325 lines
6.5 KiB
C
325 lines
6.5 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* arch/powerpc/platforms/embedded6xx/usbgecko_udbg.c
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*
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* udbg serial input/output routines for the USB Gecko adapter.
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* Copyright (C) 2008-2009 The GameCube Linux Team
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* Copyright (C) 2008,2009 Albert Herranz
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*/
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#include <linux/of_address.h>
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#include <mm/mmu_decl.h>
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#include <asm/io.h>
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#include <asm/udbg.h>
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#include <asm/fixmap.h>
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#include "usbgecko_udbg.h"
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#define EXI_CLK_32MHZ 5
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#define EXI_CSR 0x00
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#define EXI_CSR_CLKMASK (0x7<<4)
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#define EXI_CSR_CLK_32MHZ (EXI_CLK_32MHZ<<4)
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#define EXI_CSR_CSMASK (0x7<<7)
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#define EXI_CSR_CS_0 (0x1<<7) /* Chip Select 001 */
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#define EXI_CR 0x0c
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#define EXI_CR_TSTART (1<<0)
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#define EXI_CR_WRITE (1<<2)
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#define EXI_CR_READ_WRITE (2<<2)
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#define EXI_CR_TLEN(len) (((len)-1)<<4)
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#define EXI_DATA 0x10
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#define UG_READ_ATTEMPTS 100
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#define UG_WRITE_ATTEMPTS 100
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static void __iomem *ug_io_base;
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/*
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* Performs one input/output transaction between the exi host and the usbgecko.
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*/
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static u32 ug_io_transaction(u32 in)
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{
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u32 __iomem *csr_reg = ug_io_base + EXI_CSR;
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u32 __iomem *data_reg = ug_io_base + EXI_DATA;
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u32 __iomem *cr_reg = ug_io_base + EXI_CR;
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u32 csr, data, cr;
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/* select */
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csr = EXI_CSR_CLK_32MHZ | EXI_CSR_CS_0;
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out_be32(csr_reg, csr);
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/* read/write */
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data = in;
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out_be32(data_reg, data);
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cr = EXI_CR_TLEN(2) | EXI_CR_READ_WRITE | EXI_CR_TSTART;
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out_be32(cr_reg, cr);
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while (in_be32(cr_reg) & EXI_CR_TSTART)
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barrier();
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/* deselect */
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out_be32(csr_reg, 0);
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/* result */
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data = in_be32(data_reg);
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return data;
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}
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/*
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* Returns true if an usbgecko adapter is found.
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*/
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static int ug_is_adapter_present(void)
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{
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if (!ug_io_base)
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return 0;
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return ug_io_transaction(0x90000000) == 0x04700000;
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}
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/*
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* Returns true if the TX fifo is ready for transmission.
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*/
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static int ug_is_txfifo_ready(void)
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{
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return ug_io_transaction(0xc0000000) & 0x04000000;
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}
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/*
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* Tries to transmit a character.
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* If the TX fifo is not ready the result is undefined.
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*/
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static void ug_raw_putc(char ch)
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{
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ug_io_transaction(0xb0000000 | (ch << 20));
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}
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/*
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* Transmits a character.
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* It silently fails if the TX fifo is not ready after a number of retries.
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*/
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static void ug_putc(char ch)
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{
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int count = UG_WRITE_ATTEMPTS;
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if (!ug_io_base)
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return;
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if (ch == '\n')
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ug_putc('\r');
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while (!ug_is_txfifo_ready() && count--)
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barrier();
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if (count >= 0)
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ug_raw_putc(ch);
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}
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/*
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* Returns true if the RX fifo is ready for transmission.
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*/
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static int ug_is_rxfifo_ready(void)
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{
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return ug_io_transaction(0xd0000000) & 0x04000000;
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}
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/*
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* Tries to receive a character.
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* If a character is unavailable the function returns -1.
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*/
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static int ug_raw_getc(void)
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{
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u32 data = ug_io_transaction(0xa0000000);
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if (data & 0x08000000)
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return (data >> 16) & 0xff;
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else
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return -1;
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}
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/*
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* Receives a character.
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* It fails if the RX fifo is not ready after a number of retries.
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*/
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static int ug_getc(void)
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{
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int count = UG_READ_ATTEMPTS;
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if (!ug_io_base)
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return -1;
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while (!ug_is_rxfifo_ready() && count--)
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barrier();
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return ug_raw_getc();
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}
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/*
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* udbg functions.
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*
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*/
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/*
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* Transmits a character.
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*/
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static void ug_udbg_putc(char ch)
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{
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ug_putc(ch);
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}
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/*
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* Receives a character. Waits until a character is available.
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*/
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static int ug_udbg_getc(void)
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{
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int ch;
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while ((ch = ug_getc()) == -1)
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barrier();
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return ch;
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}
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/*
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* Receives a character. If a character is not available, returns -1.
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*/
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static int ug_udbg_getc_poll(void)
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{
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if (!ug_is_rxfifo_ready())
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return -1;
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return ug_getc();
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}
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/*
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* Retrieves and prepares the virtual address needed to access the hardware.
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*/
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static void __iomem *__init ug_udbg_setup_exi_io_base(struct device_node *np)
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{
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void __iomem *exi_io_base = NULL;
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phys_addr_t paddr;
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const unsigned int *reg;
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reg = of_get_property(np, "reg", NULL);
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if (reg) {
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paddr = of_translate_address(np, reg);
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if (paddr)
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exi_io_base = ioremap(paddr, reg[1]);
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}
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return exi_io_base;
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}
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/*
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* Checks if a USB Gecko adapter is inserted in any memory card slot.
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*/
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static void __iomem *__init ug_udbg_probe(void __iomem *exi_io_base)
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{
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int i;
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/* look for a usbgecko on memcard slots A and B */
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for (i = 0; i < 2; i++) {
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ug_io_base = exi_io_base + 0x14 * i;
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if (ug_is_adapter_present())
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break;
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}
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if (i == 2)
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ug_io_base = NULL;
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return ug_io_base;
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}
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/*
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* USB Gecko udbg support initialization.
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*/
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void __init ug_udbg_init(void)
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{
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struct device_node *np;
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void __iomem *exi_io_base;
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if (ug_io_base)
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udbg_printf("%s: early -> final\n", __func__);
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np = of_find_compatible_node(NULL, NULL, "nintendo,flipper-exi");
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if (!np) {
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udbg_printf("%s: EXI node not found\n", __func__);
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goto out;
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}
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exi_io_base = ug_udbg_setup_exi_io_base(np);
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if (!exi_io_base) {
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udbg_printf("%s: failed to setup EXI io base\n", __func__);
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goto done;
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}
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if (!ug_udbg_probe(exi_io_base)) {
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udbg_printf("usbgecko_udbg: not found\n");
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iounmap(exi_io_base);
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} else {
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udbg_putc = ug_udbg_putc;
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udbg_getc = ug_udbg_getc;
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udbg_getc_poll = ug_udbg_getc_poll;
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udbg_printf("usbgecko_udbg: ready\n");
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}
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done:
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of_node_put(np);
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out:
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return;
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}
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#ifdef CONFIG_PPC_EARLY_DEBUG_USBGECKO
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static phys_addr_t __init ug_early_grab_io_addr(void)
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{
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#if defined(CONFIG_GAMECUBE)
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return 0x0c000000;
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#elif defined(CONFIG_WII)
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return 0x0d000000;
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#else
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#error Invalid platform for USB Gecko based early debugging.
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#endif
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}
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/*
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* USB Gecko early debug support initialization for udbg.
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*/
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void __init udbg_init_usbgecko(void)
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{
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void __iomem *early_debug_area;
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void __iomem *exi_io_base;
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/*
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* At this point we have a BAT already setup that enables I/O
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* to the EXI hardware.
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*
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* The BAT uses a virtual address range reserved at the fixmap.
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* This must match the virtual address configured in
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* head_32.S:setup_usbgecko_bat().
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*/
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early_debug_area = (void __iomem *)__fix_to_virt(FIX_EARLY_DEBUG_BASE);
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exi_io_base = early_debug_area + 0x00006800;
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/* try to detect a USB Gecko */
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if (!ug_udbg_probe(exi_io_base))
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return;
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/* we found a USB Gecko, load udbg hooks */
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udbg_putc = ug_udbg_putc;
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udbg_getc = ug_udbg_getc;
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udbg_getc_poll = ug_udbg_getc_poll;
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/*
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* Prepare again the same BAT for MMU_init.
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* This allows udbg I/O to continue working after the MMU is
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* turned on for real.
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* It is safe to continue using the same virtual address as it is
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* a reserved fixmap area.
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*/
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setbat(1, (unsigned long)early_debug_area,
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ug_early_grab_io_addr(), 128*1024, PAGE_KERNEL_NCG);
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}
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#endif /* CONFIG_PPC_EARLY_DEBUG_USBGECKO */
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