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 ---
Changes in v3: - Rewrite the conditional logic to a fix a bug and match serial_xx_shift() - Add a separate flag for whether to use endian-aware out() functions
Changes in v2: - runtime -> run-time - Enable run-time config for slimbootloader too - Improve Kconfig help based on Bin's comments - Use ns16550 in patch subject
drivers/serial/Kconfig | 21 ++++++++++++++ drivers/serial/ns16550.c | 59 ++++++++++++++++++++++++++++++++++------ include/ns16550.h | 16 ++++++++++- 3 files changed, 87 insertions(+), 9 deletions(-)
diff --git a/drivers/serial/Kconfig b/drivers/serial/Kconfig index ece7d87d4c..472a9f0929 100644 --- a/drivers/serial/Kconfig +++ b/drivers/serial/Kconfig @@ -598,6 +598,27 @@ 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 diff --git a/drivers/serial/ns16550.c b/drivers/serial/ns16550.c index 754b6e9921..eacca5b703 100644 --- a/drivers/serial/ns16550.c +++ b/drivers/serial/ns16550.c @@ -92,19 +92,59 @@ static inline int serial_in_shift(void *addr, int shift) #define CONFIG_SYS_NS16550_CLK 0 #endif
+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); + } +} + 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) @@ -113,9 +153,12 @@ 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) diff --git a/include/ns16550.h b/include/ns16550.h index 701efeea85..18c9077755 100644 --- a/include/ns16550.h +++ b/include/ns16550.h @@ -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