UM0851 Datasheet, PDF (162/245 Pages) STMicroelectronics – SPEAr is a family of highly customizable ARM-based embedded

Accelerator engine device drivers
UM0851
6.1.3
else if (pid > 0)
// parent
{
jpegread();
wait(0);
}
else
// failed to fork
{
printf("Cant create child\n");
exit(1);
}
}
JPEG device driver performance
The JPEG driver performance has been measured in the following environment:
● Hardware: ARM926EJS (333 MHz), SPEAr600, SPEAr300, SPEar310 and SPEAr320
evaluation boards.
● Kernel: linux-2.6.27
Configuration options
Table 43. JPEG driver configuration options
Configuration option
Comment
CONFIG_SPEAR_JPEG_SYN
This option enables the SPEAr JPEG driver.
CONFIG_SPEAR_JPEG_SYN_DEBUG
This option enables debug prints in the JPEG
driver.
CONFIG_SPEAR_DMAC_PL080
This option must be selected for JPEG
operations. This will enable the DMA driver.
6.1.4
References
● SPEAr JPEG Driver "drivers/char/spr_jpeg_syn.c, drivers/char/spr_jpeg_syn.h and
include/linux/spr_jpeg_syn_usr.h"
6.2
6.2.1
General purpose DMA (DMAC) driver
All SPEAr MPUs are equipped with a general purpose DMA Controller which provides
several DMA channels that can be used to off load the CPU from some of the memory
copying tasks. This section describes the details of the DMAC driver.
Hardware overview
Direct memory access (DMA) allows certain subsystems within the SPEAr MPU to access
system memory for reading and/or writing independently of the CPU and to transfer data
without subjecting the CPU to a heavy overhead.
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Doc ID 16604 Rev 2