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pci: Clear the MEM/PORT_EN bit when updating PCI BAR

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It's unsafe to update the BAR when the related EN bit is set.

Submitted by:	Dexuan Cui <decui microsoft com>
Reviewed by:	jhb
MFC after:	1 week
Sponsored by:	Microsoft
Differential Revision:	https://reviews.freebsd.org/D7914
This commit is contained in:
Sepherosa Ziehau 2016-09-27 06:00:10 +00:00
parent 1e6afa0eaf
commit 4d6e19e457
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=306359
1 changed files with 10 additions and 0 deletions
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10
sys/dev/pci/pci.c
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@ -5000,6 +5000,7 @@ pci_reserve_map(device_t dev, device_t child, int type, int *rid,
struct resource_list *rl = &dinfo->resources;
struct resource *res;
struct pci_map *pm;
uint16_t cmd;
pci_addr_t map, testval;
int mapsize;
@ -5089,8 +5090,17 @@ pci_reserve_map(device_t dev, device_t child, int type, int *rid,
device_printf(child,
"Lazy allocation of %#jx bytes rid %#x type %d at %#jx\n",
count, *rid, type, rman_get_start(res));
/* Disable decoding via the CMD register before updating the BAR */
cmd = pci_read_config(child, PCIR_COMMAND, 2);
pci_write_config(child, PCIR_COMMAND,
cmd & ~(PCI_BAR_MEM(map) ? PCIM_CMD_MEMEN : PCIM_CMD_PORTEN), 2);
map = rman_get_start(res);
pci_write_bar(child, pm, map);
/* Restore the original value of the CMD register */
pci_write_config(child, PCIR_COMMAND, cmd, 2);
out:
return (res);
}