From dd0b3271e55d4017fd6cd6b4feb4da6ea6c5d1d7 Mon Sep 17 00:00:00 2001 From: Maheswara Kurapati Date: Thu, 30 Jun 2022 09:21:13 +0200 Subject: [PATCH] hw/i2c: pmbus: Page #255 is valid page for read requests. MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 Signed-off-by: Jae Hyun Yoo Reviewed-by: Titus Rwantare Reviewed-by: Cédric Le Goater Message-Id: <20220627154703.148943-4-quic_jaehyoo@quicinc.com> Signed-off-by: Cédric Le Goater --- hw/i2c/pmbus_device.c | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) diff --git a/hw/i2c/pmbus_device.c b/hw/i2c/pmbus_device.c index 62885fa6a1..749a33af82 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",