[PATCH v5 4/6] hw/ssi: imx_spi: Round up the burst length to be multiple of 8

[Bin Meng <bmeng.cn@gmail.com>]

From: Bin Meng <bin.meng@windriver.com>

Current implementation of the imx spi controller expects the burst
length to be multiple of 8, which is the most common use case.

In case the burst length is not what we expect, log it to give user
a chance to notice it, and round it up to be multiple of 8.

Signed-off-by: Bin Meng <bin.meng@windriver.com>

---

Changes in v5:
- round up the burst length to be multiple of 8

Changes in v4:
- s/normal/common/ in the commit message
- log the burst length value in the log message

Changes in v3:
- new patch: log unimplemented burst length

 hw/ssi/imx_spi.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/hw/ssi/imx_spi.c b/hw/ssi/imx_spi.c
index 880939f595..b7456de065 100644
--- a/hw/ssi/imx_spi.c
+++ b/hw/ssi/imx_spi.c
@@ -128,7 +128,20 @@ static uint8_t imx_spi_selected_channel(IMXSPIState *s)
 
 static uint32_t imx_spi_burst_length(IMXSPIState *s)
 {
-    return EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_BURST_LENGTH) + 1;
+    uint32_t burst;
+
+    burst = EXTRACT(s->regs[ECSPI_CONREG], ECSPI_CONREG_BURST_LENGTH) + 1;
+    if (burst % 8) {
+        qemu_log_mask(LOG_UNIMP,
+                      "[%s]%s: burst length (%d) not multiple of 8!\n",
+                      TYPE_IMX_SPI, __func__, burst);
+        burst = ROUND_UP(burst, 8);
+        qemu_log_mask(LOG_UNIMP,
+                      "[%s]%s: burst length rounded up to %d; this may not work.\n",
+                      TYPE_IMX_SPI, __func__, burst);
+    }
+
+    return burst;
 }
 
 static bool imx_spi_is_enabled(IMXSPIState *s)
-- 
2.25.1