In the Hardware Driver Foundation \(HDF\), the Serial Peripheral Interface \(SPI\) uses the independent service mode for API adaptation. In this mode, each device independently publishes a device service to handle external access requests. After receiving an access request from an API, the device manager extracts the parameters in the request to call the internal method of the target device. In the independent service mode, the service management capabilities of the HDFDeviceManager can be directly used. However, you need to configure a device node for each device, which increases the memory usage.
Serial Peripheral Interface (SPI) is a serial bus specification used for high-speed, full-duplex, and synchronous communication. In the Hardware Driver Foundation (HDF), the SPI module uses the independent service mode for API adaptation. In this mode, each device independently publishes a service to process external access requests. When receiving an access request, the HDF DeviceManager extracts parameters from the request to call the internal APIs of the target device. In the independent service mode, the HDF DeviceManager provides service management capabilities. However, you need to configure a node for each device, which increases memory usage.
**Figure 1** Independent service mode<aname="fig666465313303"></a>
<tdclass="cellrowborder"valign="top"width="25%"headers="mcps1.2.5.1.2 "><pid="p0671913132514"><aname="p0671913132514"></a><aname="p0671913132514"></a><strongid="b19675134258"><aname="b19675134258"></a><aname="b19675134258"></a>cntlr</strong>: structure pointer to the SPI controller at the core layer.</p>
<pid="p192109186258"><aname="p192109186258"></a><aname="p192109186258"></a><strongid="b1921051810258"><aname="b1921051810258"></a><aname="b1921051810258"></a>msg</strong>: structure pointer to the SPI message.</p>
<pid="p6168736173213"><aname="p6168736173213"></a><aname="p6168736173213"></a><strongid="b92627310191"><aname="b92627310191"></a><aname="b92627310191"></a>count</strong>: number of messages. The value is of the uint32_t type.</p>
<tdclass="cellrowborder"valign="top"width="25%"headers="mcps1.2.5.1.2 "><pid="p242632402513"><aname="p242632402513"></a><aname="p242632402513"></a><strongid="b742642452513"><aname="b742642452513"></a><aname="b742642452513"></a>cntlr</strong>: structure pointer to the SPI controller at the core layer.</p>
<pid="p11168163643217"><aname="p11168163643217"></a><aname="p11168163643217"></a><strongid="b1283910558207"><aname="b1283910558207"></a><aname="b1283910558207"></a>cfg</strong>: structure pointer to the SPI attributes.</p>
<tdclass="cellrowborder"valign="top"width="25%"headers="mcps1.2.5.1.2 "><pid="p9698153182520"><aname="p9698153182520"></a><aname="p9698153182520"></a><strongid="b19698131162510"><aname="b19698131162510"></a><aname="b19698131162510"></a>cntlr</strong>: structure pointer to the SPI controller at the core layer.</p>
<pid="p3168936133218"><aname="p3168936133218"></a><aname="p3168936133218"></a><strongid="b11555148182113"><aname="b11555148182113"></a><aname="b11555148182113"></a>cfg</strong>: structure pointer to the SPI attributes.</p>
<tdclass="cellrowborder"valign="top"width="25%"headers="mcps1.2.5.1.2 "><pid="p181697365327"><aname="p181697365327"></a><aname="p181697365327"></a><strongid="b1876822162218"><aname="b1876822162218"></a><aname="b1876822162218"></a>cntlr</strong>: structure pointer to the SPI controller at the core layer. </p>
<tdclass="cellrowborder"valign="top"width="25.019999999999996%"headers="mcps1.2.5.1.4 "><pid="p1116963693218"><aname="p1116963693218"></a><aname="p1116963693218"></a>Enables the SPI.</p>
<tdclass="cellrowborder"valign="top"width="25%"headers="mcps1.2.5.1.2 "><pid="p31691936193210"><aname="p31691936193210"></a><aname="p31691936193210"></a><strongid="b16798152112239"><aname="b16798152112239"></a><aname="b16798152112239"></a>cntlr</strong>: structure pointer to the SPI controller at the core layer. </p>
<tdclass="cellrowborder"valign="top"width="25.019999999999996%"headers="mcps1.2.5.1.4 "><pid="p1169636103220"><aname="p1169636103220"></a><aname="p1169636103220"></a>Disables the SPI.</p>
</td>
</tr>
</tbody>
</table>
## How to Develop<a name="section799667984152909"></a>
**Table 1** Description of the callback functions in SpiCntlrMethod
| Transfer | **cntlr**: structure pointer to the SPI controller at the core layer.<br>**msg**: structure pointer to the SPI message.<br>**count**: number of messages. The value is of the uint32_t type.| HDF_STATUS| Transfers messages.|
| SetCfg | **cntlr**: structure pointer to the SPI controller at the core layer.<br>**cfg**: structure pointer to the SPI attributes.| HDF_STATUS| Sets SPI controller attributes.|
| GetCfg | **cntlr**: structure pointer to the SPI controller at the core layer.<br>**cfg**: structure pointer to the SPI attributes.| HDF_STATUS| Obtains SPI controller attributes.|
| Open | **cntlr**: structure pointer to the SPI controller at the core layer.| HDF_STATUS| Opens an SPI device.|
| Close | **cntlr**: structure pointer to the SPI controller at the core layer.| HDF_STATUS| Closes an SPI device.|
## How to Develop
The SPI module adaptation involves the following steps:
1. Instantiate the driver entry.
- Instantiate the **HdfDriverEntry** structure.
- Call **HDF\_INIT** to register the **HdfDriverEntry** instance with the HDF.
2. Configure attribute files.
- Add the **deviceNode** information to the **device\_info.hcs** file.
-\(Optional\) Add the **spi\_config.hcs** file.
3. Instantiate the SPI controller object.
- Initialize **SpiCntlr**.
- Instantiate **SpiCntlrMethod** in the **SpiCntlr** object.
For details, see [Available APIs](#section752964871810).
4.\(Optional\) Debug the driver.
For new drivers, verify the basic functions, such as the SPI control status and response to interrupts.
## Development Example<a name="section956157227152909"></a>
The following uses **spi\_hi35xx.c** as an example to present the contents that need to be provided by the vendor to implement device functions.
1. Instantiate the driver entry. The driver entry must be a global variable of the **HdfDriverEntry** type \(defined in **hdf\_device\_desc.h**\), and the value of **moduleName** must be the same as that in **device\_info.hcs**. In the HDF, the start address of each **HdfDriverEntry** object of all loaded drivers is collected to form a segment address space similar to an array for the upper layer to invoke.
Generally, HDF calls the **Bind** function and then the **Init** function to load a driver. If **Init** fails to be called, HDF calls **Release** to release driver resources and exit.
- SPI driver entry reference
```
struct HdfDriverEntry g_hdfSpiDevice = {
.moduleVersion = 1,
.moduleName = "HDF_PLATFORM_SPI",// (Mandatory) The value must be the same as that of moduleName in the .hcs file.
.Bind = HdfSpiDeviceBind, // See the Bind function.
.Init = HdfSpiDeviceInit, // See the Init function.
.Release = HdfSpiDeviceRelease, //See the Release function.
};
// Call HDF_INIT to register the driver entry with the HDF.
HDF_INIT(g_hdfSpiDevice);
```
2. Add the **deviceNode** information to the **device\_info.hcs** file and configure the device attributes in the **spi\_config.hcs** file. The **deviceNode** information is related to registration of the driver entry. The device attribute values are closely related to the default values or value ranges of the **SpiCntlr** members at the core layer.
In this example, there is only one SPI controller. If there are multiple SPI controllers, you need to add the **deviceNode** information to the **device\_info** file and add the corresponding device attributes to the **spi\_config** file.
- **device\_info.hcs** configuration reference
```
root {
device_info {
match_attr = "hdf_manager";
platform :: host {
hostName = "platform_host";
priority = 50;
device_spi :: device {// Configure an HDF device node for each SPI controller.
device0 :: deviceNode {
policy = 1;
priority = 60;
permission = 0644;
moduleName = "HDF_PLATFORM_SPI";
serviceName = "HDF_PLATFORM_SPI_0";
deviceMatchAttr = "hisilicon_hi35xx_spi_0";
}
device1 :: deviceNode {
policy = 1;
priority = 60;
permission = 0644;
moduleName = "HDF_PLATFORM_SPI"; // (Mandatory) Driver name, which must be the same as that of moduleName in the driver entry structure.
serviceName = "HDF_PLATFORM_SPI_1"; // (Mandatory) Unique name of the service published by the driver
deviceMatchAttr = "hisilicon_hi35xx_spi_1";// The value must be the same as that of match_attr in the .hcs file.
}
...
}
}
}
}
```
- **spi\_config.hcs** configuration reference
```
root {
platform {
spi_config {// Configure private data for each SPI controller.
template spi_controller {// Template configuration. In the template, you can configure the common parameters shared by service nodes.
serviceName = "";
match_attr = "";
transferMode = 0; // Data transfer mode, which can be interrupt transfer (0), flow control transfer (1), or DMA transfer (2).
busNum = 0; // Bus number
clkRate = 100000000;
bitsPerWord = 8; // Bit width of the data transferred
mode = 19; // SPI data input/output mode
maxSpeedHz = 0; // Maximum clock frequency
minSpeedHz = 0; // Minimum clock frequency
speed = 2000000; // Current message transfer speed
fifoSize = 256; // FIFO size
numCs = 1; // Chip select (CS) number
regBase = 0x120c0000; // Used for address mapping.
regBase = 0x120c1000; // (Mandatory) Used for address mapping.
irqNum = 101; // (Mandatory) Interrupt number
}
...
//(Optional) Add nodes to the device_info.hcs file as required.
}
}
}
```
3. Initialize the **SpiCntlr** object at the core layer, including initializing the vendor custom structure \(transferring parameters and data\), instantiating **SpiCntlrMethod**\(used to call underlying functions of the driver\) in **SpiCntlr**, and implementing the **HdfDriverEntry** member functions \(**Bind**, **Init**, and **Release**\).
- Custom structure reference
To the driver, the custom structure carries parameters and data. The values in the **spi\_config.hcs** file are read by HDF, and the structure members are initialized through **DeviceResourceIface**. Some important values, such as the device number and bus number, are also passed to the object at the core layer.
```
struct Pl022 {// Corresponds to parameters in .hcs.
struct SpiCntlr *cntlr;
struct DListHead deviceList;
struct OsalSem sem;
volatile unsigned char *phyBase;
volatile unsigned char *regBase;
uint32_t irqNum;
uint32_t busNum;
uint32_t numCs;
uint32_t curCs;
uint32_t speed;
uint32_t fifoSize;
uint32_t clkRate;
uint32_t maxSpeedHz;
uint32_t minSpeedHz;
uint32_t regCrg;
uint32_t clkEnBit;
uint32_t clkRstBit;
uint32_t regMiscCtrl;
uint32_t miscCtrlCsShift;
uint32_t miscCtrlCs;
uint16_t mode;
uint8_t bitsPerWord;
uint8_t transferMode;
};
// SpiCntlr is the core layer controller structure. Its members are assigned with values by using the Init function.
struct SpiCntlr {
struct IDeviceIoService service;
struct HdfDeviceObject *device;
uint32_t busNum;
uint32_t numCs;
uint32_t curCs;
struct OsalMutex lock;
struct SpiCntlrMethod *method;
struct DListHead list;
void *priv;
};
```
- Instantiate the callback function structure **SpiCntlrMethod** in **SpiCntlr**. Other members are initialized by using the **Init** function.
```
// Example in spi_hi35xx.c: instantiate the hook.
struct SpiCntlrMethod g_method = {
.Transfer = Pl022Transfer,
.SetCfg = Pl022SetCfg,
.GetCfg = Pl022GetCfg,
.Open = Pl022Open,
.Close = Pl022Close,
};
```
- Bind function
Input parameters:
**HdfDeviceObject**, an interface parameter exposed by the driver, contains the .hcs configuration file information.
Return values:
HDF\_STATUS
Function description:
Associates the **SpiCntlr** object with **HdfDeviceObject**.
cntlr->device = device; // Enable conversion between HdfDeviceObject and SpiCntlr.
device->service = &(cntlr->service); // Enable conversion between HdfDeviceObject and SpiCntlr.
(void)OsalMutexInit(&cntlr->lock); // Initialize the lock.
DListHeadInit(&cntlr->list); // Add the corresponding node.
cntlr->priv = NULL;
return cntlr;
}
```
- Init function
Input parameters:
**HdfDeviceObject**, an interface parameter exposed by the driver, contains the .hcs configuration file information.
Return values:
HDF\_STATUS \(The following table lists some status. For details about other status, see **HDF\_STATUS** in the **/drivers/framework/include/utils/hdf\_base.h** file.\)
**Table 2** Input parameters and return values of the init function
cntlr = SpiCntlrFromDevice(device);// Forcibly convert HdfDeviceObject to SpiCntlr by using service. For details about the value assignment, see the Bind function.
DListHeadInit(&pl022->deviceList);// Initialize the DList linked list.
pl022->cntlr = cntlr; // Enable conversion between Pl022 and SpiCntlr.
cntlr->priv = pl022; // Enable conversion between Pl022 and SpiCntlr.
cntlr->busNum = pl022->busNum; // Assign a value to busNum in SpiCntlr.
cntlr->method = &g_method; // Connect to the SpiCntlrMethod instance.
...
ret = Pl022CreatAndInitDevice(pl022);
if (ret != 0) {
Pl022Release(pl022); // Release the Pl022 object if the initialization fails.
return ret;
}
return 0;
}
```
- Release function
Input parameters:
**HdfDeviceObject**, an interface parameter exposed by the driver, contains the .hcs configuration file information.
Return values:
–
Function description:
Releases the memory and deletes the controller. This function assigns a value to the **Release** API in the driver entry structure. When the HDF fails to call the **Init** function to initialize the driver, the **Release** function can be called to release driver resources. All forced conversion operations for obtaining the corresponding object can be successful only when the **Init** function has the corresponding value assignment operations.
cntlr = SpiCntlrFromDevice(device);// Forcibly convert HdfDeviceObject to SpiCntlr by using service. For details about the value assignment, see the Bind function.
> For details about the functions in **SpiCntlrMethod**, see [Available APIs](#available-apis).
4. Debug the driver.<br>
(Optional) For new drivers, verify the basic functions, such as the SPI status control and response to interrupts.
## Development Example
The following uses **spi_hi35xx.c** as an example to present the information required for implementing device functions.
1. Instantiate the driver entry.<br/>The driver entry must be a global variable of the **HdfDriverEntry** type (defined in **hdf_device_desc.h**), and the value of **moduleName** must be the same as that in **device_info.hcs**. In the HDF framework, the start address of each **HdfDriverEntry** object of all loaded drivers is collected to form a segment address space similar to an array for the upper layer to invoke.
Generally, the HDF calls the **Bind** function and then the **Init** function to load a driver. If **Init** fails to be called, the HDF calls **Release** to release driver resources and exit.
SPI driver entry example:
```
struct HdfDriverEntry g_hdfSpiDevice = {
.moduleVersion = 1,
.moduleName = "HDF_PLATFORM_SPI",// (Mandatory) The value must be the same as that of moduleName in the .hcs file.
.Bind = HdfSpiDeviceBind, // See the Bind function.
.Init = HdfSpiDeviceInit, // See the Init function.
.Release = HdfSpiDeviceRelease, //See the Release function.
};
// Call HDF_INIT to register the driver entry with the HDF.
HDF_INIT(g_hdfSpiDevice);
```
2. Add the **deviceNode** information to the **device_info.hcs** file and configure the device attributes in the **spi_config.hcs** file.
The **deviceNode** information is related to registration of the driver entry. The device attribute values are closely related to the default values or value ranges of the **SpiCntlr** members at the core layer.
In this example, there is only one SPI controller. If there are multiple SPI controllers, you need to add the **deviceNode** information to the **device_info** file and add the corresponding device attributes to the **spi_config** file for each controller.
-**device_info.hcs** configuration example
```
root {
device_info {
match_attr = "hdf_manager";
platform :: host {
hostName = "platform_host";
priority = 50;
device_spi :: device { // Configure an HDF device node for each SPI controller.
device0 :: deviceNode {
policy = 1;
priority = 60;
permission = 0644;
moduleName = "HDF_PLATFORM_SPI";
serviceName = "HDF_PLATFORM_SPI_0";
deviceMatchAttr = "hisilicon_hi35xx_spi_0";
}
device1 :: deviceNode {
policy = 1;
priority = 60;
permission = 0644;
moduleName = "HDF_PLATFORM_SPI"; // (Mandatory) Driver name, which must be the same as that of moduleName in the driver entry structure.
serviceName = "HDF_PLATFORM_SPI_1"; // (Mandatory) Unique name of the service published by the driver.
deviceMatchAttr = "hisilicon_hi35xx_spi_1";// The value must be the same as that of match_attr in the .hcs file.
}
...
}
}
}
}
```
-**spi_config.hcs** configuration example
```
root {
platform {
spi_config {// Configure private data for each SPI controller.
template spi_controller { // Template configuration. In the template, you can configure the common parameters shared by device nodes.
serviceName = "";
match_attr = "";
transferMode = 0; // Data transfer mode. The value **0** indicates interrupt transfer, **1** indicates flow control transfer, and **2** indicates DMA transfer.
busNum = 0; // Bus number.
clkRate = 100000000;
bitsPerWord = 8 // Number of bits per word.
mode = 19; // SPI data input/output mode.
maxSpeedHz = 0; // Maximum clock frequency.
minSpeedHz = 0; // Minimum clock frequency.
speed = 2000000; // Current message transfer speed.
fifoSize = 256; // FIFO size.
numCs = 1; // Chip select (CS) number.
regBase = 0x120c0000; // Used for address mapping.
regBase = 0x120c1000; // (Mandatory) Used for address mapping.
irqNum = 101; // (Mandatory) IRQ number.
}
...
//(Optional) Add nodes to the device_info.hcs file as required.
}
}
}
```
3. Initialize the **SpiCntlr** object at the core layer, including defining a custom structure (to pass parameters and data) and implementing the **HdfDriverEntry** member functions (**Bind**, **Init**, and **Release**) to instantiate **SpiCntlrMethod** in **SpiCntlr** (so that the underlying driver functions can be called).
- Defining a custom structure
To the driver, the custom structure holds parameters and data. The **DeviceResourceIface** method provided by the HDF reads the values in the **spi_config.hcs** file to initialize the members in the custom structure and passes important parameters, such as the device number and bus number, to the **SpiCntlr** object at the core layer.
```
struct Pl022 {// Corresponds to parameters in .hcs.
struct SpiCntlr *cntlr;
struct DListHead deviceList;
struct OsalSem sem;
volatile unsigned char *phyBase;
volatile unsigned char *regBase;
uint32_t irqNum;
uint32_t busNum;
uint32_t numCs;
uint32_t curCs;
uint32_t speed;
uint32_t fifoSize;
uint32_t clkRate;
uint32_t maxSpeedHz;
uint32_t minSpeedHz;
uint32_t regCrg;
uint32_t clkEnBit;
uint32_t clkRstBit;
uint32_t regMiscCtrl;
uint32_t miscCtrlCsShift;
uint32_t miscCtrlCs;
uint16_t mode;
uint8_t bitsPerWord;
uint8_t transferMode;
};
// SpiCntlr is the core layer controller structure. The Init function assigns values to the members of SpiCntlr.
struct SpiCntlr {
struct IDeviceIoService service;
struct HdfDeviceObject *device;
uint32_t busNum;
uint32_t numCs;
uint32_t curCs;
struct OsalMutex lock;
struct SpiCntlrMethod *method;
struct DListHead list;
void *priv;
};
```
- Instantiating **SpiCntlrMethod** in **SpiCntlr** (other members are initialized by **Init**)
```
// Example in spi_hi35xx.c: instantiate the hooks.
struct SpiCntlrMethod g_method = {
.Transfer = Pl022Transfer,
.SetCfg = Pl022SetCfg,
.GetCfg = Pl022GetCfg,
.Open = Pl022Open,
.Close = Pl022Close,
};
```
-**Bind** function
Input parameter:
**HdfDeviceObject**, an interface parameter exposed by the driver, contains the .hcs information.
Return value:
HDF_STATUS
Function description:
Associates the **SpiCntlr** object with **HdfDeviceObject**.
cntlr = SpiCntlrFromDevice(device); // Use service to forcibly convert HdfDeviceObject to SpiCntlr. For details about the value assignment, see the Bind function.
DListHeadInit(&pl022->deviceList);// Initialize the DList linked list.
pl022->cntlr = cntlr; // Prerequisite for conversion between Pl022 and SpiCntlr.
cntlr->priv = pl022; // Prerequisite for conversion between Pl022 and SpiCntlr.
cntlr->busNum = pl022->busNum; // Assign a value to busNum in SpiCntlr.
cntlr->method = &g_method; // Attach the SpiCntlrMethod instance.
...
ret = Pl022CreatAndInitDevice(pl022);
if (ret != 0) {
Pl022Release(pl022); // Release the Pl022 object if the initialization fails.
return ret;
}
return 0;
}
```
-**Release** function
Input parameter:
**HdfDeviceObject**, an interface parameter exposed by the driver, contains the .hcs information.
Return value:
No value is returned.
Function description:
Releases the memory and deletes the controller. This function assigns values to the **Release** function in the driver entry structure. If the HDF fails to call the **Init** function to initialize the driver, the **Release** function can be called to release driver resources. All forced conversion operations for obtaining the corresponding object can be successful only when the **Init** function has the value assignment operations.
cntlr = SpiCntlrFromDevice(device); // Use service to forcibly convert HdfDeviceObject to SpiCntlr. For details about the value assignment, see the Bind function.
