Commit 375d1e02 authored by Parthiban Veerasooran's avatar Parthiban Veerasooran Committed by Jakub Kicinski
Browse files

net: ethernet: oa_tc6: implement register read operation 



Implement register read operation according to the control communication
specified in the OPEN Alliance 10BASE-T1x MACPHY Serial Interface
document. Control read commands are used by the SPI host to read
registers within the MAC-PHY. Each control read commands are composed of
a 32 bits control command header.

The MAC-PHY ignores all data from the SPI host following the control
header for the remainder of the control read command. Control read
commands can read either a single register or multiple consecutive
registers. When multiple consecutive registers are read, the address is
automatically post-incremented by the MAC-PHY. Reading any unimplemented
or undefined registers shall return zero.

Reviewed-by: default avatarAndrew Lunn <andrew@lunn.ch>
Signed-off-by: default avatarParthiban Veerasooran <Parthiban.Veerasooran@microchip.com>
Link: https://patch.msgid.link/20240909082514.262942-4-Parthiban.Veerasooran@microchip.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent aa58bec0

drivers/net/ethernet/oa_tc6.c

+82 −2
Original line number Diff line number Diff line
@@ -38,6 +38,7 @@ enum oa_tc6_header_type { 
};



enum oa_tc6_register_op {

	OA_TC6_CTRL_REG_READ = 0,

	OA_TC6_CTRL_REG_WRITE = 1,

};
@@ -113,6 +114,7 @@ static void oa_tc6_prepare_ctrl_spi_buf(struct oa_tc6 *tc6, u32 address, 


	*tx_buf = oa_tc6_prepare_ctrl_header(address, length, reg_op);



	if (reg_op == OA_TC6_CTRL_REG_WRITE)

		oa_tc6_update_ctrl_write_data(tc6, value, length);

}
@@ -132,6 +134,30 @@ static int oa_tc6_check_ctrl_write_reply(struct oa_tc6 *tc6, u8 size) 
	return 0;

}



static int oa_tc6_check_ctrl_read_reply(struct oa_tc6 *tc6, u8 size)

{

	u32 *rx_buf = tc6->spi_ctrl_rx_buf + OA_TC6_CTRL_IGNORED_SIZE;

	u32 *tx_buf = tc6->spi_ctrl_tx_buf;



	/* The echoed control read header must match with the one that was

	 * transmitted.

	 */

	if (*tx_buf != *rx_buf)

		return -EPROTO;



	return 0;

}



static void oa_tc6_copy_ctrl_read_data(struct oa_tc6 *tc6, u32 value[],

				       u8 length)

{

	__be32 *rx_buf = tc6->spi_ctrl_rx_buf + OA_TC6_CTRL_IGNORED_SIZE +

			 OA_TC6_CTRL_HEADER_SIZE;



	for (int i = 0; i < length; i++)

		value[i] = be32_to_cpu(*rx_buf++);

}



static int oa_tc6_perform_ctrl(struct oa_tc6 *tc6, u32 address, u32 value[],

			       u8 length, enum oa_tc6_register_op reg_op)

{
@@ -152,8 +178,62 @@ static int oa_tc6_perform_ctrl(struct oa_tc6 *tc6, u32 address, u32 value[], 
	}



	/* Check echoed/received control write command reply for errors */

	if (reg_op == OA_TC6_CTRL_REG_WRITE)

		return oa_tc6_check_ctrl_write_reply(tc6, size);



	/* Check echoed/received control read command reply for errors */

	ret = oa_tc6_check_ctrl_read_reply(tc6, size);

	if (ret)

		return ret;



	oa_tc6_copy_ctrl_read_data(tc6, value, length);



	return 0;

}



/**

 * oa_tc6_read_registers - function for reading multiple consecutive registers.

 * @tc6: oa_tc6 struct.

 * @address: address of the first register to be read in the MAC-PHY.

 * @value: values to be read from the starting register address @address.

 * @length: number of consecutive registers to be read from @address.

 *

 * Maximum of 128 consecutive registers can be read starting at @address.

 *

 * Return: 0 on success otherwise failed.

 */

int oa_tc6_read_registers(struct oa_tc6 *tc6, u32 address, u32 value[],

			  u8 length)

{

	int ret;



	if (!length || length > OA_TC6_CTRL_MAX_REGISTERS) {

		dev_err(&tc6->spi->dev, "Invalid register length parameter\n");

		return -EINVAL;

	}



	mutex_lock(&tc6->spi_ctrl_lock);

	ret = oa_tc6_perform_ctrl(tc6, address, value, length,

				  OA_TC6_CTRL_REG_READ);

	mutex_unlock(&tc6->spi_ctrl_lock);



	return ret;

}

EXPORT_SYMBOL_GPL(oa_tc6_read_registers);



/**

 * oa_tc6_read_register - function for reading a MAC-PHY register.

 * @tc6: oa_tc6 struct.

 * @address: register address of the MAC-PHY to be read.

 * @value: value read from the @address register address of the MAC-PHY.

 *

 * Return: 0 on success otherwise failed.

 */

int oa_tc6_read_register(struct oa_tc6 *tc6, u32 address, u32 *value)

{

	return oa_tc6_read_registers(tc6, address, value, 1);

}

EXPORT_SYMBOL_GPL(oa_tc6_read_register);



/**

 * oa_tc6_write_registers - function for writing multiple consecutive registers.

include/linux/oa_tc6.h

+3 −0
Original line number Diff line number Diff line
@@ -15,3 +15,6 @@ struct oa_tc6 *oa_tc6_init(struct spi_device *spi); 
int oa_tc6_write_register(struct oa_tc6 *tc6, u32 address, u32 value);

int oa_tc6_write_registers(struct oa_tc6 *tc6, u32 address, u32 value[],

			   u8 length);

int oa_tc6_read_register(struct oa_tc6 *tc6, u32 address, u32 *value);

int oa_tc6_read_registers(struct oa_tc6 *tc6, u32 address, u32 value[],

			  u8 length);