linux-kernel - Re: [PATCH v3 4/5] i3c: mipi-i3c-hci: use parity8 helper instead of open coding it

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] [day] [month] [year] [list]

Message-ID: <20250106130653.7fe81eae@pumpkin>
Date: Mon, 6 Jan 2025 13:06:53 +0000
From: David Laight <david.laight.linux@...il.com>
To: Wolfram Sang <wsa+renesas@...g-engineering.com>
Cc: linux-i3c@...ts.infradead.org, linux-kernel@...r.kernel.org,
 linux-renesas-soc@...r.kernel.org, Jarkko Nikula
 <jarkko.nikula@...ux.intel.com>, Alexandre Belloni
 <alexandre.belloni@...tlin.com>
Subject: Re: [PATCH v3 4/5] i3c: mipi-i3c-hci: use parity8 helper instead of
 open coding it

On Mon,  6 Jan 2025 10:27:22 +0100
Wolfram Sang <wsa+renesas@...g-engineering.com> wrote:

> The kernel has now a generic helper for getting parity with easier to
> understand semantics. Make use of it.

This need to explain that although the algorithm has changed the existing
code is wrong.

	David
 
> 
> Signed-off-by: Wolfram Sang <wsa+renesas@...g-engineering.com>
> Tested-by: Jarkko Nikula <jarkko.nikula@...ux.intel.com>
> ---
>  drivers/i3c/master/mipi-i3c-hci/dat_v1.c | 11 +----------
>  1 file changed, 1 insertion(+), 10 deletions(-)
> 
> diff --git a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
> index 47b9b4d4ed3f..85c4916972e4 100644
> --- a/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
> +++ b/drivers/i3c/master/mipi-i3c-hci/dat_v1.c
> @@ -40,15 +40,6 @@
>  #define dat_w0_write(i, v)	writel(v, hci->DAT_regs + (i) * 8)
>  #define dat_w1_write(i, v)	writel(v, hci->DAT_regs + (i) * 8 + 4)
>  
> -static inline bool dynaddr_parity(unsigned int addr)
> -{
> -	addr |= 1 << 7;
> -	addr += addr >> 4;
> -	addr += addr >> 2;
> -	addr += addr >> 1;
> -	return (addr & 1);
> -}
> -
>  static int hci_dat_v1_init(struct i3c_hci *hci)
>  {
>  	unsigned int dat_idx;
> @@ -123,7 +114,7 @@ static void hci_dat_v1_set_dynamic_addr(struct i3c_hci *hci,
>  	dat_w0 = dat_w0_read(dat_idx);
>  	dat_w0 &= ~(DAT_0_DYNAMIC_ADDRESS | DAT_0_DYNADDR_PARITY);
>  	dat_w0 |= FIELD_PREP(DAT_0_DYNAMIC_ADDRESS, address) |
> -		  (dynaddr_parity(address) ? DAT_0_DYNADDR_PARITY : 0);
> +		  (parity8(address) ? 0 : DAT_0_DYNADDR_PARITY);
>  	dat_w0_write(dat_idx, dat_w0);
>  }
>