MIU User Guide

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REVISION HISTORY

Revision No.	Description	Date
1.0	Initial release	05/06/2025

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1. Overview

Memory Interface Unit, abbreviated as MIU, is primarily responsible for driving DRAM hardware. It provides functions such as initializing DRAM, managing continuous memory regions (MMU), and regulating the priority of direct hardware IP read and write operations.

图1-1 MIU框架

2. Keyword Description

IP : Intellectual Property, which connects various module components of the MIU module.

ARBITER : An arbiter used to receive and manage requests for memory access from various modules.

DDRC : Manager, used for handling the access protocol and logical management of DDR memory.

DDRPHY : A physical channel used to convert the digital logic signals emitted by the DDRC into analog signals that conform to the electrical characteristics of DRAM.

3. Function Description

Memory Management Unit (MMU): The MMU is responsible for handling and responding to memory access requests from the Central Processing Unit (CPU).

Address Protection: Address protection can restrict an IP to only perform fixed-pattern memory access operations. It also provides alerts in case of unexpected behavior.

Multistage Arbitration: Multistage arbitration typically uses a multi-level arbitration processor to manage memory access requests from IPs.

Bandwidth Report: The bandwidth report supports real-time statistics on DDR bandwidth usage.

Supports DDR3/LPDDR3/DDR4/LPDDR4/LPDDR4x and other DDR memory chips.

Supports low-power design: Power saving can be achieved by controlling the DDR's entry into self-refresh mode.

4. Kernel Usage Introduction

4.1. Kernel Config Configuration

For Linux to use MMU, configuration is required (enabled by default):

CONFIG_SGS_MIU=y

The configurations selected in menuconfig are as follows:

Device drivers->
    [*] Sgs SoC platform drivers->
        <*> Sgs MIU

4.2. Module Usage Introduction

4.2.1 SYSFS Usage Methods

1. /sys/devices/system/miu/miu0/bist

   Supports configuring simulated IP to access DDR for testing.

   Command format: echo [mode] [rwmode] [bist-x] > /sys/devices/system/miu/miu0/bist

   Parameter	Description	Notes
   mode	Configurable modes: oneshot (single access) or loop (continuous access)
   rwmode	Configurable modes: rw (read-write), wo (write-only), ro (read-only)
   bist-x	Configures which BIST to launch: all for all, 0/ 1/ 2 for individual BIST channels	Use cat bist node to view each BIST channel's configuration

   Example: Launch all BIST channels for single DDR access

   echo oneshot rw all > /sys/devices/system/miu/miu0/bist

   Example: Launch all BIST channels for continuous DDR access

   Start: echo loop rw all > /sys/devices/system/miu/miu0/bist

   Stop: echo stop all > /sys/devices/system/miu/miu0/bist

2. /sys/devices/system/miu/miu0/bw

   Supports bandwidth usage statistics.

   Example: Check bandwidth usage

   Configure 128 sampling cycles (default: 32 cycles): echo 128 > /sys/devices/system/miu/miu0/bw

   View collected bandwidth data: cat /sys/devices/system/miu/miu0/bw

3. /sys/devices/system/miu/miu0/client

   Supports configuring and viewing priority parameters for each client.

   Priority configuration command format: echo qos [rwmode] [clientid] [level] > /sys/devices/system/miu/miu0/client

   Parameter	Description	Notes
   rwmode	Configurable as r (read) or w (write)
   clientid	ID of the IP to be configured
   level	Configurable levels 0-7 (0=lowest priority, 7=highest priority)

   Example: Set write priority of bist0 to highest

   echo qos w 0xf 7 > /sys/devices/system/miu/miu0/client

   IP access blocking command format: echo mask [rwmode] [clientid] [enable] > /sys/devices/system/miu/miu0/client

   Parameter	Description	Notes
   rwmode	Configurable as r (read) or w (write)
   clientid	ID of the IP to be configured
   enable	0=disable, 1=enable

   Example: Block write operations of bist0

   echo mask w 0xf 1 > /sys/devices/system/miu/miu0/client

   IP access restriction command format: echo flowctrl [rwmode] [clientid] [enable] [maskperiod] [passperiod] > /sys/ devices/system/miu/miu0/client

   Parameter	Description	Notes
   rwmode	Configurable as r (read) or w (write)
   clientid	ID of the IP to be configured
   enable	0=disable, 1=enable
   maskperiod	Blocking period (0-ff)	Higher value=stronger restriction
   passperiod	Passing period (0-3)	Lower value=stronger restriction

   Example: Apply stronger write restrictions to bist0

   Enable: echo flowctrl w 0xf 1 0xff 1 > /sys/devices/system/miu/miu0/client

   Disable: echo flowctrl w 0xf 0 > /sys/devices/system/miu/miu0/client

4. /sys/devices/system/miu/miu0/dram_info

   Supports viewing current DDR information.

   Example: Check current DDR information

   cat /sys/devices/system/miu/miu0/dram_info

   

5. /sys/devices/system/miu/miu0/ip_table

   Supports viewing IP-to-client mapping.

   Example: Check IP-client correspondence

   cat /sys/devices/system/miu/miu0/ip_table

   

5. API Reference

This functional module provides the following interfaces:

API	Function
drv_miu_module_reset	Perform reset based on the IP client name
drv_miu_module_reset_byid	Perform reset based on the IP client id
drv_miu_module_reset_bymultipleid	Perform reset based on the IP client id list
drv_miu_module_mask	Perform mask based on the IP client name
drv_miu_module_mask_byid	Perform mask based on the IP client id
drv_miu_module_mask_bymultipleid	Perform mask based on the IP client id list
drv_miu_client_id_to_name	Obtain the IP client name based on the IP client id
drv_miu_protect_query	Obtain the current free protect id
drv_miu_protect_enable	Enable address protection for the set address range
drv_miu_protect_disable	Disable the address protection for the corresponding protect id
drv_miu_protect_append_id	Add the corresponding IP to the protect list
drv_miu_protect_remove_id	Remove the corresponding IP from the protect list
drv_miu_protect_default_kernel_whitelist	Obtain the current default whitelist
drv_miu_protect_default_kernel_blacklist	Obtain the current default blacklist
drv_miu_protect_list	Retrieve the protection list information based on the protect ID
drv_miu_protect_status	Retrieve the protection status information based on the protect ID
drv_miu_protect_address	Retrieve the protection address information based on the protect ID
drv_miu_protect_set_panic	Enable or disable panic when protection is triggered
drv_miu_mmu_set_page_size	Configure the MMU page size
drv_miu_mmu_get_page_size	Obtain the MMU page size
drv_miu_mmu_set_region	Establish a mapping relationship between VPA and PA regions
drv_miu_mmu_map_entry	Establish a mapping relationship between VPA and PA entries
drv_miu_mmu_unmap_entry	Remove the mapping relationship between VPA and PA entries
drv_miu_mmu_query_entry	Obtain the PA entry id corresponding to the current VPA entry
drv_miu_mmu_enable	Enable or disable MMU functionality
drv_miu_mmu_reset	Reset the MIU
drv_mmu_callback_func	Function about interrupt call for mmu
drv_miu_dram_info	Obtain the parameter information of the currently used DRAM
drv_miu_init	Initialize the MIU
drv_miu_phy_to_miu	Conversion from physical address to MIU address
drv_miu_addr_to_phy	Conversion from MIU address to physical address

5.1 Client Function Section

5.1.1 drv_miu_module_reset

• Function

  Perform reset based on the IP client name.

• Grammar

  s32 drv_miu_module_reset(char* ClientName, DRV_MIU_OP_MODE Op);
  

• Parameter

  Parameter name	Description	Input/Output
  ClientName	IP client name	Input
  Op	operation enum	Input

  The details of Op are as shown in the following enumeration types:

  typedef enum
  {
      DRV_MIU_OP_MODE_RD = 0, //read command
      DRV_MIU_OP_MODE_WR, //write command
      DRV_MIU_OP_MODE_MAX, //invalid
  } DRV_MIU_OP_MODE;
  

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.1.2 drv_miu_module_reset_byid

• Function

  Perform reset based on the IP client id.

• Grammar

  s32 drv_miu_module_reset_byid(miu_client_id ClientID, DRV_MIU_OP_MODE Op);
  

• Parameter

  Parameter name	Description	Input/Output
  ClientID	IP client id	Input
  Op	operation enum	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.1.3 drv_miu_module_reset_bymultipleid

• Function

  Perform reset based on the IP client id list whose id all belong to the same group.

• Grammar

  s32 drv_miu_module_reset_bymultipleid(u32 *ClientIDList, u32 ClientIDListLen, DRV_MIU_OP_MODE Op);
  

• Parameter

  Parameter name	Description	Input/Output
  ClientIDList	IP client id array whose id all belong to the same group	Input
  ClientIDListLen	IP client id array length	Input
  Op	operation enum	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files：drv_miu.h

5.1.4 drv_miu_module_mask

• Function

  Perform mask based on the IP client name.

• Grammar

  s32 drv_miu_module_mask(char *ClientName, DRV_MIU_OP_MODE Op, u8 mask);
  

• Parameter

  Parameter name	Description	Input/Output
  ClientName	IP client name	Input
  Op	operation enum	Input
  mask	open or close mask	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.1.5 drv_miu_module_mask_byid

• Function

  Perform mask based on the IP client id.

• Grammar

  s32 drv_miu_module_mask_byid(miu_client_id ClientID, DRV_MIU_OP_MODE Op, u8 mask);
  

• Parameter

  Parameter name	Description	Input/Output
  ClientID	IP client id	Input
  Op	operation enum	Input
  mask	open or close mask	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.1.6 drv_miu_module_mask_bymultipleid

• Function

  Perform mask based on the IP client id list whose id all belong to the same group.

• Grammar

  s32 drv_miu_module_mask_bymultipleid(u32 *ClientIDList, u32 ClientIDListLen, DRV_MIU_OP_MODE Op, u8 mask);
  

• Parameter

  Parameter name	Description	Input/Output
  ClientIDList	IP client id array whose id all belong to the same group	Input
  ClientIDListLen	IP client id array length	Input
  Op	operation enum	Input
  mask	open or close mask	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files：drv_miu.h

5.1.7 drv_miu_client_id_to_name

• Function

  Obtain the IP client name based on the IP client id.

• Grammar

  char* drv_miu_client_id_to_name(u16 id, DRV_MIU_OP_MODE Op);
  

• Parameter

  Parameter name	Description	Input/Output
  id	IP client id	Input
  Op	operation enum	Input

• Return Value

  • success: return client name

  • fail: NULL

• Rely

  • Header Files: drv_miu.h

5.2 Protect Function Section

5.2.1 drv_miu_protect_query

• Function

  Obtain the current free protect id.

• Grammar

  u8 drv_miu_protect_query(u8 mmu);
  

• Parameter

  Parameter name	Description	Input/Output
  mmu	Control whether it is MIU protect or MMU protect	Input

• Return Value

  • return protect id

• Rely

  • Header Files: drv_miu.h

5.2.2 drv_miu_protect_enable

• Function

  Enable address protection for the set address range

• Grammar

  s32 drv_miu_protect_enable(u8 index, u16* list, u8 invert, ss_phys_addr_t start, ss_phys_addr_t end);
  

• Parameter

  Parameter name	Description	Input/Output
  index	protect id	Input
  list	The ID list of protected IPs that need to be set	Input
  invert	Control the whitelist or the blacklist	Input
  start	Start address	Input
  end	End address	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.2.3 drv_miu_protect_disable

• Function

  Disable the address protection for the corresponding protect id.

• Grammar

  s32 drv_miu_protect_disable(u8 index);
  

• Parameter

  Parameter name	Description	Input/Output
  index	protect id	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.2.4 drv_miu_protect_append_id

• Function

  Add the corresponding IP to the protect list.

• Grammar

  s32 drv_miu_protect_append_id(u8 index, u16 id);
  

• Parameter

  Parameter name	Description	Input/Output
  index	protect id	Input
  id	IP client id	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.2.5 drv_miu_protect_remove_id

• Function

  Remove the corresponding IP from the protect list.

• Grammar

  s32 drv_miu_protect_remove_id(u8 index, u16 id);
  

• Parameter

  Parameter name	Description	Input/Output
  index	protect id	Input
  id	IP client id	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.2.6 drv_miu_protect_default_kernel_whitelist

• Function

  Obtain the current default whitelist.

• Grammar

  u16* drv_miu_protect_default_kernel_whitelist(void);
  

• Parameter

  • void

• Return Value

  • Return the ID array of the default whitelist

• Rely

  • Header Files: drv_miu.h

5.2.7 drv_miu_protect_default_kernel_blacklist

• Function

  Obtain the current default blacklist.

• Grammar

  u16* drv_miu_protect_default_kernel_blacklist(void);
  

• Parameter

  • void

• Return Value

  • Return the ID array of the default blacklist

• Rely

  • Header Files: drv_miu.h

5.2.8 drv_miu_protect_list

• Function

  Retrieve the protection list information based on the protect ID.

• Grammar

  u16* drv_miu_protect_list(u8 index, u8* invert);
  

• Parameter

  Parameter name	Description	Input/Output
  index	protect id	Input
  invert	Control the whitelist or the blacklist	Input

• Return Value

  • success: Return the ID array of protect

  • fail: NULL

• Rely

  • Header Files: drv_miu.h

5.2.9 drv_miu_protect_status

• Function

  Retrieve the protection status information based on the protect ID.

• Grammar

  s32 drv_miu_protect_status(u8 index);
  

• Parameter

  Parameter name	Description	Input/Output
  index	protect id	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.2.10 drv_miu_protect_address

• Function

  Retrieve the protection address information based on the protect ID

• Grammar

  u16* drv_miu_protect_address(u8 index, ss_phys_addr_t *start, ss_phys_addr_t *end);
  

• Parameter

  Parameter name	Description	Input/Output
  index	protect id	Input
  start	start address	Output
  end	end address	Output

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.2.11 drv_miu_protect_set_panic

• Function

  Enable or disable panic when protection is triggered.

• Grammar

  void drv_miu_protect_set_panic(u8 enable);
  

• Parameter

  Parameter name	Description	Input/Output
  enable	switch control	Input

• Return Value

  • void

• Rely

  • Header Files: drv_miu.h

5.3. MMU Function Section

5.3.1 drv_miu_mmu_set_page_size

• Function

  Configure the MMU page size.

• Grammar

  s32 drv_miu_mmu_set_page_size(u8 page_mode);
  

• Parameter

  Parameter name	Description	Input/Output
  page_mode	page size	Input

  page_mode: MMU_PAGE_SIZE_32K/MMU_PAGE_SIZE_64K/MMU_PAGE_SIZE_128K

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.3.2 drv_miu_mmu_get_page_size

• Function

  Get the MMU page size.

• Grammar

  u32 drv_miu_mmu_get_page_size(void);
  

• Parameter

  • void

• Return Value

  • failure: 0

  • success: Return the current page size

• Rely

  • Header Files: drv_miu.h

5.3.3 drv_miu_mmu_set_region

• Function

  Establish a mapping relationship between VPA (Virtual Physical Address) regions and PA (Physical Address) regions.

• Grammar

  s32 drv_miu_mmu_set_region(u16 vpa_region, u16 pa_region);
  

• Parameter

  Parameter name	Description	Input/Output
  vpa_region	vpa region id	Input
  pa_region	pa region id	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.3.4 drv_miu_mmu_map_entry

• Function

  Establish a mapping relationship between VPA (Virtual Physical Address) entries and PA (Physical Address) entries.

• Grammar

  s32 drv_miu_mmu_map_entry(u16 vpa_entry, u16 pa_entry);
  

• Parameter

  Parameter name	Description	Input/Output
  vpa_entry	vpa entry id	Input
  pa_entry	pa entry id	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.3.5 drv_miu_mmu_unmap_entry

• Function

  Remove the mapping relationship between VPA (Virtual Physical Address) entries and PA (Physical Address) entries.

• Grammar

  s32 drv_miu_mmu_unmap_entry(u16 vpa_entry);
  

• Parameter

  Parameter name	Description	Input/Output
  vpa_entry	vpa entry id	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.3.6 drv_miu_mmu_query_entry

• Function

  Obtain the PA (Physical Address) entry id corresponding to the current VPA (Virtual Physical Address) entry.

• Grammar

  u16 drv_miu_mmu_query_entry(u16 vpa_entry);
  

• Parameter

  Parameter name	Description	Input/Output
  vpa_entry	vpa entry id	Input

• Return Value

  • return pa entry id

• Rely

  • Header Files: drv_miu.h

5.3.7 drv_miu_mmu_enable

• Function

  Enable or disable MMU functionality.

• Grammar

  s32 drv_miu_mmu_enable(u8 enable);
  

• Parameter

  Parameter name	Description	Input/Output
  enable	Switch control	Input

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.3.8 drv_miu_mmu_reset

• Function

  Reset the MMU.

• Grammar

  s32 drv_miu_mmu_reset(void);
  

• Parameter

  • void

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.3.9 drv_mmu_callback_func

• Function

  Enable or disable MMU functionality.

• Grammar

  void drv_mmu_callback_func(drv_mmu_irq_callback func);
  

• Parameter

  Parameter name	Description	Input/Output
  func	Used to describe callback function	Input

• Return Value

  • void

• Rely

  • Header Files: drv_miu.h

5.4. Misc Function Section

5.4.1 drv_miu_dram_info

• Function

  Obtain the parameter information of the currently used DRAM.

• Grammar

  s32 drv_miu_dram_info(struct miu_dram_info* dram);
  

• Parameter

  Parameter name	Description	Input/Output
  dram	dram parameter info	Output

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.4.2 drv_miu_init

• Function

  Initialize the MIU.

• Grammar

  s32 drv_miu_init(void);
  

• Parameter

  • void

• Return Value

  • 0: success

  • Non-zero: failure

• Rely

  • Header Files: drv_miu.h

5.4.3 drv_miu_phy_to_miu

• Function

  Conversion from physical address to MIU address.

• Grammar

  ss_miu_addr_t drv_miu_phy_to_miu(ss_phys_addr_t phy_addr);
  

• Parameter

  Parameter name	Description	Input/Output
  phy_addr	physical address	Input

• Return Value

  • MIU address

• Rely

  • Header Files: drv_miu.h

5.4.4 drv_miu_addr_to_phy

• Function

  Conversion from MIU address to physical address.

• Grammar

  ss_phys_addr_t drv_miu_addr_to_phy(ss_miu_addr_t miu_addr);
  

• Parameter

  Parameter name	Description	Input/Output
  miu_addr	MIU address	Input

• Return Value

  • physical address

• Rely

  • Header Files: drv_miu.h

5.5 data structure description

• Illustrate

  Define DRAM-related parameter information.

• Definition

  struct miu_dram_info
  {
      u64 size;
      u32 dram_freq;
      u32 miupll_freq;
      u8  type;
      u8  data_rate;
      u8  bus_width;
      u8  ssc;
  };
  

• Member

  Member Name	Description
  size	The size of the DRAM, measured in MB
  dram_freq	The frequency of the DRAM, measured in MHz
  miupll_freq	The frequency of the miupll, measured in MHz
  type	The type of DRAM, such as DDR3 or DDR4
  data_rate	The transmission mode, which can be 4x mode or 8x mode
  bus_width	The transmission bit width, which can be 16 bit, 32 bit, or 64 bit
  ssc	Whether spread spectrum is enabled

6. FAQ

6.1 Check the current bandwidth usage

1. Use cat /sys/devices/system/miu/miu0/dram_info to view information related to DDR chips.

2. Use cat /sys/devices/system/miu/miu0/bw to check the corresponding usage status.

6.2 Check the current protection configuration information

It can be viewed through cat /proc/mi_modules/mi_sys_mma/miu_protect.