[PATCH 16/19] bootwrapper: Add xlate_reg(), and use it to find serial registers.

[PATCH 16/19] bootwrapper: Add xlate_reg(), and use it to find serial registers.

[Scott Wood]

xlate_reg() uses the ranges properties of a node's parentage to find the
absolute physical address of the node's registers.

The ns16550 driver uses this when no virtual-reg property is found.

Signed-off-by: Scott Wood <scottwood@freescale.com>
---
 arch/powerpc/boot/Makefile  |    2 +-
 arch/powerpc/boot/devtree.c |  207 +++++++++++++++++++++++++++++++++++++++++++
 arch/powerpc/boot/ns16550.c |    9 ++-
 arch/powerpc/boot/ops.h     |    1 +
 4 files changed, 216 insertions(+), 3 deletions(-)
 create mode 100644 arch/powerpc/boot/devtree.c

diff --git a/arch/powerpc/boot/Makefile b/arch/powerpc/boot/Makefile
index 3c1202c..d1a5a60 100644
--- a/arch/powerpc/boot/Makefile
+++ b/arch/powerpc/boot/Makefile
@@ -44,7 +44,7 @@ $(addprefix $(obj)/,$(zlib) main.o): $(addprefix $(obj)/,$(zliblinuxheader)) \
 
 src-wlib := string.S crt0.S stdio.c main.c flatdevtree.c flatdevtree_misc.c \
 		ns16550.c serial.c simple_alloc.c div64.S util.S \
-		gunzip_util.c $(zlib)
+		gunzip_util.c devtree.c $(zlib)
 src-plat := of.c
 src-boot := $(src-wlib) $(src-plat) empty.c
 
diff --git a/arch/powerpc/boot/devtree.c b/arch/powerpc/boot/devtree.c
new file mode 100644
index 0000000..9fee6fb
--- /dev/null
+++ b/arch/powerpc/boot/devtree.c
@@ -0,0 +1,207 @@
+/*
+ * Device Tree functions that are semantic, not structural
+ *
+ * Author: Scott Wood <scottwood@freescale.com>
+ *
+ * Copyright (c) 2007 Freescale Semiconductor, Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License version 2 as published
+ * by the Free Software Foundation.
+ */
+
+#include "ops.h"
+#include "string.h"
+
+#define MAX_ADDR_CELLS 4
+#define MAX_RANGES 8
+
+static int get_reg_format(void *node, u32 *naddr, u32 *nsize)
+{
+	int got_addr = 0, got_size = 0;
+
+	while (node && !(got_addr && got_size)) {
+		if (!got_addr && getprop(node, "#address-cells",
+		                         naddr, 4) == 4)
+			got_addr = 1;
+		if (!got_size && getprop(node, "#size-cells",
+		                         nsize, 4) == 4)
+			got_size = 1;
+
+		node = get_parent(node);
+	}
+
+	if (*naddr <= 0 || *naddr > MAX_ADDR_CELLS ||
+	    *nsize <= 0 || *nsize > *naddr)
+		return 0;
+
+	return got_addr && got_size;
+}
+
+static int sub_reg(u32 *reg, u32 *sub, u32 naddr)
+{
+	int i, borrow = 0;
+
+	for (i = 0; i < naddr; i++) {
+		int prev_borrow = borrow;
+		borrow = reg[i] < sub[i] + prev_borrow;
+		reg[i] -= sub[i] + prev_borrow;
+	}
+
+	return !borrow;
+}
+
+static int add_reg(u32 *reg, u32 *add, u32 naddr, u32 naddr_add)
+{
+	int i, carry = 0;
+	int diff = naddr - naddr_add;
+
+	if (diff < 0) {
+		for (i = 0; i < -diff; i++)
+			if (*add++ != 0)
+				return 0;
+
+		diff = 0;
+	}
+
+	for (i = diff; i < naddr; i++) {
+		u64 tmp = (u64)reg[i] + add[i - diff] + carry;
+		carry = tmp >> 32;
+		reg[i] = (u32)tmp;
+	}
+
+	return !carry;
+}
+
+/* It is assumed that if the first byte of reg fits in a
+ * range, then the whole reg block fits.  It is also assumed
+ * that #size-cells <= #address-cells.
+ */
+static int compare_reg(u32 *reg, u32 *range, u32 *rangesize,
+                       u32 naddr, u32 nsize)
+{
+	int i, sizeoff = naddr - nsize;
+
+	for (i = 0; i < naddr; i++) {
+		if (reg[i] < range[i])
+			return 0;
+		if (reg[i] > range[i])
+			break;
+	}
+
+	for (i = sizeoff; i < naddr; i++) {
+		u32 end = range[i] + rangesize[i - sizeoff];
+
+		if (reg[i] < end)
+			break;
+		if (reg[i] > end)
+			return 0;
+		if (i == naddr && reg[i] == end)
+			return 0;
+	}
+
+	return 1;
+}
+
+static int find_range(u32 *reg, u32 *ranges, int naddr,
+                      int nsize, int nparentaddr, int buflen)
+{
+	int nrange = naddr + nparentaddr + nsize;
+	int i;
+
+	for (i = 0; i + nrange <= buflen; i += nrange) {
+		if (compare_reg(reg, ranges + i,
+		                ranges + i + naddr + nparentaddr,
+		                naddr, nsize))
+			return i;
+	}
+
+	return -1;
+}
+
+/* Currently only generic buses without special encodings are supported.
+ * In particular, PCI is not supported.  Also, only the beginning of the
+ * reg block is tracked; size is ignored except in ranges.
+ */
+int xlate_reg(void *node, int res, unsigned long *addr,
+              unsigned long *size)
+{
+	u32 last_addr[MAX_ADDR_CELLS];
+	u32 buf[MAX_ADDR_CELLS * MAX_RANGES * 3];
+	void *parent;
+	u64 ret_addr, ret_size;
+	u32 naddr, nsize, prev_naddr, prev_nsize;
+	int buflen, offset;
+
+	parent = get_parent(node);
+	if (!parent)
+		return 0;
+
+	if (!get_reg_format(parent, &naddr, &nsize))
+		return 0;
+
+	if (nsize > 2)
+		return 0;
+
+	buflen = getprop(node, "reg", buf, sizeof(buf)) / 4;
+	offset = (naddr + nsize) * res;
+
+	if (buflen < offset + naddr + nsize)
+		return 0;
+
+	memcpy(last_addr, buf + offset, 4 * naddr);
+
+	ret_size = buf[offset + naddr];
+	if (nsize == 2) {
+		ret_size <<= 32;
+		ret_size |= buf[offset + naddr + 1];
+	}
+
+	while ((node = get_parent(node))) {
+		prev_naddr = naddr;
+		prev_nsize = nsize;
+
+		if (!get_reg_format(node, &naddr, &nsize))
+			return 0;
+
+		buflen = getprop(node, "ranges",
+		                        buf, sizeof(buf));
+		if (buflen < 0)
+			continue;
+		if (buflen > sizeof(buf))
+			return 0;
+
+		offset = find_range(last_addr, buf, prev_naddr,
+		                    prev_nsize, naddr, buflen / 4);
+
+		if (offset < 0)
+			return 0;
+
+		if (!sub_reg(last_addr, buf + offset, prev_naddr) ||
+		    !add_reg(buf + offset + prev_naddr, last_addr,
+		             naddr, prev_naddr))
+			return 0;
+
+		memcpy(last_addr, buf + offset + prev_naddr, 4 * naddr);
+	}
+
+	if (naddr > 2)
+		return 0;
+
+	ret_addr = last_addr[0];
+	if (naddr == 2) {
+		ret_addr <<= 32;
+		ret_addr |= last_addr[1];
+	}
+
+	if (sizeof(void *) == 4 &&
+	    (ret_addr >= 0x100000000ULL || ret_size > 0x100000000ULL ||
+	     ret_addr + ret_size > 0x100000000ULL))
+		return 0;
+
+	*addr = ret_addr;
+	if (size)
+		*size = ret_size;
+
+	return 1;
+}
diff --git a/arch/powerpc/boot/ns16550.c b/arch/powerpc/boot/ns16550.c
index 1ffe72e..cce7a11 100644
--- a/arch/powerpc/boot/ns16550.c
+++ b/arch/powerpc/boot/ns16550.c
@@ -55,10 +55,15 @@ static u8 ns16550_tstc(void)
 int ns16550_console_init(void *devp, struct serial_console_data *scdp)
 {
 	int n;
+	unsigned long reg_phys;
 
 	n = getprop(devp, "virtual-reg", &reg_base, sizeof(reg_base));
-	if (n != sizeof(reg_base))
-		return -1;
+	if (n != sizeof(reg_base)) {
+		if (!xlate_reg(devp, 0, &reg_phys, NULL))
+			return -1;
+
+		reg_base = (void *)reg_phys;
+	}
 
 	n = getprop(devp, "reg-shift", &reg_shift, sizeof(reg_shift));
 	if (n != sizeof(reg_shift))
diff --git a/arch/powerpc/boot/ops.h b/arch/powerpc/boot/ops.h
index 6b4fd9b..629eaf7 100644
--- a/arch/powerpc/boot/ops.h
+++ b/arch/powerpc/boot/ops.h
@@ -80,6 +80,7 @@ int serial_console_init(void);
 int ns16550_console_init(void *devp, struct serial_console_data *scdp);
 void *simple_alloc_init(char *base, u32 heap_size, u32 granularity,
 		u32 max_allocs);
+int xlate_reg(void *node, int res, unsigned long *addr, unsigned long *size);
 
 
 static inline void *finddevice(const char *name)
-- 
1.5.0.3

Re: [PATCH 16/19] bootwrapper: Add xlate_reg(), and use it to find serial registers.

[Mark A. Greer]

On Mon, Mar 12, 2007 at 02:42:02PM -0600, Scott Wood wrote:

> diff --git a/arch/powerpc/boot/ns16550.c b/arch/powerpc/boot/ns16550.c
> index 1ffe72e..cce7a11 100644
> --- a/arch/powerpc/boot/ns16550.c
> +++ b/arch/powerpc/boot/ns16550.c
> @@ -55,10 +55,15 @@ static u8 ns16550_tstc(void)
>  int ns16550_console_init(void *devp, struct serial_console_data *scdp)
>  {
>  	int n;
> +	unsigned long reg_phys;
>  
>  	n = getprop(devp, "virtual-reg", &reg_base, sizeof(reg_base));
> -	if (n != sizeof(reg_base))
> -		return -1;
> +	if (n != sizeof(reg_base)) {
> +		if (!xlate_reg(devp, 0, &reg_phys, NULL))
> +			return -1;
> +
> +		reg_base = (void *)reg_phys;
> +	}

NACK.

'virtual-reg' _is_ the fully translated virtual address.
Its simply the virtual address that maps to the fully translated
physical addr in the 'reg' property.

Even if it wasn't, 'ranges' only work for physical/'reg' properties
and can't be used for a virtual one--you'd have to make a parellel
'ranges' thingy for 'virtual-reg'.

Mark

Re: [PATCH 16/19] bootwrapper: Add xlate_reg(), and use it to find serial registers.

[David Gibson]

On Mon, Mar 12, 2007 at 04:01:48PM -0700, Mark A. Greer wrote:
> On Mon, Mar 12, 2007 at 02:42:02PM -0600, Scott Wood wrote:
> 
> > diff --git a/arch/powerpc/boot/ns16550.c b/arch/powerpc/boot/ns16550.c
> > index 1ffe72e..cce7a11 100644
> > --- a/arch/powerpc/boot/ns16550.c
> > +++ b/arch/powerpc/boot/ns16550.c
> > @@ -55,10 +55,15 @@ static u8 ns16550_tstc(void)
> >  int ns16550_console_init(void *devp, struct serial_console_data *scdp)
> >  {
> >  	int n;
> > +	unsigned long reg_phys;
> >  
> >  	n = getprop(devp, "virtual-reg", &reg_base, sizeof(reg_base));
> > -	if (n != sizeof(reg_base))
> > -		return -1;
> > +	if (n != sizeof(reg_base)) {
> > +		if (!xlate_reg(devp, 0, &reg_phys, NULL))
> > +			return -1;
> > +
> > +		reg_base = (void *)reg_phys;
> > +	}
> 
> NACK.
> 
> 'virtual-reg' _is_ the fully translated virtual address.
> Its simply the virtual address that maps to the fully translated
> physical addr in the 'reg' property.
> 
> Even if it wasn't, 'ranges' only work for physical/'reg' properties
> and can't be used for a virtual one--you'd have to make a parellel
> 'ranges' thingy for 'virtual-reg'.

I think you're misreading, Mark.  The patch only attempts to translate
the reg if the virtual-reg property is *not* valid.

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

Re: [PATCH 16/19] bootwrapper: Add xlate_reg(), and use it to find serial registers.

[Mark A. Greer]

On Tue, Mar 13, 2007 at 10:29:25AM +1100, David Gibson wrote:
> On Mon, Mar 12, 2007 at 04:01:48PM -0700, Mark A. Greer wrote:
> > On Mon, Mar 12, 2007 at 02:42:02PM -0600, Scott Wood wrote:
> > 
> > > diff --git a/arch/powerpc/boot/ns16550.c b/arch/powerpc/boot/ns16550.c
> > > index 1ffe72e..cce7a11 100644
> > > --- a/arch/powerpc/boot/ns16550.c
> > > +++ b/arch/powerpc/boot/ns16550.c
> > > @@ -55,10 +55,15 @@ static u8 ns16550_tstc(void)
> > >  int ns16550_console_init(void *devp, struct serial_console_data *scdp)
> > >  {
> > >  	int n;
> > > +	unsigned long reg_phys;
> > >  
> > >  	n = getprop(devp, "virtual-reg", &reg_base, sizeof(reg_base));
> > > -	if (n != sizeof(reg_base))
> > > -		return -1;
> > > +	if (n != sizeof(reg_base)) {
> > > +		if (!xlate_reg(devp, 0, &reg_phys, NULL))
> > > +			return -1;
> > > +
> > > +		reg_base = (void *)reg_phys;
> > > +	}
> > 
> > NACK.
> > 
> > 'virtual-reg' _is_ the fully translated virtual address.
> > Its simply the virtual address that maps to the fully translated
> > physical addr in the 'reg' property.
> > 
> > Even if it wasn't, 'ranges' only work for physical/'reg' properties
> > and can't be used for a virtual one--you'd have to make a parellel
> > 'ranges' thingy for 'virtual-reg'.
> 
> I think you're misreading, Mark.  The patch only attempts to translate
> the reg if the virtual-reg property is *not* valid.

Oops.  :)

Acked-by: Mark A. Greer <mgreer@mvista.com>