gamecube/wii: graphic quantization registers driver (GQR)

Add support for accessing the Graphic Quantization Registers of the
Nintendo GameCube and Wii video game consoles PowerPC processor via
the proc filesystem.

The Graphic Quantization Registers can be used to influence how the
psql* and psqst* instructions operate.

Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>

drivers/misc/Kconfig

@@ -55,6 +55,15 @@ config ATMEL_TCB_CLKSRC_BLOCK
 	  TC can be used for other purposes, such as PWM generation and
 	  interval timing.
 
+config GAMECUBE_GQR
+	tristate "Nintendo GameCube/Wii Graphic Quantization Registers (GQR)"
+	depends on GAMECUBE_COMMON
+	help
+          This option enables device driver support for the Gekko/Broadway
+	  processors' Graphic Quantization Registers.
+	  These registers are used with the psql and psqst instructions.
+	  The registers will appear in /proc/sys/gqr.
+
 config IBM_ASM
 	tristate "Device driver for IBM RSA service processor"
 	depends on X86 && PCI && INPUT && EXPERIMENTAL

drivers/misc/Makefile

@@ -21,5 +21,6 @@ obj-$(CONFIG_HP_ILO)		+= hpilo.o
 obj-$(CONFIG_ISL29003)		+= isl29003.o
 obj-$(CONFIG_EP93XX_PWM)	+= ep93xx_pwm.o
 obj-$(CONFIG_C2PORT)		+= c2port/
+obj-$(CONFIG_GAMECUBE_GQR)	+= gcn-gqr.o
 obj-y				+= eeprom/
 obj-y				+= cb710/

drivers/misc/gcn-gqr.c

@@ -0,0 +1,129 @@
+/*
+ * drivers/misc/gcn-gqr.c
+ *
+ * Nintendo GameCube GQR driver
+ * Copyright (C) 2004-2009 The GameCube Linux Team
+ * Copyright (C) 2004 Todd Jeffreys <todd@voidpointer.org>
+ * Copyright (C) 2007,2008,2009 Albert Herranz
+ *
+ * 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 <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/ctype.h>
+#include <linux/sysctl.h>
+#include <linux/types.h>
+#include <linux/uaccess.h>
+
+static u32 gqr_values[8];
+static struct ctl_table_header *gqr_table_header;
+
+#define SPR_GQR0 912
+#define SPR_GQR1 913
+#define SPR_GQR2 914
+#define SPR_GQR3 915
+#define SPR_GQR4 916
+#define SPR_GQR5 917
+#define SPR_GQR6 918
+#define SPR_GQR7 919
+
+#define MFSPR_CASE(i) case (i): (*((u32 *)table->data) = mfspr(SPR_GQR##i))
+#define MTSPR_CASE(i) case (i): mtspr(SPR_GQR##i, *((u32 *)table->data))
+
+static int proc_dogqr(ctl_table *table, int write, struct file *file,
+		      void __user *buffer, size_t *lenp, loff_t *ppos)
+{
+	int r;
+
+	if (!write) {		/* if they are reading, update the variable */
+		switch (table->data - (void *)gqr_values) {
+			MFSPR_CASE(0); break;
+			MFSPR_CASE(1); break;
+			MFSPR_CASE(2); break;
+			MFSPR_CASE(3); break;
+			MFSPR_CASE(4); break;
+			MFSPR_CASE(5); break;
+			MFSPR_CASE(6); break;
+			MFSPR_CASE(7); break;
+		default:
+			return -EFAULT;	/* shouldn't happen */
+		}
+	}
+
+	r = proc_dointvec(table, write, file, buffer, lenp, ppos);
+
+	if ((r == 0) && write) {  /* if they are writing, update the reg */
+		switch (table->data - (void *)gqr_values) {
+			MTSPR_CASE(0); break;
+			MTSPR_CASE(1); break;
+			MTSPR_CASE(2); break;
+			MTSPR_CASE(3); break;
+			MTSPR_CASE(4); break;
+			MTSPR_CASE(5); break;
+			MTSPR_CASE(6); break;
+			MTSPR_CASE(7); break;
+		default:
+			return -EFAULT;	/* shouldn't happen */
+		}
+	}
+
+	return r;
+}
+
+#define DECLARE_GQR(i) {  \
+		.ctl_name     = CTL_UNNUMBERED,       \
+		.procname     = "gqr" #i,         \
+		.data         = gqr_values + i,   \
+		.maxlen       = sizeof(int),      \
+		.mode         = 0644,             \
+		.proc_handler = &proc_dogqr       \
+	}
+
+static ctl_table gqr_members[] = {
+	DECLARE_GQR(0),
+	DECLARE_GQR(1),
+	DECLARE_GQR(2),
+	DECLARE_GQR(3),
+	DECLARE_GQR(4),
+	DECLARE_GQR(5),
+	DECLARE_GQR(6),
+	DECLARE_GQR(7),
+	{ .ctl_name = 0 }
+};
+
+static ctl_table gqr_table[] = {
+	{
+		.ctl_name = CTL_UNNUMBERED,
+		.procname = "gqr",
+		.mode     = 0555,
+		.child    = gqr_members,
+	},
+	{ .ctl_name = 0 }
+};
+
+int __init gcngqr_init(void)
+{
+	gqr_table_header = register_sysctl_table(gqr_table);
+	if (!gqr_table_header) {
+		printk(KERN_ERR "Unable to register GQR sysctl table\n");
+		return -ENOMEM;
+	}
+	return 0;
+}
+
+void __exit gcngqr_exit(void)
+{
+	unregister_sysctl_table(gqr_table_header);
+}
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Todd Jeffreys <todd@voidpointer.org>");
+module_init(gcngqr_init);
+module_exit(gcngqr_exit);