// SPDX-License-Identifier: GPL-2.0-or-later /* * 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 */ #include #include #include #include #include #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 >= 0) ug_raw_putc(ch); } /* * 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. */ static 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 *__init ug_udbg_setup_exi_io_base(struct device_node *np) { void __iomem *exi_io_base = NULL; 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) exi_io_base = ioremap(paddr, reg[1]); } return exi_io_base; } /* * Checks if a USB Gecko adapter is inserted in any memory card slot. */ static void __iomem *__init ug_udbg_probe(void __iomem *exi_io_base) { int i; /* look for a usbgecko on memcard slots A and B */ for (i = 0; i < 2; i++) { ug_io_base = exi_io_base + 0x14 * i; if (ug_is_adapter_present()) break; } if (i == 2) ug_io_base = NULL; return ug_io_base; } /* * USB Gecko udbg support initialization. */ void __init ug_udbg_init(void) { struct device_node *np; void __iomem *exi_io_base; if (ug_io_base) udbg_printf("%s: early -> final\n", __func__); np = of_find_compatible_node(NULL, NULL, "nintendo,flipper-exi"); if (!np) { udbg_printf("%s: EXI node not found\n", __func__); goto out; } exi_io_base = ug_udbg_setup_exi_io_base(np); if (!exi_io_base) { udbg_printf("%s: failed to setup EXI io base\n", __func__); goto done; } if (!ug_udbg_probe(exi_io_base)) { udbg_printf("usbgecko_udbg: not found\n"); iounmap(exi_io_base); } 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: of_node_put(np); out: return; } #ifdef CONFIG_PPC_EARLY_DEBUG_USBGECKO static phys_addr_t __init ug_early_grab_io_addr(void) { #if defined(CONFIG_GAMECUBE) return 0x0c000000; #elif defined(CONFIG_WII) return 0x0d000000; #else #error Invalid platform for USB Gecko based early debugging. #endif } /* * USB Gecko early debug support initialization for udbg. */ void __init udbg_init_usbgecko(void) { void __iomem *early_debug_area; void __iomem *exi_io_base; /* * At this point we have a BAT already setup that enables I/O * to the EXI hardware. * * The BAT uses a virtual address range reserved at the fixmap. * This must match the virtual address configured in * head_32.S:setup_usbgecko_bat(). */ early_debug_area = (void __iomem *)__fix_to_virt(FIX_EARLY_DEBUG_BASE); exi_io_base = early_debug_area + 0x00006800; /* try to detect a USB Gecko */ if (!ug_udbg_probe(exi_io_base)) return; /* we found a USB Gecko, load udbg hooks */ udbg_putc = ug_udbg_putc; udbg_getc = ug_udbg_getc; udbg_getc_poll = ug_udbg_getc_poll; /* * Prepare again the same BAT for MMU_init. * This allows udbg I/O to continue working after the MMU is * turned on for real. * It is safe to continue using the same virtual address as it is * a reserved fixmap area. */ setbat(1, (unsigned long)early_debug_area, ug_early_grab_io_addr(), 128*1024, PAGE_KERNEL_NCG); } #endif /* CONFIG_PPC_EARLY_DEBUG_USBGECKO */