[PATCH v8 04/10] hw/ssi: imx_spi: Rework imx_spi_reset() to keep CONREG register value

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

From: Philippe Mathieu-Daudé <f4bug@amsat.org>

When the block is disabled, all registers are reset with the
exception of the ECSPI_CONREG. It is initialized to zero
when the instance is created.

Ref: i.MX 6DQ Applications Processor Reference Manual (IMX6DQRM),
     chapter 21.7.3: Control Register (ECSPIx_CONREG)

Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20210115153049.3353008-4-f4bug@amsat.org>
Reviewed-by: Bin Meng <bin.meng@windriver.com>
Signed-off-by: Bin Meng <bin.meng@windriver.com>

---

(no changes since v7)

Changes in v7:
- remove the RFC tag

Changes in v6:
- new patch: [RFC] rework imx_spi_reset() to keep CONREG register value

 hw/ssi/imx_spi.c | 17 ++++++++++++++---
 1 file changed, 14 insertions(+), 3 deletions(-)

diff --git a/hw/ssi/imx_spi.c b/hw/ssi/imx_spi.c
index 8fb3c9b..c952a3d 100644
--- a/hw/ssi/imx_spi.c
+++ b/hw/ssi/imx_spi.c
@@ -231,12 +231,23 @@ static void imx_spi_flush_txfifo(IMXSPIState *s)
 static void imx_spi_reset(DeviceState *dev)
 {
     IMXSPIState *s = IMX_SPI(dev);
+    int i;
 
     DPRINTF("\n");
 
-    memset(s->regs, 0, sizeof(s->regs));
-
-    s->regs[ECSPI_STATREG] = 0x00000003;
+    for (i = 0; i < ARRAY_SIZE(s->regs); i++) {
+        switch (i) {
+        case ECSPI_CONREG:
+            /* CONREG is not updated on reset */
+            break;
+        case ECSPI_STATREG:
+            s->regs[i] = 0x00000003;
+            break;
+        default:
+            s->regs[i] = 0;
+            break;
+        }
+    }
 
     imx_spi_rxfifo_reset(s);
     imx_spi_txfifo_reset(s);
-- 
2.7.4