Re: [PATCH] ARM: OMAP2+: Fix oops with LPAE and more than 2GB of memory

[Tony Lindgren <tony@atomide.com>]

* Lokesh Vutla <a0131933@ti.com> [151015 08:21]:
> +Richard
> 
> On Thursday 15 October 2015 07:35 PM, Tony Lindgren wrote:
> > * Lokesh Vutla <a0131933@ti.com> [151015 01:02]:
> >> Hi Tony,
> >>
> >> On Wednesday 14 October 2015 09:32 PM, Tony Lindgren wrote:
> >>> * Lokesh Vutla <a0131933@ti.com> [151013 20:53]:
> >>>> Hi Tony,
> >>>>
> >>>> On Wednesday 14 October 2015 04:43 AM, Tony Lindgren wrote:
> >>>>> On boards with more than 2GB of RAM booting goes wrong with things not working
> >>>>> and we're getting lots of l3 warnings:
> >>>>>
> >>>>> WARNING: CPU: 0 PID: 1 at drivers/bus/omap_l3_noc.c:147 l3_interrupt_handler+0x260/0x384()
> >>>>> 44000000.ocp:L3 Custom Error: MASTER MMC6 TARGET DMM1 (Idle): Data Access in User mode during Functional access
> >>>>> ...
> >>>>> [<c044e158>] (scsi_add_host_with_dma) from [<c04705c8>] (ata_scsi_add_hosts+0x5c/0x18c)
> >>>>> [<c04705c8>] (ata_scsi_add_hosts) from [<c046b13c>] (ata_host_register+0x150/0x2cc)
> >>>>> [<c046b13c>] (ata_host_register) from [<c046b38c>] (ata_host_activate+0xd4/0x124)
> >>>>> [<c046b38c>] (ata_host_activate) from [<c047f42c>] (ahci_host_activate+0x5c/0x194)
> >>>>> [<c047f42c>] (ahci_host_activate) from [<c0480854>] (ahci_platform_init_host+0x1f0/0x3f0)
> >>>>> [<c0480854>] (ahci_platform_init_host) from [<c047c9dc>] (ahci_probe+0x70/0x98)
> >>>>> [<c047c9dc>] (ahci_probe) from [<c04220cc>] (platform_drv_probe+0x54/0xb4)
> >>>>>
> >>>>> Let's fix the issue by enabling ZONE_DMA for LPAE.
> >>>>
> >>>> May I know on which platform you have reproduced this?
> >>>
> >>> This is on the 4GB version of isee igepv5 GEP0050-RB10
> >>>
> >>> https://isee.biz/products/igep-processor-boards/igepv5-omap5432
> >>>
> >>>> Just wondering what other changes you made for booting a OMAP5+ based
> >>>> board with more than 2GB.
> >>>
> >>> Just the minimal dts changes I posted yesterday to use shared dtsi file
> >>> for omap5-uevm variants. Then boot with something like this in the kernel
> >>> cmdline:
> >>>
> >>> mem=2032M@0x80000000 mem=2048M@0x300000000
> >> Is it the upper 2GB memory starts from 0x3_0000_0000? Looking at the
> >> Table 4-4. "AXI Access memory map" in TRM, it tells it starts from
> >> 0x2_0000_0000.(or am I missing something?)
> >>
> >> Any chance you tried doing memtest for all this memory?
> > 
> > Seems to work just fine, it's been up since I posted $subject patch., I tried
> > a kernel compile on it already earlier and just started memtester 3900M which
> > seems to only capable of testing 2924MB though.
> > 
> >> IIUC, It is not allowed to use the mix of L3 address mapping and MA
> >> physical address mapping. TRM specifies that
> >> "It is expected that the OS uses either the lower 2-GiB space and the
> >> lower aliased address of emif(a) and (b), or the continuous 8-GiB space
> >> and the upper aliasing of the emif(a) and (b) for all EMIF accesses."
> > 
> > I think that depends on the chip selects that can be used. The above
> > is probably for the case where all 8GB was to be used.
> 
> Richard, Do you agree with this?
> 
> > 
> >> I tried a similar 4GB setup and observed few stuff:
> >> - Need to have ARM_PV_FIXUP enabled something similar that is done in
> >> Keystone inorder to shift to higher address space.[1] [2]
> > 
> > Seems that's optional for 4GB.. But probably a must for 8GB :)
> > 
> >> - All the peripherals other than MPU, can access only 2GB. So we need to
> >> restrict the DMA and need an addresses translation. Along with this
> >> patch [3] [4] are needed.
> > 
> > Yes there's no memory accessible beyond 2GB for the DMA hardware. I'll
> > post an updated patch with the 2GB limit for dma_zone_size after some
> > more tests.
> > 
> > For the dma-ranges, looks like I have not hit that one yet. Which drivers
> > did you run into problems without that?
> 
> This is needed only when you completely shift to higher address space.

OK. Below is an updated version of the $subject patch.

Regards,

Tony

> >> [1]
> >> https://git.ti.com/~lokesh/ti-linux-kernel/lokesh-ti-linux-kernel/commit/be7d2d7e18f473e6078cd7c0b25ec3c58f40736b
> >> [2]
> >> https://git.ti.com/~lokesh/ti-linux-kernel/lokesh-ti-linux-kernel/commit/dd0a564ee565405bec5e9f58f0c97fb6714110ac
> >> [3]
> >> https://git.ti.com/~lokesh/ti-linux-kernel/lokesh-ti-linux-kernel/commit/985ed401e04926cb88b23646271dc96900abc50d
> >> [4]
> >> https://git.ti.com/~lokesh/ti-linux-kernel/lokesh-ti-linux-kernel/commit/c1f7568c4cc6f3146b7137783bd403967aabd0d8
> > 

8< ----------------------From c37732f6cea23d15faaaaa357cf698833c03ce05 Mon Sep 17 00:00:00 2001
Date: Fri, 16 Oct 2015 12:16:21 -0700
Subject: [PATCH] ARM: OMAP2+: Fix oops with LPAE and more than 2GB of memory

On boards with more than 2GB of RAM booting goes wrong with things not
working and we're getting lots of l3 warnings:

WARNING: CPU: 0 PID: 1 at drivers/bus/omap_l3_noc.c:147
l3_interrupt_handler+0x260/0x384()
44000000.ocp:L3 Custom Error: MASTER MMC6 TARGET DMM1 (Idle):
Data Access in User mode during Functional access
...
[<c044e158>] (scsi_add_host_with_dma) from [<c04705c8>]
(ata_scsi_add_hosts+0x5c/0x18c)
[<c04705c8>] (ata_scsi_add_hosts) from [<c046b13c>]
(ata_host_register+0x150/0x2cc)
[<c046b13c>] (ata_host_register) from [<c046b38c>]
(ata_host_activate+0xd4/0x124)
[<c046b38c>] (ata_host_activate) from [<c047f42c>]
(ahci_host_activate+0x5c/0x194)
[<c047f42c>] (ahci_host_activate) from [<c0480854>]
(ahci_platform_init_host+0x1f0/0x3f0)
[<c0480854>] (ahci_platform_init_host) from [<c047c9dc>]
(ahci_probe+0x70/0x98)
[<c047c9dc>] (ahci_probe) from [<c04220cc>]
(platform_drv_probe+0x54/0xb4)

Let's fix the issue by enabling ZONE_DMA for LPAE. Note that we need to
limit dma_zone_size to 2GB as the rest of the RAM is beyond the 4GB limit.

Let's also fix things for dra7 as done in similar patches in the TI tree
by Lokesh Vutla <lokeshvutla@ti.com>.

Signed-off-by: Tony Lindgren <tony@atomide.com>

--- a/arch/arm/mach-omap2/Kconfig
+++ b/arch/arm/mach-omap2/Kconfig
@@ -49,6 +49,7 @@ config SOC_OMAP5
 	select OMAP_INTERCONNECT
 	select OMAP_INTERCONNECT_BARRIER
 	select PM_OPP if PM
+	select ZONE_DMA if ARM_LPAE
 
 config SOC_AM33XX
 	bool "TI AM33XX"
@@ -78,6 +79,7 @@ config SOC_DRA7XX
 	select OMAP_INTERCONNECT
 	select OMAP_INTERCONNECT_BARRIER
 	select PM_OPP if PM
+	select ZONE_DMA if ARM_LPAE
 
 config ARCH_OMAP2PLUS
 	bool
--- a/arch/arm/mach-omap2/board-generic.c
+++ b/arch/arm/mach-omap2/board-generic.c
@@ -243,6 +243,9 @@ static const char *const omap5_boards_compat[] __initconst = {
 };
 
 DT_MACHINE_START(OMAP5_DT, "Generic OMAP5 (Flattened Device Tree)")
+#if defined(CONFIG_ZONE_DMA) && defined(CONFIG_ARM_LPAE)
+	.dma_zone_size	= SZ_2G,
+#endif
 	.reserve	= omap_reserve,
 	.smp		= smp_ops(omap4_smp_ops),
 	.map_io		= omap5_map_io,
@@ -288,6 +291,9 @@ static const char *const dra74x_boards_compat[] __initconst = {
 };
 
 DT_MACHINE_START(DRA74X_DT, "Generic DRA74X (Flattened Device Tree)")
+#if defined(CONFIG_ZONE_DMA) && defined(CONFIG_ARM_LPAE)
+	.dma_zone_size	= SZ_2G,
+#endif
 	.reserve	= omap_reserve,
 	.smp		= smp_ops(omap4_smp_ops),
 	.map_io		= dra7xx_map_io,
@@ -308,6 +314,9 @@ static const char *const dra72x_boards_compat[] __initconst = {
 };
 
 DT_MACHINE_START(DRA72X_DT, "Generic DRA72X (Flattened Device Tree)")
+#if defined(CONFIG_ZONE_DMA) && defined(CONFIG_ARM_LPAE)
+	.dma_zone_size	= SZ_2G,
+#endif
 	.reserve	= omap_reserve,
 	.map_io		= dra7xx_map_io,
 	.init_early	= dra7xx_init_early,