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| author | Joel Stanley <joel@jms.id.au> | 2020-07-28 04:55:25 +0200 |
|---|---|---|
| committer | Joel Stanley <joel@jms.id.au> | 2020-09-10 04:53:17 +0200 |
| commit | 4a80c2017bd9136a139773ba980341ea7e71dafd (patch) | |
| tree | 56156826ed8a52ba2697b6deb7bcf0bf2ffcfd4d | |
| parent | fsi: aspeed: Support cabled FSI (diff) | |
| download | linux-4a80c2017bd9136a139773ba980341ea7e71dafd.tar.xz linux-4a80c2017bd9136a139773ba980341ea7e71dafd.zip | |
fsi: aspeed: Run the bus at maximum speed
Testing of Tacoma has shown that the ASPEED master can be run at maximum
speed.
The exception is when wired externally with a cable, in which case we
use a divisor of two to ensure reliable operation.
Reviewed-by: Eddie James <eajames@linux.ibm.com>
Link: https://lore.kernel.org/r/20200728025527.174503-4-joel@jms.id.au
Signed-off-by: Joel Stanley <joel@jms.id.au>
| -rw-r--r-- | drivers/fsi/fsi-master-aspeed.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/drivers/fsi/fsi-master-aspeed.c b/drivers/fsi/fsi-master-aspeed.c index c282de76e6e7..f503f64ab32b 100644 --- a/drivers/fsi/fsi-master-aspeed.c +++ b/drivers/fsi/fsi-master-aspeed.c @@ -83,7 +83,11 @@ static const u32 fsi_base = 0xa0000000; #define FSI_LINK_ENABLE_SETUP_TIME 10 /* in mS */ -#define DEFAULT_DIVISOR 14 +/* Run the bus at maximum speed by default */ +#define FSI_DIVISOR_DEFAULT 1 +#define FSI_DIVISOR_CABLED 2 +static u16 aspeed_fsi_divisor = FSI_DIVISOR_DEFAULT; + #define OPB_POLL_TIMEOUT 10000 static int __opb_write(struct fsi_master_aspeed *aspeed, u32 addr, @@ -385,9 +389,11 @@ static int aspeed_master_init(struct fsi_master_aspeed *aspeed) opb_writel(aspeed, ctrl_base + FSI_MECTRL, reg); reg = cpu_to_be32(FSI_MMODE_ECRC | FSI_MMODE_EPC | FSI_MMODE_RELA - | fsi_mmode_crs0(DEFAULT_DIVISOR) - | fsi_mmode_crs1(DEFAULT_DIVISOR) + | fsi_mmode_crs0(aspeed_fsi_divisor) + | fsi_mmode_crs1(aspeed_fsi_divisor) | FSI_MMODE_P8_TO_LSB); + dev_info(aspeed->dev, "mmode set to %08x (divisor %d)\n", + be32_to_cpu(reg), aspeed_fsi_divisor); opb_writel(aspeed, ctrl_base + FSI_MMODE, reg); reg = cpu_to_be32(0xffff0000); @@ -446,6 +452,11 @@ static int tacoma_cabled_fsi_fixup(struct device *dev) /* If the routing GPIO is high we should set the mux to low. */ if (gpio) { + /* + * Cable signal integrity means we should run the bus + * slightly slower + */ + aspeed_fsi_divisor = FSI_DIVISOR_CABLED; gpiod_direction_output(mux_gpio, 0); dev_info(dev, "FSI configured for external cable\n"); } else { |