linux-kernel - [PATCH v2 11/11] fsi: aspeed: Fix OPB0 byte order register values

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]

Date:   Fri,  8 Nov 2019 15:49:45 +1030
From:   Joel Stanley <joel@....id.au>
To:     Rob Herring <robh+dt@...nel.org>,
        Greg KH <gregkh@...uxfoundation.org>,
        Jeremy Kerr <jk@...abs.org>
Cc:     Andrew Jeffery <andrew@...id.au>,
        Alistar Popple <alistair@...ple.id.au>,
        Eddie James <eajames@...ux.ibm.com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ingo Molnar <mingo@...hat.com>, linux-kernel@...r.kernel.org,
        devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-fsi@...ts.ozlabs.org
Subject: [PATCH v2 11/11] fsi: aspeed: Fix OPB0 byte order register values

From: Andrew Jeffery <andrew@...id.au>

The data byte order selection registers in the APB2OPB primarily expose some
internal plumbing necessary to get correct write accesses onto the OPB.
OPB write cycles require "data mirroring" across the 32-bit data bus to
support variable data width slaves that don't implement "byte enables".
For slaves that do implement byte enables the master can signal which
bytes on the data bus the slave should consider valid.

The data mirroring behaviour is specified by the following table:

    +-----------------+----------+-----------------------------------+
    |                 |          |          32-bit Data Bus          |
    +---------+-------+----------+---------+---------+-------+-------+
    |         |       |          |         |         |       |       |
    |   ABus  | Mn_BE |  Request |   Dbus  |   Dbus  |  Dbus |  Dbus |
    | (30:31) | (0:3) | Transfer |   0:7   |   8:15  | 16:23 | 24:31 |
    |         |       |   Size   |  byte0  |  byte1  | byte2 | byte3 |
    +---------+-------+----------+---------+---------+-------+-------+
    |    00   |  1111 | fullword |  byte0  |  byte1  | byte2 | byte3 |
    +---------+-------+----------+---------+---------+-------+-------+
    |    00   |  1110 | halfword |  byte0  |  byte1  | byte2 |       |
    +---------+-------+----------+---------+---------+-------+-------+
    |    01   |  0111 |   byte   | _byte1_ |  byte1  | byte2 | byte3 |
    +---------+-------+----------+---------+---------+-------+-------+
    |    00   |  1100 | halfword |  byte0  |  byte1  |       |       |
    +---------+-------+----------+---------+---------+-------+-------+
    |    01   |  0110 |   byte   | _byte1_ |  byte1  | byte2 |       |
    +---------+-------+----------+---------+---------+-------+-------+
    |    10   |  0011 | halfword | _byte2_ | _byte3_ | byte2 | byte3 |
    +---------+-------+----------+---------+---------+-------+-------+
    |    00   |  1000 |   byte   |  byte0  |         |       |       |
    +---------+-------+----------+---------+---------+-------+-------+
    |    01   |  0100 |   byte   | _byte1_ |  byte1  |       |       |
    +---------+-------+----------+---------+---------+-------+-------+
    |    10   |  0010 |   byte   | _byte2_ |         | byte2 |       |
    +---------+-------+----------+---------+---------+-------+-------+
    |    11   |  0001 |   byte   | _byte3_ | _byte3_ |       | byte3 |
    +---------+-------+----------+---------+---------+-------+-------+

Mirrored data values are highlighted by underscores in the Dbus columns.
The values in the ABus and Request Transfer Size columns correspond to
values in the field names listed in the write data order select register
descriptions.

Similar configuration registers are exposed for reads which enables the
secondary purpose of configuring hardware endian conversions. It appears the
data bus byte order is switched around in hardware so set the registers such
that we can access the correct values for all widths. The values were
determined by experimentation on hardware against fixed CFAM register
values to configure the read data order, then in combination with the
table above and the register layout documentation in the AST2600
datasheet performing write/read cycles to configure the write data order
registers.

Signed-off-by: Andrew Jeffery <andrew@...id.au>
Signed-off-by: Joel Stanley <joel@....id.au>
---
 drivers/fsi/fsi-master-aspeed.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/fsi/fsi-master-aspeed.c b/drivers/fsi/fsi-master-aspeed.c
index 95e226ac78b9..f49742b310c2 100644
--- a/drivers/fsi/fsi-master-aspeed.c
+++ b/drivers/fsi/fsi-master-aspeed.c
@@ -459,11 +459,11 @@ static int fsi_master_aspeed_probe(struct platform_device *pdev)
 	writel(fsi_base, aspeed->base + OPB_FSI_BASE);
 
 	/* Set read data order */
-	writel(0x0011bb1b, aspeed->base + OPB0_READ_ORDER1);
+	writel(0x00030b1b, aspeed->base + OPB0_READ_ORDER1);
 
 	/* Set write data order */
-	writel(0x0011bb1b, aspeed->base + OPB0_WRITE_ORDER1);
-	writel(0xffaa5500, aspeed->base + OPB0_WRITE_ORDER2);
+	writel(0x0011101b, aspeed->base + OPB0_WRITE_ORDER1);
+	writel(0x0c330f3f, aspeed->base + OPB0_WRITE_ORDER2);
 
 	/*
 	 * Select OPB0 for all operations.
-- 
2.24.0.rc1