Changeset a4bd537 in mainline for kernel/genarch/src/drivers/pl011/pl011.c

Timestamp:

2019-04-06T13:39:58Z (5 years ago)

Author:

Petr Pavlu <setup@…>

Children:

f7842ef

Parents:

0d073b8

git-author:

Petr Pavlu <setup@…> (2019-03-31 14:09:57)

git-committer:

Petr Pavlu <setup@…> (2019-04-06 13:39:58)

Message:

arm64: Add support for the architecture

This changeset adds basic support to run HelenOS on AArch64, targeting
the QEMU virt platform.

Boot:

• Boot relies on the EDK II firmware, GRUB2 for EFI and the HelenOS bootloader (UEFI application). EDK II loads GRUB2 from a CD, GRUB2 loads the HelenOS bootloader (via UEFI) which loads OS components.
• UEFI applications use the PE/COFF format and must be relocatable. The first problem is solved by manually having the PE/COFF headers and tables written in assembler. The relocatable requirement is addressed by compiling the code with -fpic and having the bootloader relocate itself at its startup.

Kernel:

• Kernel code for AArch64 consists mostly of stubbing out various architecture-specific hooks: virtual memory management, interrupt and exception handling, context switching (including FPU lazy switching), support for virtual timer, atomic sequences and barriers, cache and TLB maintenance, thread and process initialization.
• The patch adds a kernel driver for GICv2 (interrupt controller).
• The PL011 kernel driver is extended to allow userspace to take ownership of the console.
• The current code is not able to dynamically obtain information about available devices on the underlying machine. The port instead implements a machine-func interface similar to the one implemented by arm32. It defines a machine for the QEMU AArch64 virt platform. The configuration (device addresses and IRQ numbers) is then baked into the machine definition.

User space:

• Uspace code for AArch64 similarly mostly implements architecture-specific hooks: context saving/restoring, syscall support, TLS support.

The patchset allows to boot the system but user interaction with the OS
is not yet possible.

File:

• kernel/genarch/src/drivers/pl011/pl011.c (modified) (3 diffs)

kernel/genarch/src/drivers/pl011/pl011.c

@@ -60 +60 @@
         pl011_uart_t *uart = dev->data;
 
-        if (!ascii_check(ch)) {
+        /* If the userspace owns the console, do not output anything. */
+        if (uart->parea.mapped && !console_override)
+                return;
+
+        if (!ascii_check(ch))
                 pl011_uart_sendb(uart, U_SPECIAL);
-        } else {
+        else {
                 if (ch == '\n')
                         pl011_uart_sendb(uart, (uint8_t) '\r');
@@ -100 +104 @@
         assert(uart);
         uart->regs = (void *)km_map(addr, sizeof(pl011_uart_regs_t),
-            KM_NATURAL_ALIGNMENT, PAGE_NOT_CACHEABLE);
+            KM_NATURAL_ALIGNMENT, PAGE_WRITE | PAGE_NOT_CACHEABLE);
         assert(uart->regs);
 
@@ -131 +135 @@
         uart->irq.instance = uart;
 
+        ddi_parea_init(&uart->parea);
+        uart->parea.pbase = addr;
+        uart->parea.frames = 1;
+        uart->parea.unpriv = false;
+        uart->parea.mapped = false;
+        ddi_parea_register(&uart->parea);
+
         return true;
 }