linux-kernel - Re: [PATCH RESEND v3 2/6] i3c: mipi-i3c-hci: Read HC_CONTROL_PIO

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <62efb2bc-152e-4970-88b9-4d40865bc457@amd.com>
Date: Fri, 9 Aug 2024 21:16:05 +0530
From: Shyam Sundar S K <Shyam-sundar.S-k@....com>
To: Jarkko Nikula <jarkko.nikula@...ux.intel.com>,
 Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc: Guruvendra Punugupati <Guruvendra.Punugupati@....com>,
 Krishnamoorthi M <krishnamoorthi.m@....com>, linux-i3c@...ts.infradead.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH RESEND v3 2/6] i3c: mipi-i3c-hci: Read HC_CONTROL_PIO_MODE
 only after i3c hci v1.1



On 8/9/2024 18:51, Jarkko Nikula wrote:
> Hi
> 
> On 8/7/24 8:23 AM, Shyam Sundar S K wrote:
>> The HC_CONTROL_PIO_MODE bit was introduced in the HC_CONTROL register
>> starting from version 1.1. Therefore, checking the
>> HC_CONTROL_PIO_MODE bit
>> on hardware that adheres to older specification revisions (i.e.,
>> versions
>> earlier than 1.1) is incorrect. To address this, add an additional
>> check
>> to read the HCI version before attempting to read the
>> HC_CONTROL_PIO_MODE
>> status.
>>
>> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@....com>
>> ---
>>   drivers/i3c/master/mipi-i3c-hci/core.c | 5 +++--
>>   1 file changed, 3 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/i3c/master/mipi-i3c-hci/core.c
>> b/drivers/i3c/master/mipi-i3c-hci/core.c
>> index 24dd4603d6c6..a16da70bdfe1 100644
>> --- a/drivers/i3c/master/mipi-i3c-hci/core.c
>> +++ b/drivers/i3c/master/mipi-i3c-hci/core.c
>> @@ -33,6 +33,7 @@
>>   #define reg_clear(r, v)        reg_write(r, reg_read(r) & ~(v))
>>     #define HCI_VERSION            0x00    /* HCI Version (in BCD) */
>> +#define HCI_VERSION_V1            0x100   /* MIPI HCI Version
>> number V1.0 */
>>     #define HC_CONTROL            0x04
>>   #define HC_CONTROL_BUS_ENABLE        BIT(31)
>> @@ -756,7 +757,7 @@ static int i3c_hci_init(struct i3c_hci *hci)
>>       /* Try activating DMA operations first */
>>       if (hci->RHS_regs) {
>>           reg_clear(HC_CONTROL, HC_CONTROL_PIO_MODE);
>> -        if (reg_read(HC_CONTROL) & HC_CONTROL_PIO_MODE) {
>> +        if (regval > HCI_VERSION_V1 && !(reg_read(HC_CONTROL) &
>> HC_CONTROL_PIO_MODE)) {
>>               dev_err(&hci->master.dev, "PIO mode is stuck\n");
>>               ret = -EIO;
>>           } else {
> 
> Here's typo and logic is reversed.

ah! good catch! thanks, will change this in the next version.

Thanks,
Shyam