topic Question regarding System Memory and RAM ls1021a in Layerscape https://community.nxp.com/t5/Layerscape/Question-regarding-System-Memory-and-RAM-ls1021a/m-p/1067484#M6115 <HTML><HEAD></HEAD><BODY><P>Hi,</P><P>Please see this below:</P><P><span class="lia-inline-image-display-wrapper" image-alt="pastedImage_1.png"><img src="https://community.nxp.com/t5/image/serverpage/image-id/107354i69650108E0E2F681/image-size/large?v=v2&amp;px=999" role="button" title="pastedImage_1.png" alt="pastedImage_1.png" /></span></P><P></P><P>A 32-bit CPU the system memory for it is from 0x00000000 - 0xFFFFFFFFF</P><P></P><P>(1)So system memory is not only RAM is that correct? if so when I/O mapped devices are accessed by the CPU the physical memory addresses (I know it will map to virtual memory first) are on the RAM or the system memory?</P><P></P><P>(2) the RAM is made up of kernel memory and usersapce memory, when a CPU wants to access a driver and configure it let's say ethernet (for example whenever the kernel gets loaded) is this access done from system memory or in the RAM?</P></BODY></HTML> Sun, 24 May 2020 16:36:34 GMT jiye 2020-05-24T16:36:34Z Question regarding System Memory and RAM ls1021a https://community.nxp.com/t5/Layerscape/Question-regarding-System-Memory-and-RAM-ls1021a/m-p/1067484#M6115 <HTML><HEAD></HEAD><BODY><P>Hi,</P><P>Please see this below:</P><P><span class="lia-inline-image-display-wrapper" image-alt="pastedImage_1.png"><img src="https://community.nxp.com/t5/image/serverpage/image-id/107354i69650108E0E2F681/image-size/large?v=v2&amp;px=999" role="button" title="pastedImage_1.png" alt="pastedImage_1.png" /></span></P><P></P><P>A 32-bit CPU the system memory for it is from 0x00000000 - 0xFFFFFFFFF</P><P></P><P>(1)So system memory is not only RAM is that correct? if so when I/O mapped devices are accessed by the CPU the physical memory addresses (I know it will map to virtual memory first) are on the RAM or the system memory?</P><P></P><P>(2) the RAM is made up of kernel memory and usersapce memory, when a CPU wants to access a driver and configure it let's say ethernet (for example whenever the kernel gets loaded) is this access done from system memory or in the RAM?</P></BODY></HTML> Sun, 24 May 2020 16:36:34 GMT https://community.nxp.com/t5/Layerscape/Question-regarding-System-Memory-and-RAM-ls1021a/m-p/1067484#M6115 jiye 2020-05-24T16:36:34Z Re: Question regarding System Memory and RAM ls1021a https://community.nxp.com/t5/Layerscape/Question-regarding-System-Memory-and-RAM-ls1021a/m-p/1067485#M6116 <HTML><HEAD></HEAD><BODY><P>1) Please refer to the QorIQ LS1021A Reference Manual, Table 2-1. System memory map.</P><P>2) Concerning the eTSEC Ethernet driver refer to the LSDK Documentation:</P><P><A class="link-titled" href="https://docs.nxp.com/bundle/GUID-51EEFEDB-ABD5-40C0-BEBD-6527B3494D57/page/GUID-3859CD3C-A399-48B1-AEBE-BD4EC0ED9CA2.html" title="https://docs.nxp.com/bundle/GUID-51EEFEDB-ABD5-40C0-BEBD-6527B3494D57/page/GUID-3859CD3C-A399-48B1-AEBE-BD4EC0ED9CA2.html">Linux Ethernet Driver for eTSEC</A>&nbsp;</P></BODY></HTML> Sun, 24 May 2020 17:15:18 GMT https://community.nxp.com/t5/Layerscape/Question-regarding-System-Memory-and-RAM-ls1021a/m-p/1067485#M6116 ufedor 2020-05-24T17:15:18Z