On Wed, Jun 22, 2022 at 07:51:11PM +0200, Ahmad Fatoum wrote:
> Boards that get their memory from device tree are prone to breakage if
> upstream decides to remove the /memory node or renders it unusable[0]
> or to disable the DRAM controller device node[1] used to dynamically
> compute the size. While this needs to be fixed properly on a
> case-by-case basis, soften the blow by using the memory size specified
> by low level code as a fallback instead of just throwing the towel.
>
> [0]: aa68c6bd3615 ("arm: rk3288-phycore-som: Fix memory node")
> [1]: 0529149b2756 ("arm: imx8mq: re-enable DDRC for Barebox")
> Signed-off-by: Ahmad Fatoum <[email protected]>
> ---
> arch/arm/cpu/mmu-common.c | 15 +++++++++++++--
> arch/arm/cpu/start.c | 8 ++++++++
> arch/arm/include/asm/barebox-arm.h | 1 +
> 3 files changed, 22 insertions(+), 2 deletions(-)
Applied, thanks
Sascha
>
> diff --git a/arch/arm/cpu/mmu-common.c b/arch/arm/cpu/mmu-common.c
> index 2ef1fa231f39..488a189f1c06 100644
> --- a/arch/arm/cpu/mmu-common.c
> +++ b/arch/arm/cpu/mmu-common.c
> @@ -9,6 +9,7 @@
> #include <dma.h>
> #include <mmu.h>
> #include <asm/system.h>
> +#include <asm/barebox-arm.h>
> #include <memory.h>
> #include "mmu.h"
>
> @@ -58,14 +59,24 @@ void dma_free_coherent(void *mem, dma_addr_t dma_handle,
> size_t size)
>
> static int mmu_init(void)
> {
> - if (list_empty(&memory_banks))
> + if (list_empty(&memory_banks)) {
> + resource_size_t start;
> + int ret;
> +
> /*
> * If you see this it means you have no memory registered.
> * This can be done either with arm_add_mem_device() in an
> * initcall prior to mmu_initcall or via devicetree in the
> * memory node.
> */
> - panic("MMU: No memory bank found! Cannot continue\n");
> + pr_emerg("No memory bank registered. Limping along with initial
> memory\n");
> +
> + start = arm_mem_membase_get();
> + ret = barebox_add_memory_bank("initmem", start,
> + arm_mem_endmem_get() - start);
> + if (ret)
> + panic("");
> + }
>
> __mmu_init(get_cr() & CR_M);
>
> diff --git a/arch/arm/cpu/start.c b/arch/arm/cpu/start.c
> index c61db668658b..14cc310312ab 100644
> --- a/arch/arm/cpu/start.c
> +++ b/arch/arm/cpu/start.c
> @@ -28,6 +28,7 @@
> unsigned long arm_stack_top;
> static unsigned long arm_barebox_size;
> static unsigned long arm_endmem;
> +static unsigned long arm_membase;
> static void *barebox_boarddata;
> static unsigned long barebox_boarddata_size;
>
> @@ -114,6 +115,12 @@ unsigned long arm_mem_endmem_get(void)
> }
> EXPORT_SYMBOL_GPL(arm_mem_endmem_get);
>
> +unsigned long arm_mem_membase_get(void)
> +{
> + return arm_membase;
> +}
> +EXPORT_SYMBOL_GPL(arm_mem_membase_get);
> +
> static int barebox_memory_areas_init(void)
> {
> if(barebox_boarddata)
> @@ -148,6 +155,7 @@ __noreturn __no_sanitize_address void
> barebox_non_pbl_start(unsigned long membas
>
> pr_debug("memory at 0x%08lx, size 0x%08lx\n", membase, memsize);
>
> + arm_membase = membase;
> arm_endmem = endmem;
> arm_stack_top = arm_mem_stack_top(membase, endmem);
> arm_barebox_size = barebox_size;
> diff --git a/arch/arm/include/asm/barebox-arm.h
> b/arch/arm/include/asm/barebox-arm.h
> index 15b3b6c44479..8240cce9bf5b 100644
> --- a/arch/arm/include/asm/barebox-arm.h
> +++ b/arch/arm/include/asm/barebox-arm.h
> @@ -84,6 +84,7 @@ static inline void boarddata_create(void *adr, u32 machine)
> u32 barebox_arm_machine(void);
>
> unsigned long arm_mem_ramoops_get(void);
> +unsigned long arm_mem_membase_get(void);
> unsigned long arm_mem_endmem_get(void);
>
> struct barebox_arm_boarddata *barebox_arm_get_boarddata(void);
> --
> 2.30.2
>
>
>
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