[RFC PATCH 09/19] powerpc: gamecube/wii: udbg support for usbgecko

[Albert Herranz <albert_herranz@yahoo.es>]

Add support for using the USB Gecko adapter via the udbg facility on
the Nintendo GameCube and Wii video game consoles.
The USB Gecko is a 3rd party memory card interface adapter that provides
a EXI (External Interface) to USB serial converter.

Signed-off-by: Albert Herranz <albert_herranz@yahoo.es>
---
 arch/powerpc/platforms/embedded6xx/Kconfig         |   13 +
 arch/powerpc/platforms/embedded6xx/Makefile        |    1 +
 arch/powerpc/platforms/embedded6xx/usbgecko_udbg.c |  285 ++++++++++++++++++++
 arch/powerpc/platforms/embedded6xx/usbgecko_udbg.h |   30 ++
 4 files changed, 329 insertions(+), 0 deletions(-)
 create mode 100644 arch/powerpc/platforms/embedded6xx/usbgecko_udbg.c
 create mode 100644 arch/powerpc/platforms/embedded6xx/usbgecko_udbg.h

diff --git a/arch/powerpc/platforms/embedded6xx/Kconfig b/arch/powerpc/platforms/embedded6xx/Kconfig
index 31487e4..bfd88be 100644
--- a/arch/powerpc/platforms/embedded6xx/Kconfig
+++ b/arch/powerpc/platforms/embedded6xx/Kconfig
@@ -95,3 +95,16 @@ config GAMECUBE_COMMON
 	bool
 	select NOT_COHERENT_CACHE
 
+config USBGECKO_UDBG
+	bool "USB Gecko udbg console for the Nintendo GameCube/Wii"
+	depends on GAMECUBE_COMMON
+	help
+	  If you say yes to this option, support will be included for the
+	  USB Gecko adapter as an udbg console.
+	  The USB Gecko is a EXI to USB Serial converter that can be plugged
+	  into a memcard slot in the Nintendo GameCube/Wii.
+
+	  This driver bypasses the EXI layer completely.
+
+	  If in doubt, say N here.
+
diff --git a/arch/powerpc/platforms/embedded6xx/Makefile b/arch/powerpc/platforms/embedded6xx/Makefile
index 0773c08..0ab7492 100644
--- a/arch/powerpc/platforms/embedded6xx/Makefile
+++ b/arch/powerpc/platforms/embedded6xx/Makefile
@@ -7,3 +7,4 @@ obj-$(CONFIG_STORCENTER)	+= storcenter.o
 obj-$(CONFIG_PPC_HOLLY)		+= holly.o
 obj-$(CONFIG_PPC_PRPMC2800)	+= prpmc2800.o
 obj-$(CONFIG_PPC_C2K)		+= c2k.o
+obj-$(CONFIG_USBGECKO_UDBG)	+= usbgecko_udbg.o
diff --git a/arch/powerpc/platforms/embedded6xx/usbgecko_udbg.c b/arch/powerpc/platforms/embedded6xx/usbgecko_udbg.c
new file mode 100644
index 0000000..49f86e8
--- /dev/null
+++ b/arch/powerpc/platforms/embedded6xx/usbgecko_udbg.c
@@ -0,0 +1,285 @@
+/*
+ * arch/powerpc/platforms/embedded6xx/usbgecko_udbg.c
+ *
+ * udbg serial input/output routines for the USB Gecko adapter.
+ * Copyright (C) 2008-2009 The GameCube Linux Team
+ * Copyright (C) 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 <asm/io.h>
+#include <asm/prom.h>
+#include <asm/udbg.h>
+
+#include <mm/mmu_decl.h>
+
+#include "usbgecko_udbg.h"
+
+
+#define EXI_CLK_32MHZ           5
+
+#define EXI_CSR                 0x00
+#define   EXI_CSR_CLKMASK       (0x7<<4)
+#define     EXI_CSR_CLK_32MHZ   (EXI_CLK_32MHZ<<4)
+#define   EXI_CSR_CSMASK        (0x7<<7)
+#define     EXI_CSR_CS_0        (0x1<<7)  /* Chip Select 001 */
+
+#define EXI_CR                  0x0c
+#define   EXI_CR_TSTART         (1<<0)
+#define   EXI_CR_WRITE		(1<<2)
+#define   EXI_CR_READ_WRITE     (2<<2)
+#define   EXI_CR_TLEN(len)      (((len)-1)<<4)
+
+#define EXI_DATA                0x10
+
+#define UG_READ_ATTEMPTS	100
+#define UG_WRITE_ATTEMPTS	100
+
+
+static void __iomem *ug_io_base;
+
+/*
+ * Performs one input/output transaction between the exi host and the usbgecko.
+ */
+static u32 ug_io_transaction(u32 in)
+{
+	u32 __iomem *csr_reg = ug_io_base + EXI_CSR;
+	u32 __iomem *data_reg = ug_io_base + EXI_DATA;
+	u32 __iomem *cr_reg = ug_io_base + EXI_CR;
+	u32 csr, data, cr;
+
+	/* select */
+	csr = EXI_CSR_CLK_32MHZ | EXI_CSR_CS_0;
+	out_be32(csr_reg, csr);
+
+	/* read/write */
+	data = in;
+	out_be32(data_reg, data);
+	cr = EXI_CR_TLEN(2) | EXI_CR_READ_WRITE | EXI_CR_TSTART;
+	out_be32(cr_reg, cr);
+
+	while (in_be32(cr_reg) & EXI_CR_TSTART)
+		barrier();
+
+	/* deselect */
+	out_be32(csr_reg, 0);
+
+	/* result */
+	data = in_be32(data_reg);
+
+	return data;
+}
+
+/*
+ * Returns true if an usbgecko adapter is found.
+ */
+static int ug_is_adapter_present(void)
+{
+	if (!ug_io_base)
+		return 0;
+
+	return ug_io_transaction(0x90000000) == 0x04700000;
+}
+
+/*
+ * Returns true if the TX fifo is ready for transmission.
+ */
+static int ug_is_txfifo_ready(void)
+{
+	return ug_io_transaction(0xc0000000) & 0x04000000;
+}
+
+/*
+ * Tries to transmit a character.
+ * If the TX fifo is not ready the result is undefined.
+ */
+static void ug_raw_putc(char ch)
+{
+	ug_io_transaction(0xb0000000 | (ch << 20));
+}
+
+/*
+ * Transmits a character.
+ * It silently fails if the TX fifo is not ready after a number of retries.
+ */
+static void ug_putc(char ch)
+{
+	int count = UG_WRITE_ATTEMPTS;
+
+	if (!ug_io_base)
+		return;
+
+	if (ch == '\n')
+		ug_putc('\r');
+
+	while (!ug_is_txfifo_ready() && count--)
+		barrier();
+	if (count)
+		ug_raw_putc(ch);
+}
+
+#if 0
+/*
+ * Trasmits a null terminated character string.
+ */
+static void ug_puts(char *s)
+{
+	while (*s)
+		ug_putc(*s++);
+}
+#endif
+
+/*
+ * Returns true if the RX fifo is ready for transmission.
+ */
+static int ug_is_rxfifo_ready(void)
+{
+	return ug_io_transaction(0xd0000000) & 0x04000000;
+}
+
+/*
+ * Tries to receive a character.
+ * If a character is unavailable the function returns -1.
+ */
+static int ug_raw_getc(void)
+{
+	u32 data = ug_io_transaction(0xa0000000);
+	if (data & 0x08000000)
+		return (data >> 16) & 0xff;
+	else
+		return -1;
+}
+
+/*
+ * Receives a character.
+ * It fails if the RX fifo is not ready after a number of retries.
+ */
+static int ug_getc(void)
+{
+	int count = UG_READ_ATTEMPTS;
+
+	if (!ug_io_base)
+		return -1;
+
+	while (!ug_is_rxfifo_ready() && count--)
+		barrier();
+	return ug_raw_getc();
+}
+
+/*
+ * udbg functions.
+ *
+ */
+
+/*
+ * Transmits a character.
+ */
+void ug_udbg_putc(char ch)
+{
+	ug_putc(ch);
+}
+
+/*
+ * Receives a character. Waits until a character is available.
+ */
+static int ug_udbg_getc(void)
+{
+	int ch;
+
+	while ((ch = ug_getc()) == -1)
+		barrier();
+	return ch;
+}
+
+/*
+ * Receives a character. If a character is not available, returns -1.
+ */
+static int ug_udbg_getc_poll(void)
+{
+	if (!ug_is_rxfifo_ready())
+		return -1;
+	return ug_getc();
+}
+
+/*
+ * Retrieves and prepares the virtual address needed to access the hardware.
+ */
+static void __iomem *ug_udbg_setup_io_base(struct device_node *np)
+{
+	phys_addr_t paddr;
+	const unsigned int *reg;
+
+	reg = of_get_property(np, "reg", NULL);
+	if (reg) {
+		paddr = of_translate_address(np, reg);
+		if (paddr) {
+			ug_io_base = ioremap(paddr, reg[1]);
+			return ug_io_base;
+		}
+	}
+	return NULL;
+}
+
+/*
+ * USB Gecko udbg support initialization.
+ */
+void __init ug_udbg_init(void)
+{
+	struct device_node *np = NULL;
+	struct device_node *stdout;
+	const char *path;
+
+	if (!of_chosen) {
+		udbg_printf("%s: missing of_chosen\n", __func__);
+		goto done;
+	}
+
+	path = of_get_property(of_chosen, "linux,stdout-path", NULL);
+	if (!path) {
+		udbg_printf("%s: missing %s property", __func__,
+			    "linux,stdout-path");
+		goto done;
+	}
+
+	stdout = of_find_node_by_path(path);
+	if (!stdout) {
+		udbg_printf("%s: missing path %s", __func__, path);
+		goto done;
+	}
+
+	for (np = NULL;
+	    (np = of_find_compatible_node(np, NULL, "usbgecko,usbgecko"));)
+		if (np == stdout)
+			break;
+
+	of_node_put(stdout);
+	if (!np) {
+		udbg_printf("%s: stdout is not an usbgecko", __func__);
+		goto done;
+	}
+
+	if (!ug_udbg_setup_io_base(np)) {
+		udbg_printf("%s: failed to setup io base", __func__);
+		goto done;
+	}
+
+	if (!ug_is_adapter_present()) {
+		udbg_printf("usbgecko_udbg: not found\n");
+		ug_io_base = NULL;
+	} else {
+		udbg_putc = ug_udbg_putc;
+		udbg_getc = ug_udbg_getc;
+		udbg_getc_poll = ug_udbg_getc_poll;
+		udbg_printf("usbgecko_udbg: ready\n");
+	}
+
+done:
+	if (np)
+		of_node_put(np);
+	return;
+}
diff --git a/arch/powerpc/platforms/embedded6xx/usbgecko_udbg.h b/arch/powerpc/platforms/embedded6xx/usbgecko_udbg.h
new file mode 100644
index 0000000..3929de3
--- /dev/null
+++ b/arch/powerpc/platforms/embedded6xx/usbgecko_udbg.h
@@ -0,0 +1,30 @@
+/*
+ * arch/powerpc/platforms/embedded6xx/usbgecko_udbg.h
+ *
+ * udbg serial input/output routines for the USB Gecko adapter.
+ * Copyright (C) 2008-2009 The GameCube Linux Team
+ * Copyright (C) 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.
+ *
+ */
+
+#ifndef __USBGECKO_UDBG_H
+#define __USBGECKO_UDBG_H
+
+#ifdef CONFIG_USBGECKO_UDBG
+
+extern void __init ug_udbg_init(void);
+
+#else
+
+static inline void __init ug_udbg_init(void)
+{
+}
+
+#endif /* CONFIG_USBGECKO_UDBG */
+
+#endif /* __USBGECKO_UDBG_H */
-- 
1.6.3.3