[Qemu-devel] [PATCH v4] sam460ex: Fix sam460ex device tree when booting the Linux kernel

* [Qemu-devel] [PATCH v4] sam460ex: Fix sam460ex device tree when booting the Linux kernel
@ 2018-06-23 21:18 Guenter Roeck
  2018-06-23 21:22 ` BALATON Zoltan
  2018-06-24 10:12 ` David Gibson
  0 siblings, 2 replies; 3+ messages in thread
From: Guenter Roeck @ 2018-06-23 21:18 UTC (permalink / raw)
  To: David Gibson
  Cc: Alexander Graf, qemu-ppc, qemu-devel, BALATON Zoltan, Guenter Roeck

sam460ex (or at least this emulation) does not support the "ibm,cpm" power
management. As a result, Linux crashes when trying to access it. Remove
its device tree node. Also, if/when we boot the Linux kernel directly,
serial port clock frequencies in the device tree file will be unset, and
serial port initialization will fail. Add valid frequency values to
the serial ports to be able to use it. Also set valid values for the other
clock nodes otherwise set by u-boot.

Signed-off-by: Guenter Roeck <linux@roeck-us.net>
---
v4: Use correct UART clock.
v3: Fix style problems (ERROR: braces {} are necessary for all arms ...).
    Use defines for clock frequencies.
    Use clock frequencies as reported by u-boot in real system.
    Use more specific prefix in subject.
    Fix typos in description.
v2: Initialize all serial nodes to match u-boot behavior more closely.
    Use direct fdt API functions and ignore errors when clearing out
    /cpm and for setting the serial port clocks.

 hw/ppc/sam460ex.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/hw/ppc/sam460ex.c b/hw/ppc/sam460ex.c
index bdc53d2..33ea518 100644
--- a/hw/ppc/sam460ex.c
+++ b/hw/ppc/sam460ex.c
@@ -37,6 +37,8 @@
 #include "hw/i2c/smbus.h"
 #include "hw/usb/hcd-ehci.h"
 
+#include <libfdt.h>
+
 #define BINARY_DEVICE_TREE_FILE "canyonlands.dtb"
 #define UBOOT_FILENAME "u-boot-sam460-20100605.bin"
 /* to extract the official U-Boot bin from the updater: */
@@ -67,6 +69,10 @@
 */
 
 #define CPU_FREQ 1150000000
+#define PLB_FREQ 230000000
+#define OPB_FREQ 115000000
+#define EBC_FREQ 115000000
+#define UART_FREQ 11059200
 #define SDRAM_NR_BANKS 4
 
 /* FIXME: See u-boot.git 8ac41e, also fix in ppc440_uc.c */
@@ -255,6 +261,7 @@ static int sam460ex_load_device_tree(hwaddr addr,
     void *fdt;
     uint32_t tb_freq = CPU_FREQ;
     uint32_t clock_freq = CPU_FREQ;
+    int offset;
 
     filename = qemu_find_file(QEMU_FILE_TYPE_BIOS, BINARY_DEVICE_TREE_FILE);
     if (!filename) {
@@ -308,6 +315,27 @@ static int sam460ex_load_device_tree(hwaddr addr,
     qemu_fdt_setprop_cell(fdt, "/cpus/cpu@0", "timebase-frequency",
                               tb_freq);
 
+    /* Remove cpm node if it exists (it is not emulated) */
+    offset = fdt_path_offset(fdt, "/cpm");
+    if (offset >= 0) {
+        fdt_nop_node(fdt, offset);
+    }
+
+    /* set serial port clocks */
+    offset = fdt_node_offset_by_compatible(fdt, -1, "ns16550");
+    while (offset >= 0) {
+        fdt_setprop_cell(fdt, offset, "clock-frequency", UART_FREQ);
+        offset = fdt_node_offset_by_compatible(fdt, offset, "ns16550");
+    }
+
+    /* some more clocks */
+    qemu_fdt_setprop_cell(fdt, "/plb", "clock-frequency",
+                              PLB_FREQ);
+    qemu_fdt_setprop_cell(fdt, "/plb/opb", "clock-frequency",
+                              OPB_FREQ);
+    qemu_fdt_setprop_cell(fdt, "/plb/opb/ebc", "clock-frequency",
+                              EBC_FREQ);
+
     rom_add_blob_fixed(BINARY_DEVICE_TREE_FILE, fdt, fdt_size, addr);
     g_free(fdt);
     ret = fdt_size;
-- 
2.7.4

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