[PATCH v2] of: make MAX_RESERVED_REGIONS configurable

[PATCH v2] of: make MAX_RESERVED_REGIONS configurable

[Calvin Zhang]

MAX_RESERVED_REGIONS has changed several times. Max reserved regions
count grows bigger as more SOC subsystems require reserved regions.

Add a Kconfig for it so that when properly configured, the static
reserved_mem array consumes less memory on systems with few reserved
regions.

Signed-off-by: Calvin Zhang <calvinzhang.cool@gmail.com>
---
 drivers/of/Kconfig           | 10 ++++++++++
 drivers/of/of_reserved_mem.c |  3 +--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/of/Kconfig b/drivers/of/Kconfig
index 80b5fd44ab1c..47ffff9f6aba 100644
--- a/drivers/of/Kconfig
+++ b/drivers/of/Kconfig
@@ -73,6 +73,16 @@ config OF_IRQ
 config OF_RESERVED_MEM
 	def_bool OF_EARLY_FLATTREE
 
+config OF_MAX_RESERVED_REGIONS
+	int "Maximum count of reserved regions"
+	depends on OF_RESERVED_MEM
+	default 64
+	help
+	  Reserved regions in /reserved-memory node includes static
+	  reservations with fixed location and dynamic ones for device
+	  CMA regions. This parameter sets the maximum number of reserved
+	  regions in the system.
+
 config OF_RESOLVE
 	bool
 
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 9c0fb962c22b..d90ae4c03011 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -25,8 +25,7 @@
 
 #include "of_private.h"
 
-#define MAX_RESERVED_REGIONS	64
-static struct reserved_mem reserved_mem[MAX_RESERVED_REGIONS];
+static struct reserved_mem reserved_mem[CONFIG_OF_MAX_RESERVED_REGIONS];
 static int reserved_mem_count;
 
 static int __init early_init_dt_alloc_reserved_memory_arch(phys_addr_t size,
-- 
2.30.2

Re: [PATCH v2] of: make MAX_RESERVED_REGIONS configurable

[Rob Herring]

On Mon, Nov 15, 2021 at 1:33 AM Calvin Zhang <calvinzhang.cool@gmail.com> wrote:
>
> MAX_RESERVED_REGIONS has changed several times. Max reserved regions
> count grows bigger as more SOC subsystems require reserved regions.
>
> Add a Kconfig for it so that when properly configured, the static
> reserved_mem array consumes less memory on systems with few reserved
> regions.

Please read prior discussions:

https://lore.kernel.org/all/?q=of+MAX_RESERVED_REGIONS

And these 2 in particular:

https://lore.kernel.org/all/CAL_JsqJQcWsguwfehAoaRf4o-2VqXxSzKzTqg7s4+N1bp=6V5Q@mail.gmail.com/
https://lore.kernel.org/all/CAL_JsqLGvUYQmCGXLgSO+6kFj2i87dpaTbMGbyu5oMt=eeu35A@mail.gmail.com/

Re: [PATCH v2] of: make MAX_RESERVED_REGIONS configurable

[Calvin Zhang]

On Mon, Nov 15, 2021 at 08:05:45AM -0600, Rob Herring wrote:
>On Mon, Nov 15, 2021 at 1:33 AM Calvin Zhang <calvinzhang.cool@gmail.com> wrote:
>>
>> MAX_RESERVED_REGIONS has changed several times. Max reserved regions
>> count grows bigger as more SOC subsystems require reserved regions.
>>
>> Add a Kconfig for it so that when properly configured, the static
>> reserved_mem array consumes less memory on systems with few reserved
>> regions.
>
>Please read prior discussions:
>
>https://lore.kernel.org/all/?q=of+MAX_RESERVED_REGIONS
>
>And these 2 in particular:
>
>https://lore.kernel.org/all/CAL_JsqJQcWsguwfehAoaRf4o-2VqXxSzKzTqg7s4+N1bp=6V5Q@mail.gmail.com/
>https://lore.kernel.org/all/CAL_JsqLGvUYQmCGXLgSO+6kFj2i87dpaTbMGbyu5oMt=eeu35A@mail.gmail.com/
>
OK. I will try to make the array dynamic.

Thanks,
Calvin