Commit Graph

71 Commits

Author SHA1 Message Date
Michael LeMay
52d75dce0d x86: Remove spurious UEFI-related info message
This patch removes a spurious info message in a UEFI-related portion
of a Makefile.
2015-12-21 08:06:14 -02:00
Michael LeMay
0e99ebbded x86: Add support for 32-bit build hosts in build_uefi.sh
This patch adds support for building the UEFI EDK2 tools on 32-bit
hosts.  It also revises the script to support rebuilding the tools
when the script is re-invoked after the EDK2 repository has previously
been downloaded.
2015-12-21 08:06:14 -02:00
Michael LeMay
e297177a69 x86: Streamline MMIO accesses in GPIO and I2C drivers
This patch refactors the MMIO routines in the GPIO and I2C drivers to
eliminate the base_addr parameter that specifies the MMIO base
address.  Instead, just the MMIO routines themselves retrieve the base
address from the driver structure.
2015-12-21 08:06:14 -02:00
Michael LeMay
f85654a82f x86, galileo: Add UEFI support
This patch adds support for optionally building EFI binaries in
addition to Multiboot ELF binaries.  It includes a script,
build_uefi.sh, that downloads tool and library sources from the EDK II
project, builds the GenFw tool that is used to create UEFI binaries,
and creates a makefile that is included from the main x86 common
makefile and enables UEFI support in the Contiki build system.  If the
script is not run prior to building Contiki, then an informational
message will be displayed with instructions for running build_uefi.sh
if UEFI support is desired.  This patch also adds the path to the
auto-generated makefile to .gitignore.

This patch modifies the linker script for the Intel Quark X1000 to
account for the output file section offsets and alignment expectations
of the EDK II GenFw project.

This patch also adds a newlib patch to remove the weak symbol
attribute from floating point stdio support routines.  See
<newlib>/newlib/README for an explanation of how the newlib developers
intended for _printf_float and _scanf_float to be linked.  Newlib
declares them as weak symbols with the intention that developers would
force them to be linked only when needed using a linker command line
option.  However, some but not all Contiki programs require them, so
we cannot simply always include or exclude them.  Instead, we remove
the weak symbol attributes and rely on the linker to automatically
determine whether or not they should be linked.  This avoids an issue
in which weak symbols were undefined in the intermediate DLL generated
as part of the UEFI build process.  That resulted in the GenFw program
emitting "ERROR 3000" messages when it encountered relocations
referencing such an undefined symbol.

Finally, this patch updates README.md to both make some revisions to
account for the UART support introduced in previous patches as well as
to provide instructions for using the UEFI support.
2015-12-21 08:06:14 -02:00
Michael LeMay
b915e7d5e3 galileo: Omit exception handling unwind tables
This patch modifies the newlib and Contiki C and C++ compiler flags to
omit exception handling unwind tables (see
http://wiki.dwarfstd.org/index.php?title=Exception_Handling).
Removing these tables saves space in debug builds and has not caused
any readily-apparent functional changes.

Here is the size listing for an example program built without this
patch:
   text	   data	    bss	    dec	    hex	filename
  76002	   1508	  21224	  98734	  181ae	all-timers.galileo

Here is the size listing for the same program with this patch:
   text	   data	    bss	    dec	    hex	filename
  72918	   1508	  21224	  95650	  175a2	all-timers.galileo

The primary motivation for this patch is to help enable UEFI support.
The .eh_frame and .eh_frame_hdr sections that are otherwise generated
are treated as code sections by the EDK2 GenFw program, since they are
read-only alloc sections.  They get grouped with the actual code
sections, ahead of the data sections.  This perturbs symbols and
complicates debugging.
2015-12-21 08:06:14 -02:00
Michael LeMay
abeed93da5 x86: Add driver for Intel Quark X1000 built-in Ethernet
This patch adds a simple, space-efficient driver for the Ethernet
interface built into the Intel Quark X1000.  It only allocates a
single packet descriptor for each of the transmit and receive
directions, computes checksums on the CPU, and enables
store-and-forward mode for both transmit and receive directions.
2015-12-21 08:06:14 -02:00
Ricardo de Almeida Gonzaga
4726bc3313 x86: Add Intel Quark X1000 GPIO Controller (non-legacy) interrupt support
Since Galileo pinmux is available, this patch adds interrupt support
for GPIO Controller (non-legacy).
2015-12-21 08:06:14 -02:00
Ricardo de Almeida Gonzaga
495dcd659a x86: Add PCAL9535A support
This patch adds gpio-pcal9535a.c and gpio-pcal9535a.h files,
which support access to I2C-based PCAL9535A GPIO controller
configuration register through a function interface.

The PCAL9535A is a low-voltage 16-bit GPIO expander with interrupt
and reset for I2C-bus/SMBus applications. It contains the PCA9535
register set of four pairs of 8-bit Configuration, Input, Output,
and Polarity Inversion registers, and additionally, the PCAL9535A has
Agile I/O, which are additional features specifically designed to
enhance the I/O. More about PCAL9535A can be found in its datasheet[1].

This driver is needed in order to configure Galileo pinmux.

[1] - http://www.nxp.com/documents/data_sheet/PCAL9535A.pdf
2015-12-21 08:06:14 -02:00
Ricardo de Almeida Gonzaga
a27af5b395 x86: Add Intel Quark X1000 I2C support
This patch adds the i2c.c, i2c.h and i2c-registers.h files,
which support access to I2C controller configuration register
through a function interface.
2015-12-21 08:06:14 -02:00
Ricardo de Almeida Gonzaga
2d552285cd x86: Add Intel Quark X1000 GPIO Controller (non-legacy) support
This patch adds the gpio.c and gpio.h files, which support
access to GPIO Controller (non-legacy) configuration register
through a function interface.

It doesn't add interrupt support due to pinmux reasons. On
Galileo Gen 2 we need to configure a pin as input/interrupt
using pinmux and this can only be achieved through I2C. There's
one pin exported by default as GPIO output and we used this one
to test this driver.

In the future, we plan to add an I2C driver and a pinmux configuration
driver in order to solve this kind of problems.
2015-12-21 08:06:14 -02:00
Ricardo de Almeida Gonzaga
60f6edef80 x86: Add support for PCI BAR1
This patch adds support for PCI BAR1 and also changes
the pci_init(), instead of having one function for each `bar`
we now set the `bar` to pci_config_addr_t parameter before calling
the pci_init() function..
2015-12-21 08:06:14 -02:00
Michael LeMay
6dc27579bc x86: Extend PCI driver module with support for metadata and configuration writes
This patch adds the 'meta' field to the generic driver structure to
point to optional driver-defined metadata.  It also modifies the
associated initialization routine to populate it and updates the 16X50
UART driver to use the new initialization routine signature.  This
patch also adds a function to perform PCI configuration register
writes, definitions for the PCI Command configuration register address
and some of the bits in that register, and a function to set
additional bits in that register.  Finally, it adds macros to help
with performing MMIO to and from PCI devices.
2015-12-21 08:06:14 -02:00
Andre Guedes
c6ef8454a1 x86: Use -O0 instead of -Og for debug build
This patch replaces the gcc option '-Og' by '-O0' which is used when
building debugging binaries. The motivation for this change comes
from the fact that we have found at least one optimization done by
'-Og' that interfered with one of our debugging sessions.
2015-12-21 08:06:14 -02:00
Andre Guedes
6b433aede1 x86: Improve release binary size
This patch adds -ffunction-sections and -fdata-sections to the
'release' CFLAGS so each function and data is place into its
own section in the output file. It also adds --gc-section to
the 'release' LDFLAGS so the linker removes the sections which
are not referenced.

This patch also adds -ffunction-sections and -fdata-sections
options to CFLAGS from build_newlib.sh. This increases newlib
static libraries size, however, the Contiki image shrinks even
more since --gc-section removes "dead code" from newlib.

As a practical effect, all unused function and data (as well as
sections such as .eh_frame) are striped out from the final elf
binary. This shrinks our release binary drastically.

Finally, to prevent --gc-section from removing .multiboot section,
this patch adds KEEP(*(.multiboot)) to quarkX1000.ld.
2015-12-21 08:06:14 -02:00
Ricardo de Almeida Gonzaga
c796e270bf x86: Add Intel Quark X1000 PCI Interrupt Routing support
PCI Interrupt Routing is mapped using Interrupt Queue Agents
IRQAGENT[0:3] and aggregating the INT[A:D] interrupts for each
PCI-mapped device in the SoC.

PCI based interrupts PIRQ[A:H] are then available for consumption
by either the 8259 PICs or the IO-APIC, depending on the configuration
of the 8 PIRQx Routing Control Registers PIRQ[A:H].

More information about can be find in Intel Quark X1000 datasheet[1]
section 21.11.

[1] - http://www.intel.com/content/www/us/en/embedded/products/quark/quark-x1000-datasheet.html
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia
8ae392e66f x86: Reduce .eh_frame section size
When generating binaries, gcc will always add information of what it
calls "the exception handler framework" into its own section: .eh_frame.
This section is based on the DWARF format's call frame information (CFI) [1]
and holds information that can be useful for debuggers but also for language
constructs that relies on always having stack unwinding information (i.e. exceptions).
Such constructs, however, are pretty much useless for the C language and are
mainly just used on C++. Furthermore, this section is one of the loadable sections
of a binary, meaning it will take extra space on flash.

When .eh_frame is not present, debuggers can still get the exact same information
they need for unwinding a stack frame and for restoring registers thanks to yet
another section: .debug_frame. This section is generated by '-g' gcc option and
friends. It is actually defined by DWARF and, as opposed to .eh_frame, is not a
loadable section. In other words, it is 'strippable' while .eh_frame is not.

Since all we need is the debug information we can get from .debug_frame, we can
disable the generation of these large and unused information tables by using gcc's
'-fno-asynchronous-unwind-tables'. The .eh_frame section stays around but the code
size issue is heavily tackled. This is the same approach taken on other projects
that target small code size generation [2] [3].

Pratically speaking, on a DEBUG build of the all-timers appplication, before this
patch we had:
   text    data     bss     dec     hex filename
  21319    1188   12952   35459    8a83 all-timers.galileo

And now, after this patch:
   text    data     bss     dec     hex filename
  16347    1188   12952   30487    7717 all-timers.galileo

This means a ~5Kb reduction on the loadable text segment (.text + .rodata + .eh_frame).

The flag is applied regardless of build type, DEBUG or RELEASE, since it benefits both.
Note that when release builds apply --gc-sections, they will remove .eh_frame section entirely.

[1] http://comments.gmane.org/gmane.comp.standards.dwarf/222
[2] 0d74ad383b
[3] http://git.musl-libc.org/cgit/musl/commit/?id=b439c051c7eee4eb4b93fc382f993aa6305ce530
[4] https://refspecs.linuxfoundation.org/LSB_3.0.0/LSB-Core-generic/LSB-Core-generic/ehframechpt.html

Signed-off-by: Jesus Sanchez-Palencia <jesus.sanchez-palencia@intel.com>
2015-12-21 08:06:14 -02:00
Michael LeMay
0dcd5e9b5a x86: Revise CFLAGS and LDFLAGS for LLVM Clang compatibility
This patch slightly revises CFLAGS and LDFLAGS to specify the
optimization and debugging options and linker script in a way that is
compatible with using Clang as the C compiler and to invoke the linker
(i.e. CC = clang and LD = clang).
2015-12-21 08:06:14 -02:00
Michael LeMay
128d9f3566 x86: Revise SET_INTERRUPT_HANDLER to avoid using inline assembly feature that does not work with LLVM Clang
The SET_INTERRUPT_HANDLER macro in interrupt.h used an inline assembly
feature to cause GCC to generate a unique number for a trampoline
label.  Clang compiled the code using that feature without generating
any compile-time errors, but it always generated the number 0,
resulting in all interrupt trampolines having the same label names.
This patch replaces the usage of that feature with local labels, which
are supported by both GCC and Clang.  See
https://sourceware.org/binutils/docs/as/Symbol-Names.html for an
explanation of local labels.
2015-12-21 08:06:14 -02:00
Michael LeMay
f9072c166b x86: Add missing clobber list in interrupt.h
The SET_INTERRUPT_HANDLER macro defines and registers an interrupt
handler.  It outputs a trampoline for the interrupt handler using a
block of inline assembly, and the address of that trampoline is what
is actually placed in the IDT.  That trampoline invokes the main body
of the interrupt handler.

This patch adds a missing clobber list to the inline assembly block.
It simply lists the caller-saved registers defined by the cdecl
calling convention: EAX, ECX, and EDX.  This is necessary, because the
inline assembly block invokes idt_set_intr_gate_desc using a call
instruction at the time the function containing the
SET_INTERRUPT_HANDLER instance is executed.  The
idt_set_intr_gate_desc function is free to clobber EAX, ECX, and EDX
according to cdecl.  A Clang-generated implementation of
idt_set_intr_gate_desc did in fact clobber those registers, resulting
in incorrect operation of the code following an instance of
SET_INTERRUPT_HANDLER.  The change in this patch informs the compiler
that those registers may be clobbered so that it can adjust the code
that it outputs around the inline assembly block accordingly.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia
bdcf58033a x86: Group sections for QuarkX1000
Child sections can be created depending on the CFLAGS used when building Contiki.
For instance, if built with -ffunction-sections or -fdata-sections would create
one section per function/variable and -Os sometimes split part of .text into one
child section.

This can also be an issue if we start linking with external libraries that are
built in such a way. Since we can't foresee how the port is going to be used,
we should make sure it is ready for the cases above.

This patch fixes this by correctly grouping child sections into their parent
sections.

Patch developed while investigating a bug with José Souza (jose.souza@intel.com).
2015-12-21 08:06:14 -02:00
Andre Guedes
8a0bc49433 x86: Improve debugging experience
This patch appends some gcc options to CFLAGS when building the default
image in order to improve the debugging experience on GDB.

We use the '-ggdb' option which produces debugging information used by
GDB (including GDB extensions) with level 3 which includes preprocessor
macros information. We also use '-Og' which enables optimizations that
do not interfere with debugging. According to gcc manpage, it should be
the optimization level of choice for the standard edit-compile-debug
cycle, offering a reasonable level of optimization while maintaining
fast compilation and a good debugging experience.

Also, this patch removes the '-g' option from the default CFLAGS because
there is no point in using it when BUILD_RELEASE=1.

As expected, the overall ELF image increases (due to -ggdb3 option) while
the .text section is reduced (due to -Og). For the sake of comparison,
below follows the output of 'size'.

Before patch:
$ size -A hello-world.galileo
hello-world.galileo  :
section           size      addr
.text            13766   1048576
.rodata            241   1064960
.eh_frame         5160   1065204
.eh_frame_hdr     1212   1070364
.data             1188   1073152
.bss             12808   1077248
.debug_info      14351         0
.debug_abbrev     6281         0
.debug_aranges     768         0
.debug_line       6443         0
.debug_str        4805         0
.comment            17         0
.note               40         0
.debug_ranges       24         0
Total            67104

After patch:
$ size -A hello-world.galileo
hello-world.galileo  :
section            size      addr
.text             11718   1048576
.rodata             249   1060864
.eh_frame          5496   1061116
.eh_frame_hdr      1204   1066612
.data              1156   1069056
.bss              12808   1073152
.debug_info       16727         0
.debug_abbrev      7254         0
.debug_loc         2083         0
.debug_aranges      768         0
.debug_macro      17273         0
.debug_line       13433         0
.debug_str        42192         0
.comment             17         0
.note                40         0
Total            132418
2015-12-21 08:06:14 -02:00
Andre Guedes
c9020d95e7 x86: Build release image
This patch adds support for building release images. The main difference
between release images and default images is that the former is optimized
for size while the latter is "optimized" for debugging. To build a release
image, the BUILD_RELEASE variable should be set to 1. For instance, the
following command build a release image from the hello-world application:
$ cd examples/hello-world && make TARGET=galileo BUILD_RELEASE=1

To optimize for size we use the '-Os' option from gcc. This option also
enables the strict aliasing optimization. This generates lots of warning
messages since we use the '-Wall' option and lots of code in core/net/
break the strict-aliasing rules. Some test have shown that the strict
aliasing optimization it not taking effect in the final binary. For that
reasons, this patch manually disables the optimization. Also, the release
image is stripped.

For the sake of comparison, below follows the output from 'wc' and 'size'
for both debugging (default) and release images.

Default image:
$  wc -c hello-world.galileo
71112 hello-world.galileo
$ size hello-world.galileo
   text    data     bss     dec     hex filename
  20379    1188   12808   34375    8647 hello-world.galileo

Release image:
$ wc -c hello-world.galileo
26320 hello-world.galileo
$ size hello-world.galileo
   text    data     bss     dec     hex filename
  18146    1156   12808   32110    7d6e hello-world.galileo
2015-12-21 08:06:14 -02:00
Michael LeMay
15f947fe40 x86: Add Intel Quark X1000 UART support.
This patch adds a driver that wraps the generic 16X50 UART driver with
specific support for the two Intel Quark X1000 built-in UARTs.
2015-12-21 08:06:14 -02:00
Michael LeMay
6acdf50262 x86: Add driver for MMIO-accessible 16X50 UART
This patch adds a driver for an MMIO-accessible 16X50 UART.  It
assumes that the boot firmware assigned an MMIO range to the UART.  It
operates in polled mode with FIFOs enabled.
2015-12-21 08:06:14 -02:00
Michael LeMay
c5f9cefac7 x86: Add generic driver structure and associated initialization code
This patch adds a generic device driver structure with a field for
referencing an MMIO range.  It also provides a structure
initialization procedure that initializes the MMIO range field with
the value read from the PCI BAR0 register for a device.
2015-12-21 08:06:14 -02:00
Michael LeMay
2dccb55e15 x86: Add PCI support
This patch adds the pci.c and pci.h files, which support access to PCI
configuration registers through a function interface.  It defines the
PCI configuration register access I/O port addresses and the
pci_config_addr union and structure to assist in specifying addresses
of PCI configuration registers.  It also defines the PCI configuration
register identifier for PCI BAR0.

This patch also adds wrappers for 32-bit 'in' and 'out' port I/O
instructions.  They were placed in helpers.S, since they may be useful
to other modules besides just the PCI support module.
2015-12-21 08:06:14 -02:00
Michael LeMay
62fc195d0f x86: Refactor GDT initialization code
This patch refactors the GDT initialization code in more of a
self-documenting style.
2015-12-21 08:06:14 -02:00
Andre Guedes
96e50ec2c4 galileo: Fix Makefile.galileo
This patch moves the compiler and linking options related to QuarkX1000
SoC to Makefile.x86_quarkX1000 since it is more suitable. For instance,
'-m32' should be used in any platform based on QuarkX1000, not only
Galileo. The same rationale applies for the others options (e.g. -march,
mtune).
2015-12-21 08:06:14 -02:00
Andre Guedes
b697646b11 x86: Cleanup Makefile.x86_common
This patch does several cleanups in Makefile.x86_common file. The
changes are described above.

1) The CFLAGNO variable was removed since it is used only to assign
   the CFLAGS variable. Also, CFLAGNO is not used outside Makefile.x86_
   common.

2) The "-I/usr/local/include" option was removed since we provide manually
   the include path from newlib in the bsp/ directory.

3) We only support building x86-based platforms on Linux so there is no
   point in setting LDFLAGS conditionally.

4) The '-export-dynamic' option was removed from LDFLAGS since we are not
    creating a dynamically linked executable.

5) Makefile.x86_quarkX1000 is the only one that includes Makefile.x86_
   common. Since it doesn't use the custom rules from Makefile.x86_
   common we remove them.
2015-12-21 08:06:14 -02:00
Andre Guedes
13bbe8a5b5 x86: Don't generate .note.gnu.build-id section
This patch adds "--build-id=none" to default LDFLAGS so
.note.gnu.build-id section is not generated. This section
contains unique identification for the built files what is
not important to us (at least at this moment).

This change simplifies all linker scripts for SoCs based on x86
(at this moment we only have Quark X1000) since we don't have to
care about it anymore.
2015-12-21 08:06:14 -02:00
Andre Guedes
cb0510ebcf x86: Disable NMI while initializing RTC
According to [1], we should disable non-maskable and maskable interrupts
while initializing RTC. Otherwise, the RTC may be left in an undefined
state (non-functional) if an interrupt occurs. Currently, maskable
interrupts are already disabled, but NMI is not.

This patch adds helpers APIs to enable/disable non-maskable interrupts
(NMI) and changes rtc_init() to disable NMI while initializing the RTC.

NMI enable/disable code is legacy-PC specific therefore it was put in
driver/legacy_pc/ directory.

Regarding the RTC initialization changes, just calling nmi_disable() and
nmi_enable is not enough since NMI and RTC share the same IO port. So We
should also set the NMI_ENABLE bit while selecting the RTC_INDEX.

Additionally, the nmi_disable() call is not strictly required since we
set the NMI_ENABLE bit while selecting the RTC_INDEX. However, to make
clear hat we are disabling NMI and to improve readability (by matching
NMI disable/enable), the nmi_disable() call was purposely used.

[1] http://wiki.osdev.org/RTC
2015-12-21 08:06:14 -02:00
Andre Guedes
a8849b2909 x86: Move bootstrap code and linker script to cpu/x86
This is a refactoring patch, no functionality is changed. It moves
loader.S and galileo.ld from platform/galileo/ to cpu/x86/ directory
since they seem to be more SoC-specific than platform-specific.

It also renames galileo.ld to quarkX1000.ld since it can be used by
any platform based on Quark X1000 SoC, not only Galileo.

Furthermore, this patch also renames loader.S to bootstrap_quarkX1000.S
since it is pretty much a bootstrap code to any platform based on Quark
X1000 SoC.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia
80fe1de0b1 x86: Isolate SoC specific cpu_init code
This commit turns cpu_init() into a SoC-agnostic function by
removing any SoC specific calls and isolating them into their
own SoC implementation.

We start this by isolating all IRQs initialization code from
the legacy-pc target, pic_init() and spurious IRQ7 registration,
into a new interface: irq_init() from irq.h. Future SoCs will have
to provide their own implementation of this interface.

This model is to be followed by future initialization code that
we may need to add and which is not common to all x86 SoCs.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia
e4bc1a1e8c x86: Add init folder and move code accordingly
The x86/init/common/ folder holds all cpu initialization
code - idt and gdt setup, interrupts and cpu initialization.

On this folder will also sit any SoC specific implementation of
the functions called from cpu_init().
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia
b2fa72bb98 x86: Break Makefile.x86 into common and pc specific ones
Now the cpu/x86/ provides a Makefile.x86_common and a
Makefile.x86_pc. The former includes the common Makefile
and adds legacy pc specific implementations (currently,
drivers only) into the building context, while the latter
has everything that defines the bootstrap of a x86 CPU.

This commit also fixes platform/galileo/ so it includes the
correct makefile - Makefile.x86_quarkX1000. Galileo uses
a Quark X1000 SoC which is not an IBM Generic PC-like CPU,
but it does provide most of a PCs peripherals through
its "Legacy Bridge". Thus, it makes sense that QuarkX1000's
Makefile includes code from the legacy_pc x86 cpu.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia
23e8090257 x86: Move available drivers into drivers/legacy_pc/
All drivers implemented so far are for chips which are only available
on legacy x86 PCs. This commit moves them into a more appropriate folder,
also making the cpu/x86/drivers/ folder ready for other x86 based SoCs.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia
9d3b9cadc4 galileo: Concentrate core implementations in platform/galileo/core/
Currently, it is common to see Contiki's core/ interfaces implementations
spread in both cpu/ and platform/. We here take one step further starting
an effort to centralize all of these in platform's code instead.

This commit starts this by adding platform/galileo/core/ and its sys/
subfolder, adding a stubbed mtarch.h and moving clock and rtimer
implementations to this new folder. From now on we should concentrate
implementation from Contiki's core/ interfaces into the appropriate
subfolder in platform/galileo/core/.

Note that this is not the current fashion followed on other platforms
and cpus folders, as most of them add the core interface implementation
into its subfolder directly. For instance, on CC2538DK,
core/dev/button-sensor.h is implemented in platform/cc2538dk/dev/
directly, while on Galileo it would sit at platform/galileo/core/dev/.
We believe ours is a better approach to organize and escalate a
platform's code base.

We also remove previous x86 mtarch.h and mtarch.c since they weren't used
at all - both native and cooja platforms have their own mtarch
implementations.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia
3b01e04379 x86: Add a fake IRQ7 handler to avoid spurious interrupts
The 8259a PIC has a well known problem of generating flaky
IRQ7 interrupts. The correct solution is to always check
if an IRQ7 interrupt is real or not by probing the PIC's ISR
register. This check is only mandatory if the IRQ7 is actually
being used by the system. More importantly, the handler should
NEVER send and EOI if the interrupt was spurious.

This patch addresses this issue by implementing a fake empty
handler for this IRQ and, as stated, NOT sending the EOI.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia
afd9b5b0b7 x86: Add APIs to 8259 PIC driver
This commit implements pic_eoi(int irq) and a helper macro PIC_INT(irq).
This first checks which PICs should be 'acked' given an IRQ number, while
the macro returns the actual system interrupt number for the IRQ according
to the offset used on the PIC initialization.
2015-12-21 08:06:14 -02:00
Andre Guedes
826ff7cb29 x86: Add pic_unmask_irq() helper
This patch implements the pic_unmask_irq() helper and uses it where
applicable. This function zeros the corresponding bit from the IRQ
number in IMR register.

This patch doesn't implement the pic_mask_irq() helper since it is not
useful at this moment.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia
d70f67cd60 galileo: Add PIT driver
This patch adds a driver for the 8254 Programmable Interrupt Timer (PIT).
The driver introduced by this patch programs the PIT to generate interrupt
periodically. The interrupt frequency can be configured by the user.

On each PIT interrupt, a callback configured by the user is called. As
expected, that callback is executed in interrupt context so the user
should be aware of what it is not supposed to do (e.g. to call blocking
functions).

Issues marked as FIXME are all related to missing APIs on the PIC driver
so they will be addressed by a future commit.
2015-12-21 08:06:14 -02:00
Andre Guedes
5f47bafc6a x86: Add Real-Time Clock Driver
This patch adds a driver for Real-Time Clock (RTC). The RTC timer is
suitable to implement some operating system features such as the
system clock. Actually, the RTC will be used to implement the system
clock in galileo platform.

The driver introduced by this patch programs the RTC to generate
interrupt periodically. The interrupt frequency can be configured by the
user. On each RTC interrupt, a callback configured by the user is called.
As expected, that callback is executed in interrupt context so the user
should be aware of what it is not supposed to do (e.g. to call blocking
functions).

This patch also adds the inb() helper function to helpers.h. The helpers
is a wrapper for assembly 'in' instruction.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia
11098501d8 x86: Initialize the 8259 PIC
The Programmable Interrupt Controller is a chip responsible for
translating hardware interrupts to system interrupts. When it
receives an Interrupt Request (IRQ), it triggers the appropriate
interrupt line reaching the appropriate IDT gate, following a
previously setup offset.

There are 2 daisy-chained PICs. PIC1 handles IRQs 0-7 and PIC2
handles IRQs 8-15. If no vector offset is set, an IRQ0, for instance,
would trigger the interrupt 0, clashing with the "Division by zero exception"
handler. Thus the IRQs must be remapped.

This patch implements the PICs initialization through their 4
Initialization Command Words (ICWs) in a very "canonical" way:
- ICW1: the initializing command;
- ICW2: the vector offset for the PIC1 and PIC2 (we add an offset of 32 positions);
- ICW3: the inter-PICs wiring setup (we connect PIC2 to PIC1's IRQ2);
- ICW4: extra systems information (we set PIC1 as Master and PIC2 as slave).

It then masks the Interrupt Mask Register, blocking all IRQs but #2 initially.
These must be unmasked on demand. The IMR is 8-bits long, so setting the n^th bit to 1
would DISABLE the IRQ n while setting it to 0 would ENABLE IRQ n.

As stated, this is an implementation of the legacy 8259 PIC. More
investigation is needed so we decide if it is enough or if we need
the (newer) APIC implementation instead.

This patch also adds the outb() helper function to helpers.h. The helpers
is a wrapper for assembly 'out' instruction.

Finally, since we now properly support hardware interrupts, this patch
also enables IRQs in platform main().

More information:
- Quark X1000 Datasheet, section 21.12, page 898.
- http://wiki.osdev.org/8259_PIC
- http://stanislavs.org/helppc/8259.html
2015-12-21 08:06:14 -02:00
Andre Guedes
604538ed62 x86: Set interrupt handler for Double Fault exception
This patch sets an interrupt handler for Double Fault exception during
CPU initialization. In case such exception is raised, we halt the system.
This way, we avoid the system to triple fault (due to an unhandled
interrupt for instance), leaving no trace about what cause the triple
fault.
2015-12-21 08:06:14 -02:00
Andre Guedes
e28f400e0c x86: Introduce interrupt.h
This patch introduces the interrupt.h header file which provides some
helper macros to set a interrupt handler and disable/enable maskable
hardware interrupts.

Since there is no easy way to write an Interrupt Service Routines
(ISR) in C (for further information on this, see [1]), we introduce
the SET_INTERRUPT_HANDLER helper macro.

The macro does two things:
1) Defines an assembly trampolin to a C function that will, indeed,
   handle the interrupt.
2) Sets the corresponding interrupt gate descriptor in IDT.

The macro usage is pretty straightforward. The macro is defined as
SET_INTERRUPT_HANDLER(num, has_error_code, handler) where:
@num:             Interrupt number (0-255)
@has_error_code:  0 if processor doesn't push error code onto the
                  stack. Otherwise, set this argument to 1.
@handler:         Pointer to function that should be called once the
                  interrupt is raised. In case has_error_code == 0
                  the function prototype should be the following:
                  void handler(void)
                  Otherwise, it should be:
                  void handler(struct interrupt_context context)

For instance, let's say we want to set a handler for a device interrupt
(for example, interrupt number 101). Remember, hardware interrupts don't
have error code. So we should have something like this:

void interrupt_handler(void)
{
        /* Handling code here */
}

void my_device_init(void)
{
        ...

        SET_INTERRUPT_HANDLER(101, 0, interrupt_handler);

        ...
}

Now, let's say we want to set an interrupt handler for Page Fault
(interrupt number 14). Some exceptions, such as Page Fault, pushes an
error code onto the stack and may require registers values in order
to be properly be handled. Thus, the code should look like this:

void pagefault_handler(struct interrupt_context context)
{
        /* Handling code here */
}

void init_memory(void)
{
        ...

        SET_INTERRUPT_HANDLER(14, 1, pagefault_handler);

        ...
}

For further information about exceptions and error code, refer to Intel
Combined Manual, Vol. 3, Sections 6.3 and 6.13.

Finally, we don't define any API to unregister interrupt handlers since
we believe that it wouldn't be useful at all, at least at this moment.
Considering Contiki's context, interrupt handler registration is pretty
"static" and defined at compile-time by platform code (or the device
drivers used by the platform).

[1] http://wiki.osdev.org/Interrupt_Service_Routines
2015-12-21 08:06:14 -02:00
Andre Guedes
f6644d9208 x86: CPU Initialization
This patch defines the cpu_init() function which should encapsulate
all code related to x86 CPU initialization. For now, this function
initializes GDT and IDT.
2015-12-21 08:06:14 -02:00
Andre Guedes
13d92cf67a x86: Initialize Interrupt Descriptor Table
This patch adds code to handle Interrupt Descriptor Table (IDT)
initialization. The IDT is initialized with null descriptors
therefore any interrupt at this point will cause a triple fault.
The IDT initialization is part of x86 CPU initialization.

Strictly speaking, there is no need to use attribute packed in struct
intr_gate_desc however we use it for readability reasons.
2015-12-21 08:06:14 -02:00
Andre Guedes
b8feaea30d x86: Add helpers.h
This patch adds the helpers.h. This file should contain only x86-related
helper functions and macros. For now, we define the BIT macro and halt()
helpers which will be used in upcoming patches.

Additionally, this patch also changes loader.S to call the halt().
2015-12-21 08:06:14 -02:00
Andre Guedes
41bca35c1e x86: Initialize Global Descriptor Table
This patch adds code to initialize the Global Descriptor Table. For
simplicity, the memory is organized following the flat model. Thus,
memory appears to Contiki as a single, continuous address space. Code,
data, and stack are all contained in this address space (so called
linear address space).

The macros to manipulate bits from segment descriptor and the
set_descriptor() helper are based on the ones described in [1].

[1] http://wiki.osdev.org/GDT_Tutorial
2015-12-21 08:06:14 -02:00
Andre Guedes
7e13081776 galileo: Print elf sections sizes after build
This patch changes Galileo's buildsystem to print the elf sections
sizes after a new image is built. This way we can easily track how
these sections increase or decrease after any change.

To achieve that, we define a custom linking rule which is pretty much
the same as the default linking rule define in Makefile.include, but
we run 'size' command after the image is built.
2015-12-21 08:06:14 -02:00