[U-Boot] [PATCH 0/4] Update SiFive Unleashed Clock Driver

[Troy Benjegerdes]

> On Jun 18, 2019, at 4:18 AM, Anup Patel <Anup.Patel at wdc.com> wrote:
> 
> This series update SiFive Unleashed clock driver so that:
> 1. It is in sync with upstream Linux driver
> 2. It uses latest DT bindings as-per upstream Linux driver
> 
> With this series, we can now use latest DT bindings with U-Boot. I have
> tested SiFive Serial driver and Cadence MACB ethernet driver with this
> changes and both work fine.
> 
> The legacy FSBL will still pass DTB to U-Boot with older DT bindings
> which will break the updated SiFive Unleashed clock driver. To tackle
> this, we have embedded DTB in OpenSBI FW_PAYLOAD firmware for SiFive
> Unleashed so that OpenSBI will override and pass updated DTB to U-Boot.
> 
> In fact, the updated DTB passed by OpenSBI can be used by latest Linux
> (i.e. V5.2-rc1 or higher) as well.
> 
> The OpenSBI changes to embed SiFive Unleashed DTB can be found in
> sifive_unleashed_dtb_fix_v1 branch of:
> https://github.com/avpatel/opensbi.git
> 
> This series can be found in riscv_unleashed_clk_sync_v1 branch of:
> https://github.com/avpatel/u-boot.git

There are some discrepancies I’m finding in the clocking… If I use the
HiFive_U-Boot as FSBL, it does the following (with some extra debug
code)

U-Boot 2018.09-g8bbdd51-dirty (Jun 18 2019 - 19:46:55 -0700)

DRAM:  2 GiB
MMC:
In:    serial
Out:   serial
Err:   serial
Net:   gem_mdc_clk_div: macb_hz: 500000000
gmac0
Hit any key to stop autoboot:  0

Where as the close-to-u-boot master version does this:

U-Boot 2019.07-rc4-05661-gc998035-dirty (Jun 18 2019 - 19:51:10 -0700)

CPU:   rv64imafdc
Model: sifive,hifive-unleashed-a00
DRAM:  8 GiB
In:    serial at 10010000
Out:   serial at 10010000
Err:   serial at 10010000
Net:   gem_mdc_clk_div: macb_hz: 933333324

For reference, I’ve checked all my changes into the ‘dev/new-dts’ branch
of github.com/tmagik/freedom-u-sdk, and the ‘make test_s’ target will build
and then copy various files to /var/lib/tftpboot to run the test, and assumes
you have a DHCP and TFTP server running locally.

Another issue with the mainline u-boot is it does not have the OTP driver
that the HiFive_U-Boot version does, so when it selects a random mac
address this causes TFTP to fail in one of my test environments.

FYI, the patch applied is:

diff --git a/drivers/net/macb.c b/drivers/net/macb.c
index 5a6cba5..d21026d 100644
--- a/drivers/net/macb.c
+++ b/drivers/net/macb.c
@@ -813,6 +813,8 @@ static u32 macb_mdc_clk_div(int id, struct macb_device *macb)
        unsigned long macb_hz = HIFIVE_ETHERNET_CLK_FREQ;//get_macb_pclk_rate(id);
 #endif
 
+       printf("%s: macb_hz: %d\n", __func__, macb_hz);
+
        if (macb_hz < 20000000)
                config = MACB_BF(CLK, MACB_CLK_DIV8);
        else if (macb_hz < 40000000)
@@ -835,6 +837,7 @@ static u32 gem_mdc_clk_div(int id, struct macb_device *macb)
        unsigned long macb_hz = HIFIVE_ETHERNET_CLK_FREQ;//get_macb_pclk_rate(id);
 #endif
 
+       printf("%s: macb_hz: %d\n", __func__, macb_hz);
        if (macb_hz < 20000000)
                config = GEM_BF(CLK, GEM_CLK_DIV8);
        else if (macb_hz < 40000000)