On Thu, May 4, 2017 at 12:28 PM, Moore, Robert <robert.moore@xxxxxxxxx> wrote: > Jon, > > You might want to take a look at using the acpi_read and acpi_write ACPICA interfaces that accept a GAS structure and handle the access width (etc.) automatically. > > Bob This function in SPCR is using common code for the early console. So the acpi_read/write would not be usable in that common code. Thanks, Jon > > >> -----Original Message----- >> From: Jon Mason [mailto:jon.mason@xxxxxxxxxxxx] >> Sent: Thursday, May 4, 2017 8:06 AM >> To: Rafael Wysocki <rjw@xxxxxxxxxxxxx>; Len Brown <lenb@xxxxxxxxxx>; >> Moore, Robert <robert.moore@xxxxxxxxx>; Zheng, Lv <lv.zheng@xxxxxxxxx> >> Cc: linux-acpi@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; >> devel@xxxxxxxxxx; bcm-kernel-feedback-list@xxxxxxxxxxxx >> Subject: [PATCH] ACPI: SPCR: Use access width to determine mmio usage >> >> The current SPCR code does not check the access width of the mmio, and >> uses a default of 8bit register accesses. This prevents devices that >> only do 16 or 32bit register accesses from working. By simply checking >> this field and setting the mmio string appropriately, this issue can be >> corrected. To prevent any legacy issues, the code will default to 8bit >> accesses if the value is anything but 16 or 32. >> >> Signed-off-by: Jon Mason <jon.mason@xxxxxxxxxxxx> >> --- >> drivers/acpi/spcr.c | 18 ++++++++++++++++-- >> include/acpi/acrestyp.h | 7 +++++++ >> 2 files changed, 23 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/acpi/spcr.c b/drivers/acpi/spcr.c index >> 01c9466..11233f6 100644 >> --- a/drivers/acpi/spcr.c >> +++ b/drivers/acpi/spcr.c >> @@ -74,8 +74,22 @@ int __init parse_spcr(bool earlycon) >> goto done; >> } >> >> - iotype = table->serial_port.space_id == >> ACPI_ADR_SPACE_SYSTEM_MEMORY ? >> - "mmio" : "io"; >> + if (table->serial_port.space_id == ACPI_ADR_SPACE_SYSTEM_MEMORY) { >> + switch (table->serial_port.access_width) { >> + default: >> + pr_err("Unexpected SPCR Access Width. Defaulting to >> byte size\n"); >> + case ACPI_ACCESS_SIZE_BYTE: >> + iotype = "mmio"; >> + break; >> + case ACPI_ACCESS_SIZE_WORD: >> + iotype = "mmio16"; >> + break; >> + case ACPI_ACCESS_SIZE_DWORD: >> + iotype = "mmio32"; >> + break; >> + } >> + } else >> + iotype = "io"; >> >> switch (table->interface_type) { >> case ACPI_DBG2_ARM_SBSA_32BIT: >> diff --git a/include/acpi/acrestyp.h b/include/acpi/acrestyp.h index >> f0f7403..781cb55 100644 >> --- a/include/acpi/acrestyp.h >> +++ b/include/acpi/acrestyp.h >> @@ -372,6 +372,13 @@ struct acpi_resource_generic_register { >> u64 address; >> }; >> >> +/* Generic Address Space Access Sizes */ >> +#define ACPI_ACCESS_SIZE_UNDEFINED 0 >> +#define ACPI_ACCESS_SIZE_BYTE 1 >> +#define ACPI_ACCESS_SIZE_WORD 2 >> +#define ACPI_ACCESS_SIZE_DWORD 3 >> +#define ACPI_ACCESS_SIZE_QWORD 4 >> + >> struct acpi_resource_gpio { >> u8 revision_id; >> u8 connection_type; >> -- >> 2.7.4 > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
