--- /dev/null
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * OPEN Alliance 10BASE‑T1x MAC‑PHY Serial Interface framework
+ *
+ * Author: Parthiban Veerasooran <parthiban.veerasooran@microchip.com>
+ */
+
+#include <linux/bitfield.h>
+#include <linux/oa_tc6.h>
+
+/* Control command header */
+#define OA_TC6_CTRL_HEADER_DATA_NOT_CTRL BIT(31)
+#define OA_TC6_CTRL_HEADER_WRITE_NOT_READ BIT(29)
+#define OA_TC6_CTRL_HEADER_MEM_MAP_SELECTOR GENMASK(27, 24)
+#define OA_TC6_CTRL_HEADER_ADDR GENMASK(23, 8)
+#define OA_TC6_CTRL_HEADER_LENGTH GENMASK(7, 1)
+#define OA_TC6_CTRL_HEADER_PARITY BIT(0)
+
+#define OA_TC6_CTRL_HEADER_SIZE 4
+#define OA_TC6_CTRL_REG_VALUE_SIZE 4
+#define OA_TC6_CTRL_IGNORED_SIZE 4
+#define OA_TC6_CTRL_MAX_REGISTERS 128
+#define OA_TC6_CTRL_SPI_BUF_SIZE (OA_TC6_CTRL_HEADER_SIZE +\
+ (OA_TC6_CTRL_MAX_REGISTERS *\
+ OA_TC6_CTRL_REG_VALUE_SIZE) +\
+ OA_TC6_CTRL_IGNORED_SIZE)
+
+/* Internal structure for MAC-PHY drivers */
+struct oa_tc6 {
+ struct spi_device *spi;
+ struct mutex spi_ctrl_lock; /* Protects spi control transfer */
+ void *spi_ctrl_tx_buf;
+ void *spi_ctrl_rx_buf;
+};
+
+enum oa_tc6_header_type {
+ OA_TC6_CTRL_HEADER,
+};
+
+enum oa_tc6_register_op {
+ OA_TC6_CTRL_REG_WRITE = 1,
+};
+
+static int oa_tc6_spi_transfer(struct oa_tc6 *tc6,
+ enum oa_tc6_header_type header_type, u16 length)
+{
+ struct spi_transfer xfer = { 0 };
+ struct spi_message msg;
+
+ xfer.tx_buf = tc6->spi_ctrl_tx_buf;
+ xfer.rx_buf = tc6->spi_ctrl_rx_buf;
+ xfer.len = length;
+
+ spi_message_init(&msg);
+ spi_message_add_tail(&xfer, &msg);
+
+ return spi_sync(tc6->spi, &msg);
+}
+
+static int oa_tc6_get_parity(u32 p)
+{
+ /* Public domain code snippet, lifted from
+ * http://www-graphics.stanford.edu/~seander/bithacks.html
+ */
+ p ^= p >> 1;
+ p ^= p >> 2;
+ p = (p & 0x11111111U) * 0x11111111U;
+
+ /* Odd parity is used here */
+ return !((p >> 28) & 1);
+}
+
+static __be32 oa_tc6_prepare_ctrl_header(u32 addr, u8 length,
+ enum oa_tc6_register_op reg_op)
+{
+ u32 header;
+
+ header = FIELD_PREP(OA_TC6_CTRL_HEADER_DATA_NOT_CTRL,
+ OA_TC6_CTRL_HEADER) |
+ FIELD_PREP(OA_TC6_CTRL_HEADER_WRITE_NOT_READ, reg_op) |
+ FIELD_PREP(OA_TC6_CTRL_HEADER_MEM_MAP_SELECTOR, addr >> 16) |
+ FIELD_PREP(OA_TC6_CTRL_HEADER_ADDR, addr) |
+ FIELD_PREP(OA_TC6_CTRL_HEADER_LENGTH, length - 1);
+ header |= FIELD_PREP(OA_TC6_CTRL_HEADER_PARITY,
+ oa_tc6_get_parity(header));
+
+ return cpu_to_be32(header);
+}
+
+static void oa_tc6_update_ctrl_write_data(struct oa_tc6 *tc6, u32 value[],
+ u8 length)
+{
+ __be32 *tx_buf = tc6->spi_ctrl_tx_buf + OA_TC6_CTRL_HEADER_SIZE;
+
+ for (int i = 0; i < length; i++)
+ *tx_buf++ = cpu_to_be32(value[i]);
+}
+
+static u16 oa_tc6_calculate_ctrl_buf_size(u8 length)
+{
+ /* Control command consists 4 bytes header + 4 bytes register value for
+ * each register + 4 bytes ignored value.
+ */
+ return OA_TC6_CTRL_HEADER_SIZE + OA_TC6_CTRL_REG_VALUE_SIZE * length +
+ OA_TC6_CTRL_IGNORED_SIZE;
+}
+
+static void oa_tc6_prepare_ctrl_spi_buf(struct oa_tc6 *tc6, u32 address,
+ u32 value[], u8 length,
+ enum oa_tc6_register_op reg_op)
+{
+ __be32 *tx_buf = tc6->spi_ctrl_tx_buf;
+
+ *tx_buf = oa_tc6_prepare_ctrl_header(address, length, reg_op);
+
+ oa_tc6_update_ctrl_write_data(tc6, value, length);
+}
+
+static int oa_tc6_check_ctrl_write_reply(struct oa_tc6 *tc6, u8 size)
+{
+ u8 *tx_buf = tc6->spi_ctrl_tx_buf;
+ u8 *rx_buf = tc6->spi_ctrl_rx_buf;
+
+ rx_buf += OA_TC6_CTRL_IGNORED_SIZE;
+
+ /* The echoed control write must match with the one that was
+ * transmitted.
+ */
+ if (memcmp(tx_buf, rx_buf, size - OA_TC6_CTRL_IGNORED_SIZE))
+ return -EPROTO;
+
+ return 0;
+}
+
+static int oa_tc6_perform_ctrl(struct oa_tc6 *tc6, u32 address, u32 value[],
+ u8 length, enum oa_tc6_register_op reg_op)
+{
+ u16 size;
+ int ret;
+
+ /* Prepare control command and copy to SPI control buffer */
+ oa_tc6_prepare_ctrl_spi_buf(tc6, address, value, length, reg_op);
+
+ size = oa_tc6_calculate_ctrl_buf_size(length);
+
+ /* Perform SPI transfer */
+ ret = oa_tc6_spi_transfer(tc6, OA_TC6_CTRL_HEADER, size);
+ if (ret) {
+ dev_err(&tc6->spi->dev, "SPI transfer failed for control: %d\n",
+ ret);
+ return ret;
+ }
+
+ /* Check echoed/received control write command reply for errors */
+ return oa_tc6_check_ctrl_write_reply(tc6, size);
+}
+
+/**
+ * oa_tc6_write_registers - function for writing multiple consecutive registers.
+ * @tc6: oa_tc6 struct.
+ * @address: address of the first register to be written in the MAC-PHY.
+ * @value: values to be written from the starting register address @address.
+ * @length: number of consecutive registers to be written from @address.
+ *
+ * Maximum of 128 consecutive registers can be written starting at @address.
+ *
+ * Return: 0 on success otherwise failed.
+ */
+int oa_tc6_write_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_WRITE);
+ mutex_unlock(&tc6->spi_ctrl_lock);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(oa_tc6_write_registers);
+
+/**
+ * oa_tc6_write_register - function for writing a MAC-PHY register.
+ * @tc6: oa_tc6 struct.
+ * @address: register address of the MAC-PHY to be written.
+ * @value: value to be written in the @address register address of the MAC-PHY.
+ *
+ * Return: 0 on success otherwise failed.
+ */
+int oa_tc6_write_register(struct oa_tc6 *tc6, u32 address, u32 value)
+{
+ return oa_tc6_write_registers(tc6, address, &value, 1);
+}
+EXPORT_SYMBOL_GPL(oa_tc6_write_register);
+
+/**
+ * oa_tc6_init - allocates and initializes oa_tc6 structure.
+ * @spi: device with which data will be exchanged.
+ *
+ * Return: pointer reference to the oa_tc6 structure if the MAC-PHY
+ * initialization is successful otherwise NULL.
+ */
+struct oa_tc6 *oa_tc6_init(struct spi_device *spi)
+{
+ struct oa_tc6 *tc6;
+
+ tc6 = devm_kzalloc(&spi->dev, sizeof(*tc6), GFP_KERNEL);
+ if (!tc6)
+ return NULL;
+
+ tc6->spi = spi;
+ mutex_init(&tc6->spi_ctrl_lock);
+
+ /* Set the SPI controller to pump at realtime priority */
+ tc6->spi->rt = true;
+ spi_setup(tc6->spi);
+
+ tc6->spi_ctrl_tx_buf = devm_kzalloc(&tc6->spi->dev,
+ OA_TC6_CTRL_SPI_BUF_SIZE,
+ GFP_KERNEL);
+ if (!tc6->spi_ctrl_tx_buf)
+ return NULL;
+
+ tc6->spi_ctrl_rx_buf = devm_kzalloc(&tc6->spi->dev,
+ OA_TC6_CTRL_SPI_BUF_SIZE,
+ GFP_KERNEL);
+ if (!tc6->spi_ctrl_rx_buf)
+ return NULL;
+
+ return tc6;
+}
+EXPORT_SYMBOL_GPL(oa_tc6_init);
+
+MODULE_DESCRIPTION("OPEN Alliance 10BASE‑T1x MAC‑PHY Serial Interface Lib");
+MODULE_AUTHOR("Parthiban Veerasooran <parthiban.veerasooran@microchip.com>");
+MODULE_LICENSE("GPL");
projects / linux.git / commitdiff