Hello.
On 7/7/2015 2:41 AM, Andy Falanga (afalanga) wrote:
I'm working with the registers in an AHCI controller. The memory
address contained in PxCLB and PxCLBU (if 64-bit addressing is
supported): what kind of address are they?
Apparently, physical. The hardware only operates on the physical addresses.
Currently, when I get the
address and place it into a pointer of struct ahci_cmd_hdr and try to
dereference, my VM locks and then reboots. What am I doing incorrectly?
You can't de-reference physical addresses.
Basically, I have this:
void __iomem * pbase = ahci_port_base((struct ata_port*));
Can't parse this.
struct ahci_cmd_hdr *cmd_hdr = NULL;
cmd_hdr = (struct ahci_cmd_hdr*)(u64)
((u64)(*(temp + PORT_LST_ADDR_HI)) << 32 | *temp);
temp?
pr_info("cmd_hdr is %p\n", cmd_hdr);
pr_info("cmd_hdr->opts is %d\n", cmd_hdr->opts); /* opts is __le32 */
At the last line above my VM hangs and reboots. The memory address is
something like 0x0000000037900000. This address makes me think that I
simply can't dereference it but I'm quite new to this and I don't know
what I should do. I'd appreciate any help even if that's a pointer (no
pun intended) to a more appropriate forum.
The corresponding virtual address seems to be contained in
ahci_port_priv::cmd_slot.
Thanks,
Andy
WBR, Sergei
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