[PATCH] powerpc: New DCR access methods

[PATCH] powerpc: New DCR access methods

[Benjamin Herrenschmidt]

Ѕubject: powerpc: generic DCR access

This patch adds new dcr_map/dcr_read/dcr_write accessors for DCRs that
can be used by drivers to transparently address either native DCRs or
memory mapped DCRs. The implementation for memory mapped DCRs is done
after the binding being currently worked on for SLOF and the Axon
chipset. This patch enables it for the cell native platform

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
---

Arnd: This will replace powerpc-generic-dcr.diff, though don't put it in
your tree just yet. I'll have other axon related patches including a new
one porting emac over and a new infrastructure for probing OF devices
in the upcoming few days. I'm posting this one early to get comments from
4xx folks.

Eugene: As you can see, the overhead for 4xx is nil. I have a patch hacking
the MAL driver to use those instead of mfdcr/mtdcr. I did it to quicky test
I didn't do anything stupid and it still builds with an ebony_defconfig with
ARCH=ppc. I'll send it separately.

Index: linux-cell/include/asm-powerpc/dcr.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-cell/include/asm-powerpc/dcr.h	2006-10-11 15:28:41.000000000 +1000
@@ -0,0 +1,40 @@
+/*
+ * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ *
+ *   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
+ */
+
+#ifndef _ASM_POWERPC_DCR_H
+#define _ASM_POWERPC_DCR_H
+#ifdef __KERNEL__
+
+#ifdef CONFIG_PPC_DCR_NATIVE
+#include <asm/dcr-native.h>
+#else
+#include <asm/dcr-mmio.h>
+#endif
+
+/*
+ * On CONFIG_PPC_MERGE, we have additional helpers to read the DCR
+ * base from the device-tree
+ */
+#ifdef CONFIG_PPC_MERGE
+extern int dcr_resource_start(struct device_node *np, unsigned int index);
+extern int dcr_resource_len(struct device_node *np, unsigned int index);
+#endif /* CONFIG_PPC_MERGE */
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_POWERPC_DCR_H */
Index: linux-cell/arch/powerpc/Kconfig
===================================================================
--- linux-cell.orig/arch/powerpc/Kconfig	2006-10-11 15:27:03.000000000 +1000
+++ linux-cell/arch/powerpc/Kconfig	2006-10-11 15:29:31.000000000 +1000
@@ -160,9 +160,11 @@ config PPC_86xx
 
 config 40x
 	bool "AMCC 40x"
+	select PPC_DCR_NATIVE
 
 config 44x
 	bool "AMCC 44x"
+	select PPC_DCR_NATIVE
 
 config 8xx
 	bool "Freescale 8xx"
@@ -208,6 +210,19 @@ config PPC_FPU
 	bool
 	default y if PPC64
 
+config PPC_DCR_NATIVE
+	bool
+	default n
+
+config PPC_DCR_MMIO
+	bool
+	default n
+
+config PPC_DCR
+	bool
+	depends on PPC_DCR_NATIVE || PPC_DCR_MMIO
+	default y
+
 config BOOKE
 	bool
 	depends on E200 || E500
@@ -445,6 +460,7 @@ config PPC_CELL
 config PPC_CELL_NATIVE
 	bool
 	select PPC_CELL
+	select PPC_DCR_MMIO
 	default n
 
 config PPC_IBM_CELL_BLADE
Index: linux-cell/include/asm-powerpc/dcr-mmio.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-cell/include/asm-powerpc/dcr-mmio.h	2006-10-11 15:34:02.000000000 +1000
@@ -0,0 +1,51 @@
+/*
+ * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ *
+ *   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
+ */
+
+#ifndef _ASM_POWERPC_DCR_MMIO_H
+#define _ASM_POWERPC_DCR_MMIO_H
+#ifdef __KERNEL__
+
+#include <asm/io.h>
+
+typedef struct { void __iomem *token; unsigned int stride; } dcr_host_t;
+
+#define DCR_MAP_OK(host)	((host).token != NULL)
+
+extern dcr_host_t dcr_map(struct device_node *dev, unsigned int dcr_n,
+			  unsigned int dcr_c);
+extern void dcr_unmap(dcr_host_t host, unsigned int dcr_n, unsigned int dcr_c);
+
+static inline u32 dcr_read(dcr_host_t host, unsigned int dcr_n)
+{
+	return in_be32(host.token + dcr_n * host.stride);
+}
+
+static inline void dcr_write(dcr_host_t host, unsigned int dcr_n, u32 value)
+{
+	out_be32(host.token + dcr_n * host.stride, value);
+}
+
+extern u64 of_translate_dcr_address(struct device_node *dev,
+				    unsigned int dcr_n,
+				    unsigned int *stride);
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_POWERPC_DCR_MMIO_H */
+
+
Index: linux-cell/include/asm-powerpc/dcr-native.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-cell/include/asm-powerpc/dcr-native.h	2006-10-11 15:28:41.000000000 +1000
@@ -0,0 +1,39 @@
+/*
+ * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ *
+ *   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
+ */
+
+#ifndef _ASM_POWERPC_DCR_NATIVE_H
+#define _ASM_POWERPC_DCR_NATIVE_H
+#ifdef __KERNEL__
+
+#include <asm/reg.h>
+
+typedef struct {} dcr_host_t;
+
+#define DCR_MAP_OK(host)	(1)
+
+#define dcr_map(dev, dcr_n, dcr_c)	{}
+#define dcr_unmap(host, dcr_n, dcr_c)	{}
+#define dcr_read(host, dcr_n)		mfdcr(dcr_n)
+#define dcr_write(host, dcr_n, value)	mtdcr(dcr_n, value)
+
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_POWERPC_DCR_NATIVE_H */
+
+
Index: linux-cell/arch/ppc/Kconfig
===================================================================
--- linux-cell.orig/arch/ppc/Kconfig	2006-10-11 15:27:03.000000000 +1000
+++ linux-cell/arch/ppc/Kconfig	2006-10-11 15:28:41.000000000 +1000
@@ -77,9 +77,11 @@ config 6xx
 
 config 40x
 	bool "40x"
+	select PPC_DCR_NATIVE
 
 config 44x
 	bool "44x"
+	select PPC_DCR_NATIVE
 
 config 8xx
 	bool "8xx"
@@ -95,6 +97,15 @@ endchoice
 config PPC_FPU
 	bool
 
+config PPC_DCR_NATIVE
+	bool
+	default n
+
+config PPC_DCR
+	bool
+	depends on PPC_DCR_NATIVE
+	default y
+
 config BOOKE
 	bool
 	depends on E200 || E500
Index: linux-cell/arch/powerpc/kernel/Makefile
===================================================================
--- linux-cell.orig/arch/powerpc/kernel/Makefile	2006-10-11 15:27:03.000000000 +1000
+++ linux-cell/arch/powerpc/kernel/Makefile	2006-10-11 15:28:41.000000000 +1000
@@ -60,6 +60,8 @@ obj-$(CONFIG_BOOTX_TEXT)	+= btext.o
 obj-$(CONFIG_SMP)		+= smp.o
 obj-$(CONFIG_KPROBES)		+= kprobes.o
 obj-$(CONFIG_PPC_UDBG_16550)	+= legacy_serial.o udbg_16550.o
+obj-$(CONFIG_PPC_DCR)		+= dcr.o
+
 module-$(CONFIG_PPC64)		+= module_64.o
 obj-$(CONFIG_MODULES)		+= $(module-y)
 
Index: linux-cell/arch/powerpc/kernel/dcr.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-cell/arch/powerpc/kernel/dcr.c	2006-10-11 15:35:34.000000000 +1000
@@ -0,0 +1,120 @@
+/*
+ * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ *
+ *   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/prom.h>
+#include <asm/dcr.h>
+
+int dcr_resource_start(struct device_node *np, unsigned int index)
+{
+	unsigned int ds;
+	const u32 *dr = get_property(np, "dcr-reg", &ds);
+
+	if (dr == NULL || ds & 1 || index >= (ds / 8))
+		return -EINVAL;
+
+	return dr[index * 2];
+}
+
+int dcr_resource_len(struct device_node *np, unsigned int index)
+{
+	unsigned int ds;
+	const u32 *dr = get_property(np, "dcr-reg", &ds);
+
+	if (dr == NULL || ds & 1 || index >= (ds / 8))
+		return -EINVAL;
+
+	return dr[index * 2 + 1];
+}
+
+#ifndef CONFIG_PPC_DCR_NATIVE
+
+static struct device_node * find_dcr_parent(struct device_node * node)
+{
+	struct device_node *par, *tmp;
+	const u32 *p;
+
+	for (par = of_node_get(node); par;) {
+		if (get_property(par, "dcr-controller", NULL))
+		    break;
+		p = get_property(par, "dcr-parent", NULL);
+		tmp = par;
+		if (p == NULL)
+			par = of_get_parent(par);
+		else
+			par = of_find_node_by_phandle(*p);
+		of_node_put(tmp);
+	}
+	return par;
+}
+
+u64 of_translate_dcr_address(struct device_node *dev,
+			     unsigned int dcr_n,
+			     unsigned int *stride)
+{
+	struct device_node *dp;
+	const u32 *p;
+	u64 ret;
+
+	dp = find_dcr_parent(dev);
+	if (dp == NULL)
+		return OF_BAD_ADDR;
+
+	/* Stride is not properly defined yet, default to 0x10 for Axon */
+	p = get_property(dp, "dcr-mmio-stride", NULL);
+	*stride = (p == NULL) ? 0x10 : *p;
+
+	p = get_property(dp, "dcr-mmio-range", NULL);
+	if (p == NULL)
+		return OF_BAD_ADDR;
+
+	/* Maybe could do some better range checking here */
+	ret = of_translate_address(dp, p);
+	if (ret != OF_BAD_ADDR)
+		ret += *stride * dcr_n;
+	return ret;
+}
+
+dcr_host_t dcr_map(struct device_node *dev, unsigned int dcr_n,
+		   unsigned int dcr_c)
+{
+	dcr_host_t ret = { .token = NULL, .stride = 0 };
+	u64 addr;
+
+	addr = of_translate_dcr_address(dev, dcr_n, &ret.stride);
+	if (addr == OF_BAD_ADDR)
+		return ret;
+	ret.token = ioremap(addr, dcr_c * ret.stride);
+	if (ret.token == NULL)
+		return ret;
+	ret.token -= dcr_n * ret.stride;
+	return ret;
+}
+
+void dcr_unmap(dcr_host_t host, unsigned int dcr_n, unsigned int dcr_c)
+{
+	dcr_host_t h = host;
+
+	if (h.token == NULL)
+		return;
+	h.token -= dcr_n * h.stride;
+	iounmap(h.token);
+	h.token = NULL;
+}
+
+#endif /* !defined(CONFIG_PPC_DCR_NATIVE) */

[PATCH] powerpc: New DCR access methods

[Benjamin Herrenschmidt]

This patch adds new dcr_map/dcr_read/dcr_write accessors for DCRs that
can be used by drivers to transparently address either native DCRs or
memory mapped DCRs. The implementation for memory mapped DCRs is done
after the binding being currently worked on for SLOF and the Axon
chipset. This patch enables it for the cell native platform

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Index: linux-cell/include/asm-powerpc/dcr.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-cell/include/asm-powerpc/dcr.h	2006-10-16 16:42:32.000000000 +1000
@@ -0,0 +1,42 @@
+/*
+ * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ *
+ *   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
+ */
+
+#ifndef _ASM_POWERPC_DCR_H
+#define _ASM_POWERPC_DCR_H
+#ifdef __KERNEL__
+
+#ifdef CONFIG_PPC_DCR_NATIVE
+#include <asm/dcr-native.h>
+#else
+#include <asm/dcr-mmio.h>
+#endif
+
+/*
+ * On CONFIG_PPC_MERGE, we have additional helpers to read the DCR
+ * base from the device-tree
+ */
+#ifdef CONFIG_PPC_MERGE
+extern unsigned int dcr_resource_start(struct device_node *np,
+				       unsigned int index);
+extern unsigned int dcr_resource_len(struct device_node *np,
+				     unsigned int index);
+#endif /* CONFIG_PPC_MERGE */
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_POWERPC_DCR_H */
Index: linux-cell/arch/powerpc/Kconfig
===================================================================
--- linux-cell.orig/arch/powerpc/Kconfig	2006-10-16 15:05:04.000000000 +1000
+++ linux-cell/arch/powerpc/Kconfig	2006-10-16 17:20:38.000000000 +1000
@@ -160,9 +160,11 @@ config PPC_86xx
 
 config 40x
 	bool "AMCC 40x"
+	select PPC_DCR_NATIVE
 
 config 44x
 	bool "AMCC 44x"
+	select PPC_DCR_NATIVE
 
 config 8xx
 	bool "Freescale 8xx"
@@ -208,6 +210,19 @@ config PPC_FPU
 	bool
 	default y if PPC64
 
+config PPC_DCR_NATIVE
+	bool
+	default n
+
+config PPC_DCR_MMIO
+	bool
+	default n
+
+config PPC_DCR
+	bool
+	depends on PPC_DCR_NATIVE || PPC_DCR_MMIO
+	default y
+
 config BOOKE
 	bool
 	depends on E200 || E500
@@ -445,6 +460,7 @@ config PPC_CELL
 config PPC_CELL_NATIVE
 	bool
 	select PPC_CELL
+	select PPC_DCR_MMIO
 	default n
 
 config PPC_IBM_CELL_BLADE
Index: linux-cell/include/asm-powerpc/dcr-mmio.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-cell/include/asm-powerpc/dcr-mmio.h	2006-10-16 17:20:37.000000000 +1000
@@ -0,0 +1,51 @@
+/*
+ * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ *
+ *   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
+ */
+
+#ifndef _ASM_POWERPC_DCR_MMIO_H
+#define _ASM_POWERPC_DCR_MMIO_H
+#ifdef __KERNEL__
+
+#include <asm/io.h>
+
+typedef struct { void __iomem *token; unsigned int stride; } dcr_host_t;
+
+#define DCR_MAP_OK(host)	((host).token != NULL)
+
+extern dcr_host_t dcr_map(struct device_node *dev, unsigned int dcr_n,
+			  unsigned int dcr_c);
+extern void dcr_unmap(dcr_host_t host, unsigned int dcr_n, unsigned int dcr_c);
+
+static inline u32 dcr_read(dcr_host_t host, unsigned int dcr_n)
+{
+	return in_be32(host.token + dcr_n * host.stride);
+}
+
+static inline void dcr_write(dcr_host_t host, unsigned int dcr_n, u32 value)
+{
+	out_be32(host.token + dcr_n * host.stride, value);
+}
+
+extern u64 of_translate_dcr_address(struct device_node *dev,
+				    unsigned int dcr_n,
+				    unsigned int *stride);
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_POWERPC_DCR_MMIO_H */
+
+
Index: linux-cell/include/asm-powerpc/dcr-native.h
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-cell/include/asm-powerpc/dcr-native.h	2006-10-16 15:05:06.000000000 +1000
@@ -0,0 +1,39 @@
+/*
+ * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ *
+ *   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
+ */
+
+#ifndef _ASM_POWERPC_DCR_NATIVE_H
+#define _ASM_POWERPC_DCR_NATIVE_H
+#ifdef __KERNEL__
+
+#include <asm/reg.h>
+
+typedef struct {} dcr_host_t;
+
+#define DCR_MAP_OK(host)	(1)
+
+#define dcr_map(dev, dcr_n, dcr_c)	{}
+#define dcr_unmap(host, dcr_n, dcr_c)	{}
+#define dcr_read(host, dcr_n)		mfdcr(dcr_n)
+#define dcr_write(host, dcr_n, value)	mtdcr(dcr_n, value)
+
+
+#endif /* __KERNEL__ */
+#endif /* _ASM_POWERPC_DCR_NATIVE_H */
+
+
Index: linux-cell/arch/ppc/Kconfig
===================================================================
--- linux-cell.orig/arch/ppc/Kconfig	2006-10-16 15:05:04.000000000 +1000
+++ linux-cell/arch/ppc/Kconfig	2006-10-16 15:05:06.000000000 +1000
@@ -77,9 +77,11 @@ config 6xx
 
 config 40x
 	bool "40x"
+	select PPC_DCR_NATIVE
 
 config 44x
 	bool "44x"
+	select PPC_DCR_NATIVE
 
 config 8xx
 	bool "8xx"
@@ -95,6 +97,15 @@ endchoice
 config PPC_FPU
 	bool
 
+config PPC_DCR_NATIVE
+	bool
+	default n
+
+config PPC_DCR
+	bool
+	depends on PPC_DCR_NATIVE
+	default y
+
 config BOOKE
 	bool
 	depends on E200 || E500
Index: linux-cell/arch/powerpc/kernel/Makefile
===================================================================
--- linux-cell.orig/arch/powerpc/kernel/Makefile	2006-10-16 15:05:04.000000000 +1000
+++ linux-cell/arch/powerpc/kernel/Makefile	2006-10-16 15:05:06.000000000 +1000
@@ -60,6 +60,7 @@ obj-$(CONFIG_BOOTX_TEXT)	+= btext.o
 obj-$(CONFIG_SMP)		+= smp.o
 obj-$(CONFIG_KPROBES)		+= kprobes.o
 obj-$(CONFIG_PPC_UDBG_16550)	+= legacy_serial.o udbg_16550.o
+
 module-$(CONFIG_PPC64)		+= module_64.o
 obj-$(CONFIG_MODULES)		+= $(module-y)
 
Index: linux-cell/arch/powerpc/sysdev/Makefile
===================================================================
--- linux-cell.orig/arch/powerpc/sysdev/Makefile	2006-10-16 15:05:04.000000000 +1000
+++ linux-cell/arch/powerpc/sysdev/Makefile	2006-10-16 15:05:06.000000000 +1000
@@ -5,8 +5,7 @@ endif
 obj-$(CONFIG_MPIC)		+= mpic.o
 obj-$(CONFIG_PPC_INDIRECT_PCI)	+= indirect_pci.o
 obj-$(CONFIG_PPC_MPC106)	+= grackle.o
-obj-$(CONFIG_BOOKE)		+= dcr.o
-obj-$(CONFIG_40x)		+= dcr.o
+obj-$(CONFIG_PPC_DCR)		+= dcr.o dcr-low.o
 obj-$(CONFIG_U3_DART)		+= dart_iommu.o
 obj-$(CONFIG_MMIO_NVRAM)	+= mmio_nvram.o
 obj-$(CONFIG_FSL_SOC)		+= fsl_soc.o
Index: linux-cell/arch/powerpc/sysdev/dcr-low.S
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-cell/arch/powerpc/sysdev/dcr-low.S	2006-10-16 15:05:06.000000000 +1000
@@ -0,0 +1,39 @@
+/*
+ * "Indirect" DCR access
+ *
+ * Copyright (c) 2004 Eugene Surovegin <ebs@ebshome.net>
+ *
+ * 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.
+ */
+
+#include <asm/ppc_asm.h>
+#include <asm/processor.h>
+
+#define DCR_ACCESS_PROLOG(table) \
+	rlwinm  r3,r3,4,18,27;   \
+	lis     r5,table@h;      \
+	ori     r5,r5,table@l;   \
+	add     r3,r3,r5;        \
+	mtctr   r3;              \
+	bctr
+
+_GLOBAL(__mfdcr)
+	DCR_ACCESS_PROLOG(__mfdcr_table)
+
+_GLOBAL(__mtdcr)
+	DCR_ACCESS_PROLOG(__mtdcr_table)
+
+__mfdcr_table:
+	mfdcr  r3,0; blr
+__mtdcr_table:
+	mtdcr  0,r4; blr
+
+dcr     = 1
+        .rept   1023
+	mfdcr   r3,dcr; blr
+	mtdcr   dcr,r4; blr
+	dcr     = dcr + 1
+	.endr
Index: linux-cell/arch/powerpc/sysdev/dcr.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-cell/arch/powerpc/sysdev/dcr.c	2006-10-16 17:21:01.000000000 +1000
@@ -0,0 +1,134 @@
+/*
+ * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ *
+ *   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
+ */
+
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <asm/prom.h>
+#include <asm/dcr.h>
+
+unsigned int dcr_resource_start(struct device_node *np, unsigned int index)
+{
+	unsigned int ds;
+	const u32 *dr = get_property(np, "dcr-reg", &ds);
+
+	if (dr == NULL || ds & 1 || index >= (ds / 8))
+		return -EINVAL;
+
+	return dr[index * 2];
+}
+
+unsigned int dcr_resource_len(struct device_node *np, unsigned int index)
+{
+	unsigned int ds;
+	const u32 *dr = get_property(np, "dcr-reg", &ds);
+
+	if (dr == NULL || ds & 1 || index >= (ds / 8))
+		return -EINVAL;
+
+	return dr[index * 2 + 1];
+}
+
+#ifndef CONFIG_PPC_DCR_NATIVE
+
+static struct device_node * find_dcr_parent(struct device_node * node)
+{
+	struct device_node *par, *tmp;
+	const u32 *p;
+
+	for (par = of_node_get(node); par;) {
+		if (get_property(par, "dcr-controller", NULL))
+		    break;
+		p = get_property(par, "dcr-parent", NULL);
+		tmp = par;
+		if (p == NULL)
+			par = of_get_parent(par);
+		else
+			par = of_find_node_by_phandle(*p);
+		of_node_put(tmp);
+	}
+	return par;
+}
+
+u64 of_translate_dcr_address(struct device_node *dev,
+			     unsigned int dcr_n,
+			     unsigned int *stride)
+{
+	struct device_node *dp;
+	const u32 *p;
+	u64 ret;
+
+	dp = find_dcr_parent(dev);
+	if (dp == NULL)
+		return OF_BAD_ADDR;
+
+	/* Stride is not properly defined yet, default to 0x10 for Axon */
+	p = get_property(dp, "dcr-mmio-stride", NULL);
+	*stride = (p == NULL) ? 0x10 : *p;
+
+	/* XXX FIXME: Which property name is to use of the 2 following ? */
+	p = get_property(dp, "dcr-mmio-range", NULL);
+	if (p == NULL)
+		p = get_property(dp, "dcr-mmio-space", NULL);
+	if (p == NULL)
+		return OF_BAD_ADDR;
+
+	/* Maybe could do some better range checking here */
+	ret = of_translate_address(dp, p);
+	if (ret != OF_BAD_ADDR)
+		ret += (u64)(*stride) * (u64)dcr_n;
+	return ret;
+}
+
+dcr_host_t dcr_map(struct device_node *dev, unsigned int dcr_n,
+		   unsigned int dcr_c)
+{
+	dcr_host_t ret = { .token = NULL, .stride = 0 };
+	u64 addr;
+
+	pr_debug("dcr_map(%s, 0x%x, 0x%x)\n",
+		 dev->full_name, dcr_n, dcr_c);
+
+	addr = of_translate_dcr_address(dev, dcr_n, &ret.stride);
+	pr_debug("translates to addr: 0x%lx, stride: 0x%x\n",
+		 addr, ret.stride);
+	if (addr == OF_BAD_ADDR)
+		return ret;
+	pr_debug("mapping 0x%x bytes\n", dcr_c * ret.stride);
+	ret.token = ioremap(addr, dcr_c * ret.stride);
+	if (ret.token == NULL)
+		return ret;
+	pr_debug("mapped at 0x%p -> base is 0x%p\n",
+		 ret.token, ret.token - dcr_n * ret.stride);
+	ret.token -= dcr_n * ret.stride;
+	return ret;
+}
+
+void dcr_unmap(dcr_host_t host, unsigned int dcr_n, unsigned int dcr_c)
+{
+	dcr_host_t h = host;
+
+	if (h.token == NULL)
+		return;
+	h.token -= dcr_n * h.stride;
+	iounmap(h.token);
+	h.token = NULL;
+}
+
+#endif /* !defined(CONFIG_PPC_DCR_NATIVE) */

Re: [PATCH] powerpc: New DCR access methods

[Christoph Hellwig]

On Mon, Oct 16, 2006 at 05:44:58PM +1000, Benjamin Herrenschmidt wrote:
> This patch adds new dcr_map/dcr_read/dcr_write accessors for DCRs that
> can be used by drivers to transparently address either native DCRs or
> memory mapped DCRs. The implementation for memory mapped DCRs is done
> after the binding being currently worked on for SLOF and the Axon
> chipset. This patch enables it for the cell native platform
> 
> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> 
> Index: linux-cell/include/asm-powerpc/dcr.h
> ===================================================================
> --- /dev/null	1970-01-01 00:00:00.000000000 +0000
> +++ linux-cell/include/asm-powerpc/dcr.h	2006-10-16 16:42:32.000000000 +1000
> @@ -0,0 +1,42 @@
> +/*
> + * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
> + *                    <benh@kernel.crashing.org>
> + *
> + *   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
> + */
> +
> +#ifndef _ASM_POWERPC_DCR_H
> +#define _ASM_POWERPC_DCR_H
> +#ifdef __KERNEL__
> +
> +#ifdef CONFIG_PPC_DCR_NATIVE
> +#include <asm/dcr-native.h>
> +#else
> +#include <asm/dcr-mmio.h>
> +#endif

Having this as a compile-time switch seems broken.  I thought the plan was
to support all different 64bit kernels with a single kernel binary?

Re: [PATCH] powerpc: New DCR access methods

[Benjamin Herrenschmidt]

> > +#ifdef CONFIG_PPC_DCR_NATIVE
> > +#include <asm/dcr-native.h>
> > +#else
> > +#include <asm/dcr-mmio.h>
> > +#endif
> 
> Having this as a compile-time switch seems broken.  I thought the plan was
> to support all different 64bit kernels with a single kernel binary?

"native" DCRs only exist in 32 bits 4xx / BookE processors as of today.

Basically, those processors have mtdcr and mfdcr instructions to access
those special "registers". They are in fact connected to a bus to
control various IOs. On AXON (and possibly other future chips), since
the host processor doesn't have those instructions, they are memory
mapped.

There is currently no way you can have both in the same kernel. If that
ever happens, then the "mmio" version could easily be tweaked to deal
with both. However, the "native only" implementation is useful for
embedded 4xx etc... as it resolves directly to mfdcr/mtdcr instructions,
dcr_map is an empty macro, etc... thus there is 0 overhead of switching
4xx code to the new dcr accessors.

Ben.