Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
firmware: google: framebuffer: Tie platform device to PCI hardware
Use the PCI device as parent of the system-framebuffer device instead
of the coreboot device. Prevents SIGBUS or SIGSEG after hot-unplug of
the PCI device while the framebuffer is active.
The simple-framebuffer device depends on the PCI hardware, so this
device needs to be its parent. The current coreboot parent is no
longer needed after the system-framebuffer device has been created.
On systems without PCI or if no PCI parent device could be found,
the platform device hangs on the platform bus directly.
The fix here is similar to code in sysfb, which contained that same
bug.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Tzung-Bi Shih <tzungbi@kernel.org>
Acked-by: Julius Werner <jwerner@chromium.org>
Link: https://patch.msgid.link/20260217155836.96267-5-tzimmermann@suse.de
+77
-5
+77
-5
drivers/firmware/google/framebuffer-coreboot.c
+77
-5
drivers/firmware/google/framebuffer-coreboot.c
···
13
13
#include <linux/kernel.h>
14
14
#include <linux/mm.h>
15
15
#include <linux/module.h>
16
+
#include <linux/pci.h>
16
17
#include <linux/platform_data/simplefb.h>
17
18
#include <linux/platform_device.h>
18
19
#include <linux/sysfb.h>
···
22
21
23
22
#define CB_TAG_FRAMEBUFFER 0x12
24
23
24
+
#if defined(CONFIG_PCI)
25
+
static bool framebuffer_pci_dev_is_enabled(struct pci_dev *pdev)
26
+
{
27
+
/*
28
+
* TODO: Try to integrate this code into the PCI subsystem
29
+
*/
30
+
int ret;
31
+
u16 command;
32
+
33
+
ret = pci_read_config_word(pdev, PCI_COMMAND, &command);
34
+
if (ret != PCIBIOS_SUCCESSFUL)
35
+
return false;
36
+
if (!(command & PCI_COMMAND_MEMORY))
37
+
return false;
38
+
return true;
39
+
}
40
+
41
+
static struct pci_dev *framebuffer_parent_pci_dev(struct resource *res)
42
+
{
43
+
struct pci_dev *pdev = NULL;
44
+
const struct resource *r = NULL;
45
+
46
+
while (!r && (pdev = pci_get_base_class(PCI_BASE_CLASS_DISPLAY, pdev)))
47
+
r = pci_find_resource(pdev, res);
48
+
49
+
if (!r || !pdev)
50
+
return NULL; /* not found; not an error */
51
+
52
+
if (!framebuffer_pci_dev_is_enabled(pdev)) {
53
+
pci_dev_put(pdev);
54
+
return ERR_PTR(-ENODEV);
55
+
}
56
+
57
+
return pdev;
58
+
}
59
+
#else
60
+
static struct pci_dev *framebuffer_parent_pci_dev(struct resource *res)
61
+
{
62
+
return NULL;
63
+
}
64
+
#endif
65
+
66
+
static struct device *framebuffer_parent_dev(struct resource *res)
67
+
{
68
+
struct pci_dev *pdev;
69
+
70
+
pdev = framebuffer_parent_pci_dev(res);
71
+
if (IS_ERR(pdev))
72
+
return ERR_CAST(pdev);
73
+
else if (pdev)
74
+
return &pdev->dev;
75
+
76
+
return NULL;
77
+
}
78
+
25
79
static const struct simplefb_format formats[] = SIMPLEFB_FORMATS;
26
80
27
81
static int framebuffer_probe(struct coreboot_device *dev)
28
82
{
29
83
int i;
30
84
struct lb_framebuffer *fb = &dev->framebuffer;
85
+
struct device *parent;
31
86
struct platform_device *pdev;
32
87
struct resource res;
88
+
int ret;
33
89
struct simplefb_platform_data pdata = {
34
90
.width = fb->x_resolution,
35
91
.height = fb->y_resolution,
···
115
57
if (res.end <= res.start)
116
58
return -EINVAL;
117
59
60
+
parent = framebuffer_parent_dev(&res);
61
+
if (IS_ERR(parent))
62
+
return PTR_ERR(parent);
63
+
118
64
for (i = 0; i < ARRAY_SIZE(formats); ++i) {
119
65
if (fb->bits_per_pixel == formats[i].bits_per_pixel &&
120
66
fb->red_mask_pos == formats[i].red.offset &&
···
129
67
fb->blue_mask_size == formats[i].blue.length)
130
68
pdata.format = formats[i].name;
131
69
}
132
-
if (!pdata.format)
133
-
return -ENODEV;
70
+
if (!pdata.format) {
71
+
ret = -ENODEV;
72
+
goto out_put_device_parent;
73
+
}
134
74
135
-
pdev = platform_device_register_resndata(&dev->dev,
75
+
pdev = platform_device_register_resndata(parent,
136
76
"simple-framebuffer", 0,
137
77
&res, 1, &pdata,
138
78
sizeof(pdata));
139
-
if (IS_ERR(pdev))
79
+
if (IS_ERR(pdev)) {
80
+
ret = PTR_ERR(pdev);
140
81
pr_warn("coreboot: could not register framebuffer\n");
82
+
goto out_put_device_parent;
83
+
}
141
84
142
-
return PTR_ERR_OR_ZERO(pdev);
85
+
ret = 0;
86
+
87
+
out_put_device_parent:
88
+
if (parent)
89
+
put_device(parent);
90
+
return ret;
143
91
}
144
92
145
93
static const struct coreboot_device_id framebuffer_ids[] = {