From 890134dc8238cdd92507e831eed2418f7e720293 Mon Sep 17 00:00:00 2001
From: Stefan Lankes <slankes@eonerc.rwth-aachen.de>
Date: Sun, 5 Mar 2017 18:48:51 +0100
Subject: [PATCH] simplify uart device
- HermitCore uses on uart to send log messages to qemu
- unidirectional communication => remove interrupt handler
- remove mmio support for uart
---
arch/x86/include/asm/uart.h | 6 --
arch/x86/kernel/uart.c | 150 ++----------------------------------
kernel/main.c | 1 -
libkern/stdio.c | 2 +-
4 files changed, 8 insertions(+), 151 deletions(-)
diff --git a/arch/x86/include/asm/uart.h b/arch/x86/include/asm/uart.h
index 3514c30a2..f849fabeb 100644
--- a/arch/x86/include/asm/uart.h
+++ b/arch/x86/include/asm/uart.h
@@ -40,12 +40,6 @@ extern "C" {
*/
int uart_init(void);
-/** @brief Initialize UART output without a device check
- *
- * @return Returns 0 on success
- */
-int uart_early_init(char*);
-
/** @brief Simple string output on a serial device.
*
* If you want a new line you will have to "\\n".
diff --git a/arch/x86/kernel/uart.c b/arch/x86/kernel/uart.c
index 9dc9c1698..7a8a94044 100644
--- a/arch/x86/kernel/uart.c
+++ b/arch/x86/kernel/uart.c
@@ -97,40 +97,28 @@
#define UART_MCR_RTS 0x02 /* RTS complement */
#define UART_MCR_DTR 0x01 /* DTR complement */
-static uint8_t mmio = 0;
static size_t iobase = 0;
static inline unsigned char read_from_uart(uint32_t off)
{
uint8_t c = 0;
- if (mmio)
- c = *((const volatile unsigned char*) (iobase + off));
- else if (iobase)
+ if (iobase)
c = inportb(iobase + off);
return c;
}
-static void write_to_uart(uint32_t off, unsigned char c)
+static inline void write_to_uart(uint32_t off, unsigned char c)
{
- if (mmio)
- *((volatile unsigned char*) (iobase + off)) = c;
- else if (iobase)
+ if (iobase)
outportb(iobase + off, c);
}
-
-/* Get a single character on a serial device */
-static unsigned char uart_getchar(void)
-{
- return read_from_uart(UART_RX);
-}
-
/* Puts a single character on a serial device */
int uart_putchar(unsigned char c)
{
- if (!iobase && !mmio)
+ if (!iobase)
return 0;
write_to_uart(UART_TX, c);
@@ -143,7 +131,7 @@ int uart_puts(const char *text)
{
size_t i, len = strlen(text);
- if (!iobase && !mmio)
+ if (!iobase)
return 0;
for (i = 0; i < len; i++)
@@ -152,39 +140,6 @@ int uart_puts(const char *text)
return len;
}
-/* Handles all UART's interrupt */
-static void uart_handler(struct state *s)
-{
- unsigned char c = read_from_uart(UART_IIR);
-
- while (!(c & UART_IIR_NO_INT)) {
- if (c & UART_IIR_RDI) {
- c = uart_getchar();
-
- //TODO: handle input messages
-
- goto out;
- }
-
- if(c & UART_IIR_THRI) {
- // acknowledge interrupt
- c = read_from_uart(UART_IIR);
-
- goto out;
- }
-
- if(c & UART_IIR_RLSI) {
- // acknowledge interrupt
- c = read_from_uart(UART_LSR);
-
- goto out;
- }
-
-out:
- c = read_from_uart(UART_IIR);
- }
-}
-
static int uart_config(void)
{
/*
@@ -226,105 +181,14 @@ static int uart_config(void)
extern const void kernel_start;
-int uart_early_init(char* cmdline)
-{
- if (is_uhyve())
- return 0;
-#if 1
- // default value of our QEMU configuration
- iobase = 0xc110;
-#else
- if (BUILTIN_EXPECT(!cmdline, 0))
- return -EINVAL;
-
- char* str = strstr(cmdline, "uart=");
- if (!str)
- return -EINVAL;
-
- if (strncmp(str, "uart=io:", 8) == 0) {
- iobase = strtol(str+8, (char **)NULL, 16);
- if (!iobase)
- return -EINVAL;
- mmio = 0;
- } else if (strncmp(str, "uart=mmio:", 10) == 0) {
- iobase = strtol(str+10, (char **)NULL, 16);
- if (!iobase)
- return -EINVAL;
- if (iobase >= PAGE_MAP_ENTRIES*PAGE_SIZE) {
- /* at this point we use the boot page table
- * => IO address is not mapped
- * => dirty hack, map device before the kernel
- */
- int err;
- size_t newaddr = ((size_t) &kernel_start - PAGE_SIZE);
-
- err = page_map_bootmap(newaddr & PAGE_MASK, iobase & PAGE_MASK, PG_GLOBAL | PG_ACCESSED | PG_DIRTY | PG_RW | PG_PCD);
- if (BUILTIN_EXPECT(err, 0)) {
- iobase = 0;
- return err;
- }
- iobase = newaddr;
- }
- mmio = 1;
- }
-#endif
-
- // configure uart
- return uart_config();
-}
-
int uart_init(void)
{
if (is_uhyve())
return 0;
-#ifdef CONFIG_PCI
- pci_info_t pci_info;
- uint32_t bar = 0;
-
- // Searching for Intel's UART device
- if (pci_get_device_info(0x8086, 0x0936, iobase, &pci_info) == 0)
- goto Lsuccess;
- // Searching for Qemu's UART device
- if (pci_get_device_info(0x1b36, 0x0002, iobase, &pci_info) == 0)
- goto Lsuccess;
- // Searching for Qemu's 2x UART device (pci-serial-2x)
- if (pci_get_device_info(0x1b36, 0x0003, iobase, &pci_info) == 0)
- goto Lsuccess;
- // Searching for Qemu's 4x UART device (pci-serial-4x)
- if (pci_get_device_info(0x1b36, 0x0004, iobase, &pci_info) == 0)
- goto Lsuccess;
-
- return -1;
-
-Lsuccess:
- iobase = pci_info.base[bar];
- irq_install_handler(32+pci_info.irq, uart_handler);
- if (pci_info.type[0]) {
- mmio = 0;
- LOG_INFO("UART uses io address 0x%x\n", iobase);
- } else {
- mmio = 1;
- page_map(iobase & PAGE_MASK, iobase & PAGE_MASK, 1, PG_GLOBAL | PG_ACCESSED | PG_DIRTY | PG_RW | PG_PCD);
- LOG_INFO("UART uses mmio address 0x%x\n", iobase);
- vma_add(iobase, iobase + PAGE_SIZE, VMA_READ|VMA_WRITE);
- }
+ // default value of our QEMU configuration
+ iobase = 0xc110;
// configure uart
return uart_config();
-#else
- // per default we use COM1...
- if (!iobase)
- iobase = 0x3F8;
- mmio = 0;
- if ((iobase == 0x3F8) || (iobase == 0x3E8))
- irq_install_handler(32+4, uart_handler);
- else if ((iobase == 0x2F8) || (iobase == 0x2E8))
- irq_install_handler(32+3, uart_handler);
- else
- return -EINVAL;
-
- // configure uart
- return uart_config();
-#endif
}
diff --git a/kernel/main.c b/kernel/main.c
index 2eda4d3a8..bbd6d00d9 100644
--- a/kernel/main.c
+++ b/kernel/main.c
@@ -132,7 +132,6 @@ static int hermit_init(void)
multitasking_init();
memory_init();
signal_init();
- uart_init();
return 0;
}
diff --git a/libkern/stdio.c b/libkern/stdio.c
index ed53c1885..0b1976589 100644
--- a/libkern/stdio.c
+++ b/libkern/stdio.c
@@ -45,7 +45,7 @@ spinlock_irqsave_t stdio_lock = SPINLOCK_IRQSAVE_INIT;
int koutput_init(void)
{
if (is_single_kernel())
- uart_early_init(NULL);
+ uart_init();
return 0;
}