[i.MX] fix CS handling during SPI access.

Commit Message

Jean-Christophe Dubois Jan. 2, 2017, 8:55 p.m. UTC

The i.MX SPI device was not de-asserting the CS line at the end of
memory access.

This triggered a SIGSEGV in Qemu when the sabrelite emulator was acessing
a SPI flash memory.

Whit this path the CS signal is correctly asserted and deasserted arround
memory access.

This was tested by:
* booting linux on Sabrelite Qemu emulator.
* booting xvisor on Sabrelite Qemu emultor.

Signed-off-by: Jean-Christophe Dubois <[e-mail]>
---
 hw/ssi/imx_spi.c | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

Comments

[e-mail] Jan. 2, 2017, 8:59 p.m. UTC | #1

Hi,

Your series seems to have some coding style problems. See output below for
more information:

Subject: [Qemu-devel] [PATCH] [i.MX] fix CS handling during SPI access.
Message-id: [e-mail]
Type: series

=== TEST SCRIPT BEGIN ===
#!/bin/bash

BASE=base
n=1
total=$(git log --oneline $BASE.. | wc -l)
failed=0

# Useful git options
git config --local diff.renamelimit 0
git config --local diff.renames True

commits="$(git log --format=%H --reverse $BASE..)"
for c in $commits; do
    echo "Checking PATCH $n/$total: $(git log -n 1 --format=%s $c)..."
    if ! git show $c --format=email | ./scripts/checkpatch.pl --mailback -; then
        failed=1
        echo
    fi
    n=$((n+1))
done

exit $failed
=== TEST SCRIPT END ===

Updating 3c8cf5a9c21ff8782164d1def7f44bd888713384
From https://github.com/patchew-project/qemu
 * [new tag]         patchew/[e-mail] -> patchew/[e-mail]
Switched to a new branch 'test'
3d25a87 fix CS handling during SPI access.

=== OUTPUT BEGIN ===
Checking PATCH 1/1: fix CS handling during SPI access....
ERROR: suspect code indent for conditional statements (4, 7)
#86: FILE: hw/ssi/imx_spi.c:261:
+    for (i = 0; i < 4; i++) {
+       qemu_set_irq(s->cs_lines[i], 1);

total: 1 errors, 0 warnings, 76 lines checked

Your patch has style problems, please review.  If any of these errors
are false positives report them to the maintainer, see
CHECKPATCH in MAINTAINERS.

=== OUTPUT END ===

Test command exited with code: 1


---
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Please send your feedback to [e-mail]

Patch

diff --git a/hw/ssi/imx_spi.c b/hw/ssi/imx_spi.c
index e4e395f..c2d293c 100644
--- a/hw/ssi/imx_spi.c
+++ b/hw/ssi/imx_spi.c
@@ -152,13 +152,20 @@  static bool imx_spi_is_multiple_master_burst(IMXSPIState *s)
 
 static void imx_spi_flush_txfifo(IMXSPIState *s)
 {
-    uint32_t tx;
-    uint32_t rx;
+    uint32_t i;
 
     DPRINTF("Begin: TX Fifo Size = %d, RX Fifo Size = %d\n",
             fifo32_num_used(&s->tx_fifo), fifo32_num_used(&s->rx_fifo));
 
+    /* Activate the requested CS line */
+    for (i = 0; i < 4; i++) {
+        qemu_set_irq(s->cs_lines[i],
+                     i == imx_spi_selected_channel(s) ? 0 : 1);
+    }
+
     while (!fifo32_is_empty(&s->tx_fifo)) {
+        uint32_t tx;
+        uint32_t rx = 0;
         int tx_burst = 0;
         int index = 0;
 
@@ -178,8 +185,6 @@  static void imx_spi_flush_txfifo(IMXSPIState *s)
 
         tx_burst = MIN(s->burst_length, 32);
 
-        rx = 0;
-
         while (tx_burst) {
             uint8_t byte = tx & 0xff;
 
@@ -221,6 +226,13 @@  static void imx_spi_flush_txfifo(IMXSPIState *s)
         s->regs[ECSPI_STATREG] |= ECSPI_STATREG_TC;
     }
 
+    /* Deselect all SS lines if transfert if completed */
+    if (s->regs[ECSPI_STATREG] & ECSPI_STATREG_TC) {
+        for (i = 0; i < 4; i++) {
+            qemu_set_irq(s->cs_lines[i], 1);
+        }
+    }
+
     /* TODO: We should also use TDR and RDR bits */
 
     DPRINTF("End: TX Fifo Size = %d, RX Fifo Size = %d\n",
@@ -230,6 +242,7 @@  static void imx_spi_flush_txfifo(IMXSPIState *s)
 static void imx_spi_reset(DeviceState *dev)
 {
     IMXSPIState *s = IMX_SPI(dev);
+    uint32_t i;
 
     DPRINTF("\n");
 
@@ -243,6 +256,11 @@  static void imx_spi_reset(DeviceState *dev)
     imx_spi_update_irq(s);
 
     s->burst_length = 0;
+
+    /* Disable all CS lines */
+    for (i = 0; i < 4; i++) {
+       qemu_set_irq(s->cs_lines[i], 1);
+    }
 }
 
 static uint64_t imx_spi_read(void *opaque, hwaddr offset, unsigned size)
@@ -359,15 +377,8 @@  static void imx_spi_write(void *opaque, hwaddr offset, uint64_t value,
         }
 
         if (imx_spi_channel_is_master(s)) {
-            int i;
-
             /* We are in master mode */
 
-            for (i = 0; i < 4; i++) {
-                qemu_set_irq(s->cs_lines[i],
-                             i == imx_spi_selected_channel(s) ? 0 : 1);
-            }
-
             if ((value & change_mask & ECSPI_CONREG_SMC) &&
                 !fifo32_is_empty(&s->tx_fifo)) {
                 /* SMC bit is set and TX FIFO has some slots filled in */