| Message ID | 1317122493-26452-1-git-send-email-premi@ti.com |
|---|---|
| State | Changes Requested |
| Headers | show |
On 09/27/11 14:21, Sanjeev Premi wrote: > In absence of this argument, Linux kernel doesn't boot. > > Default value has been set to 128M to ensure that > Linux kernel boots on older EVMs as well. This change affects all EVMs, unless they explicitly change/remove the memsize variable or change the *args variables. Can't the get_ram_size() function be used for detecting the actual amount of RAM? and then the memory tag or FDT equivalent (if there is one) used to pass the memory size information? > > Signed-off-by: Sanjeev Premi <premi@ti.com> > Cc: Sandeep Paulraj <s-paulraj@ti.com> > --- > > This patch has been created against u-boot-ti/next. > > include/configs/omap3_evm.h | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/include/configs/omap3_evm.h b/include/configs/omap3_evm.h > index 7af30c2..ea51216 100644 > --- a/include/configs/omap3_evm.h > +++ b/include/configs/omap3_evm.h > @@ -200,11 +200,14 @@ > "loadaddr=0x82000000\0" \ > "usbtty=cdc_acm\0" \ > "mmcdev=0\0" \ > + "memsize=128M\0" \ > "console=ttyO0,115200n8\0" \ > "mmcargs=setenv bootargs console=${console} " \ > + "mem=${memsize}\0 " \ > "root=/dev/mmcblk0p2 rw " \ > "rootfstype=ext3 rootwait\0" \ > "nandargs=setenv bootargs console=${console} " \ > + "mem=${memsize}\0 " \ > "root=/dev/mtdblock4 rw " \ > "rootfstype=jffs2\0" \ > "loadbootscript=fatload mmc ${mmcdev} ${loadaddr} boot.scr\0" \
> -----Original Message----- > From: Igor Grinberg [mailto:grinberg@compulab.co.il] > Sent: Tuesday, September 27, 2011 5:35 PM > To: Premi, Sanjeev > Cc: u-boot@lists.denx.de > Subject: Re: [U-Boot] [PATCH] omap3evm: Pass 'mem' argument > to linux kernel Sorry missed this mail earlier... > > On 09/27/11 14:21, Sanjeev Premi wrote: > > In absence of this argument, Linux kernel doesn't boot. > > > > Default value has been set to 128M to ensure that > > Linux kernel boots on older EVMs as well. > > This change affects all EVMs, unless they explicitly change/remove > the memsize variable or change the *args variables. Today without this patch, all EVMs should anyway be broken :( ...but may be working as users may have their own bootargs with "mem=XYZM" in their bootargs. The patch only ensures that the kernel would boot if there was no "saved" environment e.g. when environment partition is erased. or when u-boot is flashed on new boards. > > Can't the get_ram_size() function be used for detecting the actual > amount of RAM? and then the memory tag or FDT equivalent > (if there is one) used to pass the memory size information? > Yes something like this can be done, but that would mean string manipulation at run-time. Question is - when we should/ shouldn't do this manipulation. If user wants to explicitly pass only a portion of memory to Linux using environment variables, we shouldn't be manipulating the bootargs. ~sanjeev [snip]...[snip]
Dear Sanjeev Premi, In message <1317122493-26452-1-git-send-email-premi@ti.com> you wrote: > In absence of this argument, Linux kernel doesn't boot. > > Default value has been set to 128M to ensure that > Linux kernel boots on older EVMs as well. > > Signed-off-by: Sanjeev Premi <premi@ti.com> > Cc: Sandeep Paulraj <s-paulraj@ti.com> > --- Why do we need to pass any mem= argument at all? This should never be necessary. If it is, then this is a bug in the Linux kernel and needs to be fixed there. Best regards, Wolfgang Denk
Dear "Premi, Sanjeev", In message <B85A65D85D7EB246BE421B3FB0FBB59302577A8A72@dbde02.ent.ti.com> you wrote: > > > Can't the get_ram_size() function be used for detecting the actual > > amount of RAM? and then the memory tag or FDT equivalent > > (if there is one) used to pass the memory size information? > > Yes something like this can be done, but that would mean string > manipulation at run-time. Question is - when we should/ shouldn't > do this manipulation. I don't understand what you are trying to say. There are two possibilities: - In a FDT enabled kernel, memory information is passed in the device tree; no "string manipulation" is needed anywhere. If the user decides to overwrite the auto-detected settings by using a "mem=" boot argument, this is his decision and of course he can do so. - Without FDT support, on ARM systems we pass a memory information in one or more ATAG_MEM entries. Again, no "string manipulation" is needed anywhere. > If user wants to explicitly pass only a portion of memory to Linux > using environment variables, we shouldn't be manipulating the > bootargs. This statement makes even less ense to me. Passing a "mem=" boot argument is the official, documented way to acchive this. So what makes you think we should not pass such a boot argument? Best regards, Wolfgang Denk
diff --git a/include/configs/omap3_evm.h b/include/configs/omap3_evm.h index 7af30c2..ea51216 100644 --- a/include/configs/omap3_evm.h +++ b/include/configs/omap3_evm.h @@ -200,11 +200,14 @@ "loadaddr=0x82000000\0" \ "usbtty=cdc_acm\0" \ "mmcdev=0\0" \ + "memsize=128M\0" \ "console=ttyO0,115200n8\0" \ "mmcargs=setenv bootargs console=${console} " \ + "mem=${memsize}\0 " \ "root=/dev/mmcblk0p2 rw " \ "rootfstype=ext3 rootwait\0" \ "nandargs=setenv bootargs console=${console} " \ + "mem=${memsize}\0 " \ "root=/dev/mtdblock4 rw " \ "rootfstype=jffs2\0" \ "loadbootscript=fatload mmc ${mmcdev} ${loadaddr} boot.scr\0" \
In absence of this argument, Linux kernel doesn't boot. Default value has been set to 128M to ensure that Linux kernel boots on older EVMs as well. Signed-off-by: Sanjeev Premi <premi@ti.com> Cc: Sandeep Paulraj <s-paulraj@ti.com> --- This patch has been created against u-boot-ti/next. include/configs/omap3_evm.h | 3 +++ 1 files changed, 3 insertions(+), 0 deletions(-)