diff options
| author | Stefan Roese <sr@denx.de> | 2016-01-19 13:05:10 (GMT) |
|---|---|---|
| committer | Bin Meng <bmeng.cn@gmail.com> | 2016-01-28 05:53:30 (GMT) |
| commit | 85056932f2bad4b6749d42c983d2219ae70fa741 (patch) | |
| tree | c0276be83cb5e34692eaca6ffcf45f6bf8667146 /drivers/misc/winbond_w83627.c | |
| parent | 0a34a5fd2794a87c43e8d009ccb711e6839843b2 (diff) | |
| download | u-boot-85056932f2bad4b6749d42c983d2219ae70fa741.tar.xz | |
misc: Add simple driver to enable the legacy UART on Winbond Super IO chips
On most x86 boards, the legacy serial ports (io address 0x3f8/0x2f8)
are provided by a superio chip connected to the LPC bus. We must
program the superio chip so that serial ports are available for us.
Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Bin Meng <bmeng.cn@gmail.com>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Diffstat (limited to 'drivers/misc/winbond_w83627.c')
| -rw-r--r-- | drivers/misc/winbond_w83627.c | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/drivers/misc/winbond_w83627.c b/drivers/misc/winbond_w83627.c new file mode 100644 index 0000000..59db7d9 --- /dev/null +++ b/drivers/misc/winbond_w83627.c @@ -0,0 +1,41 @@ +/* + * Copyright (C) 2016 Stefan Roese <sr@denx.de> + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <common.h> +#include <asm/io.h> +#include <asm/pnp_def.h> + +#define WINBOND_ENTRY_KEY 0x87 +#define WINBOND_EXIT_KEY 0xaa + +/* Enable configuration: pass entry key '0x87' into index port dev twice */ +static void pnp_enter_conf_state(u16 dev) +{ + u16 port = dev >> 8; + + outb(WINBOND_ENTRY_KEY, port); + outb(WINBOND_ENTRY_KEY, port); +} + +/* Disable configuration: pass exit key '0xAA' into index port dev */ +static void pnp_exit_conf_state(u16 dev) +{ + u16 port = dev >> 8; + + outb(WINBOND_EXIT_KEY, port); +} + +/* Bring up early serial debugging output before the RAM is initialized */ +void winbond_enable_serial(uint dev, uint iobase, uint irq) +{ + pnp_enter_conf_state(dev); + pnp_set_logical_device(dev); + pnp_set_enable(dev, 0); + pnp_set_iobase(dev, PNP_IDX_IO0, iobase); + pnp_set_irq(dev, PNP_IDX_IRQ0, irq); + pnp_set_enable(dev, 1); + pnp_exit_conf_state(dev); +} |