// 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 <linux/of_address.h>
#include <mm/mmu_decl.h>
#include <asm/io.h>
#include <asm/udbg.h>
#include <asm/fixmap.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 >= 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();
}
/*
* 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 = of_iomap(np, 0);
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 */