spi: spi-mem: Adjust op len based on message/transfer size limitations

We need that to adjust the len of the 2nd transfer (called data in
spi-mem) if it's too long to fit in a SPI message or SPI transfer.

Fixes: c36ff266dc82 ("spi: Extend the core to ease integration of SPI memory controllers")
Cc: <stable@vger.kernel.org>
Signed-off-by: Chuanhua Han <chuanhua.han@nxp.com>
Reviewed-by: Boris Brezillon <boris.brezillon@bootlin.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 15 insertions, 0 deletions

diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index e43842c7a31a..eb72dba71d83 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -346,10 +346,25 @@ EXPORT_SYMBOL_GPL(spi_mem_get_name);
 int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op)
 {
         struct spi_controller *ctlr = mem->spi->controller;
+        size_t len;
+
+        len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes;
 
         if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
                 return ctlr->mem_ops->adjust_op_size(mem, op);
 
+        if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) {
+                if (len > spi_max_transfer_size(mem->spi))
+                        return -EINVAL;
+
+                op->data.nbytes = min3((size_t)op->data.nbytes,
+                                       spi_max_transfer_size(mem->spi),
+                                       spi_max_message_size(mem->spi) -
+                                       len);
+                if (!op->data.nbytes)
+                        return -EINVAL;
+        }
+
         return 0;
 }
 EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size);