Hi Jingoo, On 2015/8/25 19:14, Jingoo Han wrote: > On 2015. 8. 25., at PM 7:35, Zhou Wang <wangzhou1@xxxxxxxxxxxxx> wrote: >> >> The value under PORT_LOGIC_LINK_WIDTH_MASK is 0x1, 0x2, 0x4, 0x8. Here change >> this mask to proper value. >> >> In fact, for DesignWare PCIe IP version 4.4, it only uses bit8~12 to indicate >> number of lanes. Original mask will bring a mistake. > > NAK Sorry, maybe above commit message is no very clear. Will explain it below. > > The definitions of bits of registers should be defined based on hardware manual such as datasheet, databook. > > According to the databook, the bits [16:8] are defined for NUM_OF_LANES. Yes, according to databook of v4.2, bits [16:8] are defined for NUM_OF_LANES. > > In the future, if 16 lanes or 32 lanes is supported and 12th bit or 13th bit is used, what will you do? > > Then, in the version 4.4 IP, the bits[16:13] are used for other usage? > Yes, according to databook of v4.4, bits [12:8] are defined for NUM_OF_LANES. [16:13] are for other usages(bit16 is AUTO_LANE_FLIP_CTRL_EN, bits [15:13] are PRE_DET_LANE). For details, maybe you can refer to v4.4 databook :) My opinion is that there is no conflict about NUM_OF_LANES between v4.2 and v4.4. We can change this mask to avoid future problem. Thanks Zhou > Best regards, > Jingoo Han > >> Signed-off-by: Zhou Wang <wangzhou1@xxxxxxxxxxxxx> >> --- >> drivers/pci/host/pcie-designware.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/pci/host/pcie-designware.c b/drivers/pci/host/pcie-designware.c >> index 69486be..eb549b9 100644 >> --- a/drivers/pci/host/pcie-designware.c >> +++ b/drivers/pci/host/pcie-designware.c >> @@ -35,7 +35,7 @@ >> >> #define PCIE_LINK_WIDTH_SPEED_CONTROL 0x80C >> #define PORT_LOGIC_SPEED_CHANGE (0x1 << 17) >> -#define PORT_LOGIC_LINK_WIDTH_MASK (0x1ff << 8) >> +#define PORT_LOGIC_LINK_WIDTH_MASK (0x1f << 8) >> #define PORT_LOGIC_LINK_WIDTH_1_LANES (0x1 << 8) >> #define PORT_LOGIC_LINK_WIDTH_2_LANES (0x2 << 8) >> #define PORT_LOGIC_LINK_WIDTH_4_LANES (0x4 << 8) >> -- >> 1.9.1 >> > > . > -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
