Hi all,
I read a kernel image form SPI Flash using "sf" command of u-boot as below:
"sf read ${kloadaddr} ${spi_src_addr} ${spi_img_siz}"
The reading process takes about 10 seconds when the <spi_img_siz> 7M Bytes！ That is the speed of reading SPI Flash is only 5.6Mbps.
I set SPI CLK to 12MHz, and I find there is a period of CLK IDLE time between two groups of continuous eight CLK. The period of CLK IDLE time is about 900ns. I have also configured the SPI CLK to 24MHz and 48MHz, but the speed of reading is not been significantly improved.
To test the speed in Linux, the test data on WIKI is about 1.22MB/s for reading while SPICLK is set to 24MHz. http://processors.wiki.ti.com/index.php/AM335x-PSP_04.06.00.07_Features_and_Performance_Guide#Performance_and_Benchmarks_2
I modified the SPICLK to 48MHz, and the result is about 2M/s.
Why the speed of reading SPI Flash is so slow？What can I do to speed up the reading？
Can anyone help me？ I use the broad "AM335x Starter Kit" for testing.
