6,29 @@
#define V2M_SYS_FLAGSSET (0x30)
#define V2M_SYS_FLAGSCLR (0x34)

+#define V2M_SYS_CFGDATA (0x00A0/4)
+#define V2M_SYS_CFGCTRL (0x00A4/4)
+#define V2M_SYS_CFGSTAT (0x00A8/4)
+
+#define V2M_SYS_CFG_START (1<<31)
+#define V2M_SYS_CFG_WRITE (1<<30)
+#define V2M_SYS_CFG_ERROR (1<<1)
+#define V2M_SYS_CFG_COMPLETE (1<<0)
+
+#define V2M_SYS_CFG_OSC_FUNC 1
+#define V2M_SYS_CFG_OSC0 0
+#define V2M_SYS_CFG_OSC1 1
+#define V2M_SYS_CFG_OSC2 2
+#define V2M_SYS_CFG_OSC3 3
+#define V2M_SYS_CFG_OSC4 4
+#define V2M_SYS_CFG_OSC5 5
+
+#ifndef __ASSEMBLY__
+#include <xen/inttypes.h>
+
+int vexpress_syscfg(int write, int function, int device, uint32_t *data);
+#endif
+
#endif /* __ASM_ARM_PLATFORM_H */
/*
* Local variables:
--
1.7.2.5

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Re: [PATCH v3 7/8] xen/arm: introduce vexpress_syscfg [ In reply to ]

Ian.Campbell at citrix

Dec 19, 2012, 4:47 AM

Post #2 of 3 (113 views)

Permalink

On Tue, 2012-12-18 at 18:46 +0000, Stefano Stabellini wrote:
> Introduce a Versatile Express specific function to read/write
> motherboard settings.
>
> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> ---
> xen/arch/arm/Makefile | 1 +
> xen/arch/arm/platform_vexpress.c | 97 +++++++++++++++++++++++++++++++
> xen/include/asm-arm/platform_vexpress.h | 23 +++++++

I wonder if we ought to start a "platforms" subdirs include and arch?
This is presumably the first of many. Going the plat-<foo> route seems
unnecessary at least at this stage.

> +#include <asm/platform_vexpress.h>
> +#include <xen/mm.h>
> +
> +#define DCC_SHIFT 26
> +#define FUNCTION_SHIFT 20
> +#define SITE_SHIFT 16
> +#define POSITION_SHIFT 12
> +#define DEVICE_SHIFT 0
> +
> +int vexpress_syscfg(int write, int function, int device, uint32_t *data)
> +{
> + uint32_t *syscfg = (uint32_t *) FIXMAP_ADDR(FIXMAP_MISC);
> + uint32_t stat;
> + int dcc = 0; /* DCC to access */
> + int site = 0; /* motherboard */
> + int position = 0; /* motherboard */

motherboard twice?

> + set_fixmap(FIXMAP_MISC, V2M_SYS_MMIO_BASE >> PAGE_SHIFT, DEV_SHARED);
> +
> + if ( syscfg[V2M_SYS_CFGCTRL] & V2M_SYS_CFG_START )
> + return -1;
> +
> + /* clear the complete bit in the V2M_SYS_CFGSTAT status register */

Do you mean clear all the bits or specifically the "completion" bit?

> + syscfg[V2M_SYS_CFGSTAT] = 0;
> +
> + if ( write )
> + {
> + /* write data */
> + syscfg[V2M_SYS_CFGDATA] = *data;
> +
> + /* set control register */
> + syscfg[V2M_SYS_CFGCTRL] = V2M_SYS_CFG_START | V2M_SYS_CFG_WRITE |
> + (dcc << DCC_SHIFT) | (function << FUNCTION_SHIFT) |
> + (site << SITE_SHIFT) | (position << POSITION_SHIFT) |
> + (device << DEVICE_SHIFT);

Most of this shifting is repeated below, perhaps do it once into a local
var to avoid them getting out of sync?

> +
> + /* wait for complete flag to be set */
> + do {
> + stat = syscfg[V2M_SYS_CFGSTAT];
> + dsb();
> + } while ( !(stat & V2M_SYS_CFG_COMPLETE) );

I assume there's no wait-for-event or way to relax this spin loop?

Since this is repeated below a helper "wait_for_ocmplet" might be good.

Actually, this while bit "set control register" until the error check is
common to both the read and write cases, isn't it?

> +
> + /* check error status and return error flag if set */
> + if ( stat & V2M_SYS_CFG_ERROR )
> + return -1;
> + } else {
> + /* set control register */
> + syscfg[V2M_SYS_CFGCTRL] = V2M_SYS_CFG_START | (dcc << DCC_SHIFT) |
> + (function << FUNCTION_SHIFT) | (site << SITE_SHIFT) |
> + (position << POSITION_SHIFT) | (device << DEVICE_SHIFT);
> +
> + /* wait for complete flag to be set */
> + do {
> + stat = syscfg[V2M_SYS_CFGSTAT];
> + dsb();
> + } while ( !(stat & V2M_SYS_CFG_COMPLETE) );
> +
> + /* check error status flag and return error flag if set */
> + if ( stat & V2M_SYS_CFG_ERROR )
> + return -1;
> + else
> + /* read data */
> + *data = syscfg[V2M_SYS_CFGDATA];
> + }
> +
> + clear_fixmap(FIXMAP_MISC);
> +
> + return 0;
> +}
> +
> +/*
> + * Local variables:
> + * mode: C
> + * c-set-style: "BSD"
> + * c-basic-offset: 4
> + * indent-tabs-mode: nil
> + * End:
> + */
> diff --git a/xen/include/asm-arm/platform_vexpress.h b/xen/include/asm-arm/platform_vexpress.h
> index 3556af3..407602d 100644
> --- a/xen/include/asm-arm/platform_vexpress.h
> +++ b/xen/include/asm-arm/platform_vexpress.h
> @@ -6,6 +6,29 @@
> #define V2M_SYS_FLAGSSET (0x30)
> #define V2M_SYS_FLAGSCLR (0x34)
>
> +#define V2M_SYS_CFGDATA (0x00A0/4)
> +#define V2M_SYS_CFGCTRL (0x00A4/4)
> +#define V2M_SYS_CFGSTAT (0x00A8/4)

It'd be better to either define all registers in bytes (as the existing
FLAGS*) or words (the new ones) and not to mix the two...

> +
> +#define V2M_SYS_CFG_START (1<<31)
> +#define V2M_SYS_CFG_WRITE (1<<30)
> +#define V2M_SYS_CFG_ERROR (1<<1)
> +#define V2M_SYS_CFG_COMPLETE (1<<0)
> +
> +#define V2M_SYS_CFG_OSC_FUNC 1
> +#define V2M_SYS_CFG_OSC0 0
> +#define V2M_SYS_CFG_OSC1 1
> +#define V2M_SYS_CFG_OSC2 2
> +#define V2M_SYS_CFG_OSC3 3
> +#define V2M_SYS_CFG_OSC4 4
> +#define V2M_SYS_CFG_OSC5 5
> +
> +#ifndef __ASSEMBLY__
> +#include <xen/inttypes.h>
> +
> +int vexpress_syscfg(int write, int function, int device, uint32_t *data);
> +#endif
> +
> #endif /* __ASM_ARM_PLATFORM_H */
> /*
> * Local variables:

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Re: [PATCH v3 7/8] xen/arm: introduce vexpress_syscfg [ In reply to ]

stefano.stabellini at eu

Jan 8, 2013, 9:16 AM

Post #3 of 3 (116 views)

Permalink

On Wed, 19 Dec 2012, Ian Campbell wrote:
> On Tue, 2012-12-18 at 18:46 +0000, Stefano Stabellini wrote:
> > Introduce a Versatile Express specific function to read/write
> > motherboard settings.
> >
> > Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
> > ---
> > xen/arch/arm/Makefile | 1 +
> > xen/arch/arm/platform_vexpress.c | 97 +++++++++++++++++++++++++++++++
> > xen/include/asm-arm/platform_vexpress.h | 23 +++++++
>
> I wonder if we ought to start a "platforms" subdirs include and arch?
> This is presumably the first of many. Going the plat-<foo> route seems
> unnecessary at least at this stage.

I can move these two files in a subdirectory, but until we have at
least another platform is going to be difficult to come up with a decent
abstraction.

> > +#include <asm/platform_vexpress.h>
> > +#include <xen/mm.h>
> > +
> > +#define DCC_SHIFT 26
> > +#define FUNCTION_SHIFT 20
> > +#define SITE_SHIFT 16
> > +#define POSITION_SHIFT 12
> > +#define DEVICE_SHIFT 0
> > +
> > +int vexpress_syscfg(int write, int function, int device, uint32_t *data)
> > +{
> > + uint32_t *syscfg = (uint32_t *) FIXMAP_ADDR(FIXMAP_MISC);
> > + uint32_t stat;
> > + int dcc = 0; /* DCC to access */
> > + int site = 0; /* motherboard */
> > + int position = 0; /* motherboard */
>
> motherboard twice?
>
> > + set_fixmap(FIXMAP_MISC, V2M_SYS_MMIO_BASE >> PAGE_SHIFT, DEV_SHARED);
> > +
> > + if ( syscfg[V2M_SYS_CFGCTRL] & V2M_SYS_CFG_START )
> > + return -1;
> > +
> > + /* clear the complete bit in the V2M_SYS_CFGSTAT status register */
>
> Do you mean clear all the bits or specifically the "completion" bit?

the completion bit but there isn't much else on that register, so I
think it is OK to zero it.

> > + syscfg[V2M_SYS_CFGSTAT] = 0;
> > +
> > + if ( write )
> > + {
> > + /* write data */
> > + syscfg[V2M_SYS_CFGDATA] = *data;
> > +
> > + /* set control register */
> > + syscfg[V2M_SYS_CFGCTRL] = V2M_SYS_CFG_START | V2M_SYS_CFG_WRITE |
> > + (dcc << DCC_SHIFT) | (function << FUNCTION_SHIFT) |
> > + (site << SITE_SHIFT) | (position << POSITION_SHIFT) |
> > + (device << DEVICE_SHIFT);
>
> Most of this shifting is repeated below, perhaps do it once into a local
> var to avoid them getting out of sync?
>
> > +
> > + /* wait for complete flag to be set */
> > + do {
> > + stat = syscfg[V2M_SYS_CFGSTAT];
> > + dsb();
> > + } while ( !(stat & V2M_SYS_CFG_COMPLETE) );
>
> I assume there's no wait-for-event or way to relax this spin loop?

Nope

> Since this is repeated below a helper "wait_for_ocmplet" might be good.
>
> Actually, this while bit "set control register" until the error check is
> common to both the read and write cases, isn't it?

I'll refactor them both into a separate function

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