HSP_SM_SHRD_MBOX
tegra_hsp_channel_writel(channel, value, HSP_SM_SHRD_MBOX);
value = tegra_hsp_channel_readl(channel, HSP_SM_SHRD_MBOX);
tegra_hsp_channel_writel(channel, 0x0, HSP_SM_SHRD_MBOX);
value = tegra_hsp_channel_readl(ch, HSP_SM_SHRD_MBOX);