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serial: ns16550: Support run-time configuration 

At present this driver uses an assortment of CONFIG options to control
how it accesses the hardware. This is painful for platforms that are
supposed to be controlled by a device tree or a previous-stage bootloader.

Add a new CONFIG option to enable fully dynamic configuration. This
controls register spacing, size, offset and endianness.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Aiden Park <aiden.park@intel.com>
Tested-by: Aiden Park <aiden.park@intel.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
[bmeng: squashed in http://patchwork.ozlabs.org/patch/1232929/]
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
This commit is contained in:
Simon Glass 2019-12-19 17:58:18 -07:00 committed by Bin Meng
parent 31a790bee9
commit 62cbde4c4e
3 changed files with 107 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/serial/Kconfig
View File

@ -601,6 +601,27 @@ config SYS_NS16550
be used. It can be a constant or a function to get clock, eg,
get_serial_clock().
config NS16550_DYNAMIC
bool "Allow NS16550 to be configured at runtime"
default y if SYS_COREBOOT || SYS_SLIMBOOTLOADER
help
Enable this option to allow device-tree control of the driver.
Normally this driver is controlled by the following options:
CONFIG_SYS_NS16550_PORT_MAPPED - indicates that port I/O is used for
access. If not enabled, then the UART is memory-mapped.
CONFIG_SYS_NS16550_MEM32 - if memory-mapped, indicates that 32-bit
access should be used (instead of 8-bit)
CONFIG_SYS_NS16550_REG_SIZE - indicates register width and also
endianness. If positive, big-endian access is used. If negative,
little-endian is used.
It is not a good practice for a driver to be statically configured,
since it prevents the same driver being used for different types of
UARTs in a system. This option avoids this problem at the cost of a
slightly increased code size.
config INTEL_MID_SERIAL
bool "Intel MID platform UART support"
depends on DM_SERIAL && OF_CONTROL

79
drivers/serial/ns16550.c
View File

@ -93,19 +93,79 @@ static inline int serial_in_shift(void *addr, int shift)
#define CONFIG_SYS_NS16550_CLK 0
#endif
/*
* Use this #ifdef for now since many platforms don't define in(), out(),
* out_le32(), etc. but we don't have #defines to indicate this.
*
* TODO(sjg@chromium.org): Add CONFIG options to indicate what I/O is available
* on a platform
*/
#ifdef CONFIG_NS16550_DYNAMIC
static void serial_out_dynamic(struct ns16550_platdata *plat, u8 *addr,
int value)
{
if (plat->flags & NS16550_FLAG_IO) {
outb(value, addr);
} else if (plat->reg_width == 4) {
if (plat->flags & NS16550_FLAG_ENDIAN) {
if (plat->flags & NS16550_FLAG_BE)
out_be32(addr, value);
else
out_le32(addr, value);
} else {
writel(value, addr);
}
} else if (plat->flags & NS16550_FLAG_BE) {
writeb(value, addr + (1 << plat->reg_shift) - 1);
} else {
writeb(value, addr);
}
}
static int serial_in_dynamic(struct ns16550_platdata *plat, u8 *addr)
{
if (plat->flags & NS16550_FLAG_IO) {
return inb(addr);
} else if (plat->reg_width == 4) {
if (plat->flags & NS16550_FLAG_ENDIAN) {
if (plat->flags & NS16550_FLAG_BE)
return in_be32(addr);
else
return in_le32(addr);
} else {
return readl(addr);
}
} else if (plat->flags & NS16550_FLAG_BE) {
return readb(addr + (1 << plat->reg_shift) - 1);
} else {
return readb(addr);
}
}
#else
static inline void serial_out_dynamic(struct ns16550_platdata *plat, u8 *addr,
int value)
{
}
static inline int serial_in_dynamic(struct ns16550_platdata *plat, u8 *addr)
{
return 0;
}
#endif /* CONFIG_NS16550_DYNAMIC */
static void ns16550_writeb(NS16550_t port, int offset, int value)
{
struct ns16550_platdata *plat = port->plat;
unsigned char *addr;
offset *= 1 << plat->reg_shift;
addr = (unsigned char *)plat->base + offset;
addr = (unsigned char *)plat->base + offset + plat->reg_offset;
/*
* As far as we know it doesn't make sense to support selection of
* these options at run-time, so use the existing CONFIG options.
*/
serial_out_shift(addr + plat->reg_offset, plat->reg_shift, value);
if (IS_ENABLED(CONFIG_NS16550_DYNAMIC))
serial_out_dynamic(plat, addr, value);
else
serial_out_shift(addr, plat->reg_shift, value);
}
static int ns16550_readb(NS16550_t port, int offset)
@ -114,9 +174,12 @@ static int ns16550_readb(NS16550_t port, int offset)
unsigned char *addr;
offset *= 1 << plat->reg_shift;
addr = (unsigned char *)plat->base + offset;
addr = (unsigned char *)plat->base + offset + plat->reg_offset;
return serial_in_shift(addr + plat->reg_offset, plat->reg_shift);
if (IS_ENABLED(CONFIG_NS16550_DYNAMIC))
return serial_in_dynamic(plat, addr);
else
return serial_in_shift(addr, plat->reg_shift);
}
static u32 ns16550_getfcr(NS16550_t port)

16
include/ns16550.h
View File

@ -31,6 +31,9 @@
#define CONFIG_SYS_NS16550_REG_SIZE (-1)
#endif
#ifdef CONFIG_NS16550_DYNAMIC
#define UART_REG(x) unsigned char x
#else
#if !defined(CONFIG_SYS_NS16550_REG_SIZE) || (CONFIG_SYS_NS16550_REG_SIZE == 0)
#error "Please define NS16550 registers size."
#elif defined(CONFIG_SYS_NS16550_MEM32) && !defined(CONFIG_DM_SERIAL)
@ -44,14 +47,24 @@
unsigned char x; \
unsigned char postpad_##x[-CONFIG_SYS_NS16550_REG_SIZE - 1];
#endif
#endif /* CONFIG_NS16550_DYNAMIC */
enum ns16550_flags {
NS16550_FLAG_IO = 1 << 0, /* Use I/O access (else mem-mapped) */
NS16550_FLAG_ENDIAN = 1 << 1, /* Use out_le/be_32() */
NS16550_FLAG_BE = 1 << 2, /* Big-endian access (else little) */
};
/**
* struct ns16550_platdata - information about a NS16550 port
*
* @base: Base register address
* @reg_width: IO accesses size of registers (in bytes)
* @reg_width: IO accesses size of registers (in bytes, 1 or 4)
* @reg_shift: Shift size of registers (0=byte, 1=16bit, 2=32bit...)
* @reg_offset: Offset to start of registers (normally 0)
* @clock: UART base clock speed in Hz
* @fcr: Offset of FCR register (normally UART_FCR_DEFVAL)
* @flags: A few flags (enum ns16550_flags)
* @bdf: PCI slot/function (pci_dev_t)
*/
struct ns16550_platdata {
@ -61,6 +74,7 @@ struct ns16550_platdata {
int reg_offset;
int clock;
u32 fcr;
int flags;
#if defined(CONFIG_PCI) && defined(CONFIG_SPL)
int bdf;
#endif