The generic parent_cap.cc overwrote the beginning of the data segment with
to much. Reserved are solely 16 byte, for 64bit we use however 32byte.
Actually, the parent_cap copying is not required at all. The parent cap
selector is at a fixed define place, so that no exported symbols are required
for determination of the parent_cap.
Remove it.
By allocating the packet-stream dataspace for block sessions as
uncached, we can use DMA to directly read and write into the client
buffer. Currently, the OMAP4 SD-card driver is using this feature.
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 enable the use of 'Attached_ram_dataspace' objects as DMA buffers,
we need to pass the 'cached' flag to the constructor. By default, the
dataspace is cached, which corresponds to the original behaviour.
Increase size of block session backing store so it can handle maximum supported
packet size. Synchronize client threads during packet allocation.
Fixes#276
The block test at test/ahci is indeed not AHCI-specific. It is a generic
block read/write test for the block-session interface. But in contrast
to the original test/block, it restores the block device content (at
least when the test succeeds). Hence, we remove the original (dangerous)
block test and always use code of test/ahci.
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.
This patch replaces the first attempt to resolve the ambiguity of using
the size_t type that occurred when 'loader_session.h' was included
alongside libc headers. Instead of explicitly qualifying each occurrence
of the type, the new solution defines 'size_t' within the 'Loader' namespace.
Fixes#253
The compiler complained about ambigous references when compiling a
lx_hybrid program using the loader session. Here are some error
messages:
genode/os/include/loader_session/loader_session.h:72: error: reference to 'size_t' is ambiguous
/usr/lib/gcc/i486-linux-gnu/4.4.5/include/stddef.h:211: error: candidates are: typedef unsigned int size_t
genode/base/include/base/stdint.h:25: error: typedef unsigned int Genode::size_t
genode/os/include/loader_session/loader_session.h:72: error: reference to 'size_t' is ambiguous
/usr/lib/gcc/i486-linux-gnu/4.4.5/include/stddef.h:211: error: candidates are: typedef unsigned int size_t
genode/base/include/base/stdint.h:25: error: typedef unsigned int Genode::size_t
...
This commit qualifies size_t using the Genode namespace which fixes
the compilation.
This patch extends the RAM session interface with the ability to
allocate DMA buffers. The client specifies the type of RAM dataspace to
allocate via the new 'cached' argument of the 'Ram_session::alloc()'
function. By default, 'cached' is true, which correponds to the common
case and the original behavior. When setting 'cached' to 'false', core
takes the precautions needed to register the memory as uncached in the
page table of each process that has the dataspace attached.
Currently, the support for allocating DMA buffers is implemented for
Fiasco.OC only. On x86 platforms, it is generally not needed. But on
platforms with more relaxed cache coherence (such as ARM), user-level
device drivers should always use uncacheable memory for DMA transactions.
