spi: spi-zynqmp-gqspi: add mutex locking for exec_op

The spi-mem framework has no locking to prevent ctlr->mem_ops->exec_op
from concurrency. So add the locking to zynqmp_qspi_exec_op.

Fixes: 1c26372e ("spi: spi-zynqmp-gqspi: Update driver to use spi-mem framework")
Signed-off-by: Quanyang Wang <quanyang.wang@windriver.com>
Reviewed-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@xilinx.com>
Link: https://lore.kernel.org/r/20210408040223.23134-3-quanyang.wang@windriver.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-zynqmp-gqspi.c

@@ -173,6 +173,7 @@ struct zynqmp_qspi {
 	u32 genfifoentry;
 	enum mode_type mode;
 	struct completion data_completion;
+	struct mutex op_lock;
 };
 
 /**
@@ -951,6 +952,7 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
 		op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
 		op->dummy.buswidth, op->data.buswidth);
 
+	mutex_lock(&xqspi->op_lock);
 	zynqmp_qspi_config_op(xqspi, mem->spi);
 	zynqmp_qspi_chipselect(mem->spi, false);
 	genfifoentry |= xqspi->genfifocs;
@@ -1084,6 +1086,7 @@ static int zynqmp_qspi_exec_op(struct spi_mem *mem,
 return_err:
 
 	zynqmp_qspi_chipselect(mem->spi, true);
+	mutex_unlock(&xqspi->op_lock);
 
 	return err;
 }
@@ -1156,6 +1159,8 @@ static int zynqmp_qspi_probe(struct platform_device *pdev)
 		goto clk_dis_pclk;
 	}
 
+	mutex_init(&xqspi->op_lock);
+
 	pm_runtime_use_autosuspend(&pdev->dev);
 	pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
 	pm_runtime_set_active(&pdev->dev);