wilc1000: add reset/terminate/repeat command support for SPI bus

Add reset/terminate/repeat command for SPI module. In case of SPI commands
failure, the host should issue a RESET command to WILC chip to recover
from any temporary bus error.
For now, the new command support is added and later the SPI read/write
API's would be modified to make use of these commands for retry mechanism
Signed-off-by: Ajay Singh <ajay.kathat@microchip.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
Link: https://lore.kernel.org/r/20210916164902.74629-6-ajay.kathat@microchip.com

drivers/net/wireless/microchip/wilc1000/spi.c

@@ -144,6 +144,12 @@ struct wilc_spi_rsp_data {
 	u8 data[];
 } __packed;
 
+struct wilc_spi_special_cmd_rsp {
+	u8 skip_byte;
+	u8 rsp_cmd_type;
+	u8 status;
+} __packed;
+
 static int wilc_bus_probe(struct spi_device *spi)
 {
 	int ret;
@@ -709,6 +715,61 @@ static int wilc_spi_dma_rw(struct wilc *wilc, u8 cmd, u32 adr, u8 *b, u32 sz)
 	return 0;
 }
 
+static int wilc_spi_special_cmd(struct wilc *wilc, u8 cmd)
+{
+	struct spi_device *spi = to_spi_device(wilc->dev);
+	struct wilc_spi *spi_priv = wilc->bus_data;
+	u8 wb[32], rb[32];
+	int cmd_len, resp_len = 0;
+	struct wilc_spi_cmd *c;
+	struct wilc_spi_special_cmd_rsp *r;
+
+	if (cmd != CMD_TERMINATE && cmd != CMD_REPEAT && cmd != CMD_RESET)
+		return -EINVAL;
+
+	memset(wb, 0x0, sizeof(wb));
+	memset(rb, 0x0, sizeof(rb));
+	c = (struct wilc_spi_cmd *)wb;
+	c->cmd_type = cmd;
+
+	if (cmd == CMD_RESET)
+		memset(c->u.simple_cmd.addr, 0xFF, 3);
+
+	cmd_len = offsetof(struct wilc_spi_cmd, u.simple_cmd.crc);
+	resp_len = sizeof(*r);
+
+	if (spi_priv->crc7_enabled) {
+		c->u.simple_cmd.crc[0] = wilc_get_crc7(wb, cmd_len);
+		cmd_len += 1;
+	}
+	if (cmd_len + resp_len > ARRAY_SIZE(wb)) {
+		dev_err(&spi->dev, "spi buffer size too small (%d) (%d) (%zu)\n",
+			cmd_len, resp_len, ARRAY_SIZE(wb));
+		return -EINVAL;
+	}
+
+	if (wilc_spi_tx_rx(wilc, wb, rb, cmd_len + resp_len)) {
+		dev_err(&spi->dev, "Failed cmd write, bus error...\n");
+		return -EINVAL;
+	}
+
+	r = (struct wilc_spi_special_cmd_rsp *)&rb[cmd_len];
+	if (r->rsp_cmd_type != cmd) {
+		if (!spi_priv->probing_crc)
+			dev_err(&spi->dev,
+				"Failed cmd response, cmd (%02x), resp (%02x)\n",
+				cmd, r->rsp_cmd_type);
+		return -EINVAL;
+	}
+
+	if (r->status != WILC_SPI_COMMAND_STAT_SUCCESS) {
+		dev_err(&spi->dev, "Failed cmd state response state (%02x)\n",
+			r->status);
+		return -EINVAL;
+	}
+	return 0;
+}
+
 static int wilc_spi_read_reg(struct wilc *wilc, u32 addr, u32 *data)
 {
 	struct spi_device *spi = to_spi_device(wilc->dev);