This commit removes an endless loop, that occurred when the sd_card driver
called usleep, or msleep on its Timer_delayer object. Fixes#705
Also fixes the same problem for the Omap4 GPIO driver.
This patch simplifies the way of how Genode's base libraries are
organized. Originally, the base API was implemented in the form of many
small libraries such as 'thread', 'env', 'server', etc. Most of them
used to consist of only a small number of files. Because those libraries
are incorporated in any build, the checking of their inter-dependencies
made the build process more verbose than desired. Also, the number of
libraries and their roles (core only, non-core only, shared by both core
and non-core) were not easy to capture.
Hereby, the base libraries have been reduced to the following few
libraries:
- startup.mk contains the startup code for normal Genode processes.
On some platform, core is able to use the library as well.
- base-common.mk contains the parts of the base library that are
identical by core and non-core processes.
- base.mk contains the complete base API implementation for non-core
processes
Consequently, the 'LIBS' declaration in 'target.mk' files becomes
simpler as well. In the most simple case, only the 'base' library must
be mentioned.
Fixes#18
With this patch, the driver code gets complemented with DMA support.
The support for master DMA, in turn, cleared the way for using
interrupts to wait for the completion of transfers, which largely
relieves the CPU compared to the polling PIO mode. Consequently, the new
version has a much lower CPU footprint.
In the current version, both modes of operation PIO and DMA are
functional. However, PIO mode is retained for benchmarking purposes only
and will possibly be removed to keep the driver simple. It is disabled
in the driver's 'main.cc'.
This patch replaces the jiffies thread in 'sd_card/omap4/bench' calls to
'Timer::Session::elapsed_ms()'. This way, we use wall-clock time for the
measurements. Depending on the load of the rest of the system, the
previous version used to accumulate the inaccuracy for each 'msleep'
call.
The new SD card driver at 'os/src/drivers/sd_card/omap4' allows the use
of an SD card with the Pandaboard as block service. Currently, the
driver is using PIO, no DMA, and no IRQs. The driver can be tested using
the 'os/run/sd_card.run' script.