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drm/ast: Rework I/O register setup

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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
This commit is contained in:
Thomas Zimmermann
2023-11-16 10:59:21 +01:00
parent c350a08ac7
commit 0ccaa3dde9
2 changed files with 32 additions and 11 deletions
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42
drivers/gpu/drm/ast/ast_main.c
View File

@@ -444,22 +444,42 @@ struct ast_device *ast_device_create(const struct drm_driver *drv,
if (!ast->regs)
return ERR_PTR(-EIO);
/*
* After AST2500, MMIO is enabled by default, and it should be adopted
* to be compatible with Arm.
*/
if (pdev->revision >= 0x40) {
ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
} else if (!(pci_resource_flags(pdev, 2) & IORESOURCE_IO)) {
drm_info(dev, "platform has no IO space, trying MMIO\n");
ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
}
/*
* On AST2500 and later models, MMIO is enabled by
* default. Adopt it to be compatible with ARM.
*/
resource_size_t len = pci_resource_len(pdev, 1);
/* "map" IO regs if the above hasn't done so already */
if (!ast->ioregs) {
if (len < AST_IO_MM_OFFSET)
return ERR_PTR(-EIO);
if ((len - AST_IO_MM_OFFSET) < AST_IO_MM_LENGTH)
return ERR_PTR(-EIO);
ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
} else if (pci_resource_flags(pdev, 2) & IORESOURCE_IO) {
/*
* Map I/O registers if we have a PCI BAR for I/O.
*/
resource_size_t len = pci_resource_len(pdev, 2);
if (len < AST_IO_MM_LENGTH)
return -EIO;
ast->ioregs = pcim_iomap(pdev, 2, 0);
if (!ast->ioregs)
return ERR_PTR(-EIO);
} else {
/*
* Anything else is best effort.
*/
resource_size_t len = pci_resource_len(pdev, 1);
if (len < AST_IO_MM_OFFSET)
return ERR_PTR(-EIO);
if ((len - AST_IO_MM_OFFSET) < AST_IO_MM_LENGTH)
return ERR_PTR(-EIO);
ast->ioregs = ast->regs + AST_IO_MM_OFFSET;
drm_info(dev, "Platform has no I/O space, using MMIO\n");
}
if (!ast_is_vga_enabled(dev)) {

1
drivers/gpu/drm/ast/ast_reg.h
View File

@@ -10,6 +10,7 @@
*/
#define AST_IO_MM_OFFSET (0x380)
#define AST_IO_MM_LENGTH (128)
#define AST_IO_VGAARI_W (0x40)
#define AST_IO_VGAMR_W (0x42)