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authorMaheswara Kurapati <quic_mkurapat@quicinc.com>2022-06-30 09:21:13 +0200
committerCédric Le Goater <clg@kaod.org>2022-06-30 09:21:13 +0200
commitdd0b3271e55d4017fd6cd6b4feb4da6ea6c5d1d7 (patch)
treec7b00b1c4b5f387397dfdba036e20ca485f12858 /hw/i2c
parentece4cccd67749e9b0955159b89b48f645a6c5847 (diff)
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hw/i2c: pmbus: Page #255 is valid page for read requests.
Current implementation of the pmbus core driver treats the read request for page 255 as invalid request and sets the invalid command bit (bit 7) in the STATUS_CML register. As per the PMBus specification it is a valid request. Refer to the PMBus specification, revision 1.3.1, section 11.10 PAGE, on the page 58: "Setting the PAGE to FFh means that all subsequent comands are to be applied to all outputs. Some commands, such as READ_TEMPERATURE, may use a common sensor but be available on all pages of a device. Such implementations are the decision of each device manufacturer or are specified in a PMBus Application Profile. Consult the manufacturer's documents or the Application Profile Specification as needed." For e.g., The VOUT_MODE is a valid command for page 255 for maxim 31785 device. refer to Table 1. PMBus Command Codes on page 14 in the datasheet. https://datasheets.maximintegrated.com/en/ds/MAX31785.pdf Fixes: 38870253f1d1 ("hw/i2c: pmbus: fix error returns and guard against out of range accesses") Signed-off-by: Maheswara Kurapati <quic_mkurapat@quicinc.com> Signed-off-by: Jae Hyun Yoo <quic_jaehyoo@quicinc.com> Reviewed-by: Titus Rwantare <titusr@google.com> Reviewed-by: Cédric Le Goater <clg@kaod.org> Message-Id: <20220627154703.148943-4-quic_jaehyoo@quicinc.com> Signed-off-by: Cédric Le Goater <clg@kaod.org>
Diffstat (limited to 'hw/i2c')
-rw-r--r--hw/i2c/pmbus_device.c6
1 files changed, 1 insertions, 5 deletions
diff --git a/hw/i2c/pmbus_device.c b/hw/i2c/pmbus_device.c
index 62885fa..749a33a 100644
--- a/hw/i2c/pmbus_device.c
+++ b/hw/i2c/pmbus_device.c
@@ -284,14 +284,10 @@ static uint8_t pmbus_receive_byte(SMBusDevice *smd)
/*
* Reading from all pages will return the value from page 0,
- * this is unspecified behaviour in general.
+ * means that all subsequent commands are to be applied to all output.
*/
if (pmdev->page == PB_ALL_PAGES) {
index = 0;
- qemu_log_mask(LOG_GUEST_ERROR,
- "%s: tried to read from all pages\n",
- __func__);
- pmbus_cml_error(pmdev);
} else if (pmdev->page > pmdev->num_pages - 1) {
qemu_log_mask(LOG_GUEST_ERROR,
"%s: page %d is out of range\n",