Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
drm/ast: Rework I/O register setup
There are three different ways of retrieving the I/O-memory ranges
for AST devices: either from PCI BAR 1, from PCI BAR 2 or from PCI
BAR 1 by 'guessing'.
Make the respective code more readable by making each case self-
contained. Also add error checking against the length of the PCI
BARs.
v2:
* fix I/O range length to 128 bytes
* fix length test for PCI BAR 2
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20231116100240.22975-3-tzimmermann@suse.de
+32
-11
+31
-11
drivers/gpu/drm/ast/ast_main.c
+31
-11
drivers/gpu/drm/ast/ast_main.c
···
444
444
if (!ast->regs)
445
445
return ERR_PTR(-EIO);
446
446
447
-
/*
448
-
* After AST2500, MMIO is enabled by default, and it should be adopted
449
-
* to be compatible with Arm.
450
-
*/
451
447
if (pdev->revision >= 0x40) {
452
-
ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
453
-
} else if (!(pci_resource_flags(pdev, 2) & IORESOURCE_IO)) {
454
-
drm_info(dev, "platform has no IO space, trying MMIO\n");
455
-
ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
456
-
}
448
+
/*
449
+
* On AST2500 and later models, MMIO is enabled by
450
+
* default. Adopt it to be compatible with ARM.
451
+
*/
452
+
resource_size_t len = pci_resource_len(pdev, 1);
457
453
458
-
/* "map" IO regs if the above hasn't done so already */
459
-
if (!ast->ioregs) {
454
+
if (len < AST_IO_MM_OFFSET)
455
+
return ERR_PTR(-EIO);
456
+
if ((len - AST_IO_MM_OFFSET) < AST_IO_MM_LENGTH)
457
+
return ERR_PTR(-EIO);
458
+
ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
459
+
} else if (pci_resource_flags(pdev, 2) & IORESOURCE_IO) {
460
+
/*
461
+
* Map I/O registers if we have a PCI BAR for I/O.
462
+
*/
463
+
resource_size_t len = pci_resource_len(pdev, 2);
464
+
465
+
if (len < AST_IO_MM_LENGTH)
466
+
return -EIO;
460
467
ast->ioregs = pcim_iomap(pdev, 2, 0);
461
468
if (!ast->ioregs)
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469
return ERR_PTR(-EIO);
470
+
} else {
471
+
/*
472
+
* Anything else is best effort.
473
+
*/
474
+
resource_size_t len = pci_resource_len(pdev, 1);
475
+
476
+
if (len < AST_IO_MM_OFFSET)
477
+
return ERR_PTR(-EIO);
478
+
if ((len - AST_IO_MM_OFFSET) < AST_IO_MM_LENGTH)
479
+
return ERR_PTR(-EIO);
480
+
ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
481
+
482
+
drm_info(dev, "Platform has no I/O space, using MMIO\n");
463
483
}
464
484
465
485
if (!ast_is_vga_enabled(dev)) {