| Message ID | 1388241295-20051-3-git-send-email-zhangfei.gao@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Saturday 28 December 2013, Zhangfei Gao wrote: > Add dw_mmc-k3.c for k3v2, support sd/emmc > > Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org> > Signed-off-by: Zhigang Wang <brooke.wangzhigang@huawei.com> > --- > .../devicetree/bindings/mmc/k3-dw-mshc.txt | 60 ++++++++++ > drivers/mmc/host/Kconfig | 10 ++ > drivers/mmc/host/Makefile | 1 + > drivers/mmc/host/dw_mmc-k3.c | 126 ++++++++++++++++++++ > 4 files changed, 197 insertions(+) > create mode 100644 Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt > create mode 100644 drivers/mmc/host/dw_mmc-k3.c > > diff --git a/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt > new file mode 100644 > index 000000000000..d7e2d7f159bb > --- /dev/null > +++ b/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt > @@ -0,0 +1,60 @@ > +* Hisilicon specific extensions to the Synopsys Designware Mobile > + Storage Host Controller > + > +Read synopsys-dw-mshc.txt for more details > + > +The Synopsys designware mobile storage host controller is used to interface > +a SoC with storage medium such as eMMC or SD/MMC cards. This file documents > +differences between the core Synopsys dw mshc controller properties described > +by synopsys-dw-mshc.txt and the properties used by the Hisilicon specific > +extensions to the Synopsys Designware Mobile Storage Host Controller. > + > +Required Properties: > + > +* compatible: should be one of the following. > + - "hisilicon,hi4511-dw-mshc": for controllers with hi4511 specific extentions. I wonder if this is actually a different variant of the mshc hardware, or just wired up in a different way. Do you know details? Since the only difference in the binding is the presence of the "clock-freq-table" property, we could also make this property generic for the mshc driver and use it if present but fall back to the normal behavior when it is absent. > +* clock-freq-table: should be the frequency (in Hz) array of the ciu clock > + in each supported mode. > + 0. CIU clock rate in Hz for DS mode > + 1. CIU clock rate in Hz for MMC HS mode > + 2. CIU clock rate in Hz for SD HS mode > + 3. CIU clock rate in Hz for SDR12 mode > + 4. CIU clock rate in Hz for SDR25 mode > + 5. CIU clock rate in Hz for SDR50 mode > + 6. CIU clock rate in Hz for SDR104 mode > + 7. CIU clock rate in Hz for DDR50 mode > + 8. CIU clock rate in Hz for HS200 mode This looks god now. > +static void dw_mci_k3_set_ios(struct dw_mci *host, struct mmc_ios *ios) > +{ > + struct dw_mci_k3_priv_data *priv = host->priv; > + u32 rate = priv->clk_table[ios->timing]; > + int ret; I think this should have some range checking to see if the mode that is being set had a clock frequency set in the DT. > + > + ret = clk_set_rate(host->ciu_clk, rate); > + if (ret) > + dev_warn(host->dev, "failed to set clock rate %uHz\n", rate); > + > + host->bus_hz = clk_get_rate(host->ciu_clk); > +} Why do you call clk_get_rate() here, shouldn't it always be the same rate that you have just set? > +static int dw_mci_k3_parse_dt(struct dw_mci *host) > +{ > + struct dw_mci_k3_priv_data *priv; > + struct device_node *node = host->dev->of_node; > + struct property *prop; > + const __be32 *cur; > + u32 val, num = 0; > + > + priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL); > + if (!priv) { > + dev_err(host->dev, "mem alloc failed for private data\n"); > + return -ENOMEM; > + } > + host->priv = priv; > + > + of_property_for_each_u32(node, "clock-freq-table", prop, cur, val) { > + if (num >= MAX_NUMS) > + break; > + priv->clk_table[num++] = val; > + } > + return 0; > +} If we make this property part of the generic binding, this function could also get moved to the main dw_mci driver. > +static int dw_mci_k3_suspend(struct device *dev) > +{ > + struct dw_mci *host = dev_get_drvdata(dev); > + int ret = 0; > + > + ret = dw_mci_suspend(host); You should never initialize local variables when they are set later in the function (the ret = 0 part above). For more complex functions, this prevents gcc from warning you about accidentally uninitialized uses. > + if (!ret) > + clk_disable_unprepare(host->ciu_clk); > + > + return ret; > +} The suspend/resume code also looks very generic. Can't we make these the default for dw-mci? If you do both, you won't even need a k3 specific driver. I think in general we should try hard to add code like this to the common driver when there is a chance that it can be shared with other platforms. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 12/30/2013 06:05 AM, Arnd Bergmann wrote: > On Saturday 28 December 2013, Zhangfei Gao wrote: >> Add dw_mmc-k3.c for k3v2, support sd/emmc >> >> Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org> >> Signed-off-by: Zhigang Wang <brooke.wangzhigang@huawei.com> >> --- >> .../devicetree/bindings/mmc/k3-dw-mshc.txt | 60 ++++++++++ >> drivers/mmc/host/Kconfig | 10 ++ >> drivers/mmc/host/Makefile | 1 + >> drivers/mmc/host/dw_mmc-k3.c | 126 ++++++++++++++++++++ >> 4 files changed, 197 insertions(+) >> create mode 100644 Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt >> create mode 100644 drivers/mmc/host/dw_mmc-k3.c >> >> diff --git a/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt >> new file mode 100644 >> index 000000000000..d7e2d7f159bb >> --- /dev/null >> +++ b/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt >> @@ -0,0 +1,60 @@ >> +* Hisilicon specific extensions to the Synopsys Designware Mobile >> + Storage Host Controller >> + >> +Read synopsys-dw-mshc.txt for more details >> + >> +The Synopsys designware mobile storage host controller is used to interface >> +a SoC with storage medium such as eMMC or SD/MMC cards. This file documents >> +differences between the core Synopsys dw mshc controller properties described >> +by synopsys-dw-mshc.txt and the properties used by the Hisilicon specific >> +extensions to the Synopsys Designware Mobile Storage Host Controller. >> + >> +Required Properties: >> + >> +* compatible: should be one of the following. >> + - "hisilicon,hi4511-dw-mshc": for controllers with hi4511 specific extentions. > > I wonder if this is actually a different variant of the mshc hardware, or just > wired up in a different way. Do you know details? > > Since the only difference in the binding is the presence of the "clock-freq-table" > property, we could also make this property generic for the mshc driver and use > it if present but fall back to the normal behavior when it is absent. > >> +* clock-freq-table: should be the frequency (in Hz) array of the ciu clock >> + in each supported mode. >> + 0. CIU clock rate in Hz for DS mode >> + 1. CIU clock rate in Hz for MMC HS mode >> + 2. CIU clock rate in Hz for SD HS mode >> + 3. CIU clock rate in Hz for SDR12 mode >> + 4. CIU clock rate in Hz for SDR25 mode >> + 5. CIU clock rate in Hz for SDR50 mode >> + 6. CIU clock rate in Hz for SDR104 mode >> + 7. CIU clock rate in Hz for DDR50 mode >> + 8. CIU clock rate in Hz for HS200 mode > > This looks god now. > >> +static void dw_mci_k3_set_ios(struct dw_mci *host, struct mmc_ios *ios) >> +{ >> + struct dw_mci_k3_priv_data *priv = host->priv; >> + u32 rate = priv->clk_table[ios->timing]; >> + int ret; > > I think this should have some range checking to see if the mode that is > being set had a clock frequency set in the DT. > >> + >> + ret = clk_set_rate(host->ciu_clk, rate); >> + if (ret) >> + dev_warn(host->dev, "failed to set clock rate %uHz\n", rate); >> + >> + host->bus_hz = clk_get_rate(host->ciu_clk); >> +} > > Why do you call clk_get_rate() here, shouldn't it always be the same > rate that you have just set? > >> +static int dw_mci_k3_parse_dt(struct dw_mci *host) >> +{ >> + struct dw_mci_k3_priv_data *priv; >> + struct device_node *node = host->dev->of_node; >> + struct property *prop; >> + const __be32 *cur; >> + u32 val, num = 0; >> + >> + priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL); >> + if (!priv) { >> + dev_err(host->dev, "mem alloc failed for private data\n"); >> + return -ENOMEM; >> + } >> + host->priv = priv; >> + >> + of_property_for_each_u32(node, "clock-freq-table", prop, cur, val) { >> + if (num >= MAX_NUMS) >> + break; >> + priv->clk_table[num++] = val; >> + } >> + return 0; >> +} > > If we make this property part of the generic binding, this function could > also get moved to the main dw_mci driver. > >> +static int dw_mci_k3_suspend(struct device *dev) >> +{ >> + struct dw_mci *host = dev_get_drvdata(dev); >> + int ret = 0; >> + >> + ret = dw_mci_suspend(host); > > You should never initialize local variables when they are set later in the > function (the ret = 0 part above). For more complex functions, this prevents > gcc from warning you about accidentally uninitialized uses. > >> + if (!ret) >> + clk_disable_unprepare(host->ciu_clk); >> + >> + return ret; >> +} > > The suspend/resume code also looks very generic. Can't we make these the > default for dw-mci? If you do both, you won't even need a k3 specific driver. > I think in general we should try hard to add code like this to the common > driver when there is a chance that it can be shared with other platforms. Dw-mmc has the LOW_POWER mode feature at CLKENA register, this feature is running like clock-gating. So i have known it didn't control clock enable/disable in dw-mmc.c. Best Regards, Jaehoon Chung > > Arnd > -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Mon, Dec 30, 2013 at 7:55 AM, Jaehoon Chung <jh80.chung@samsung.com> wrote: > On 12/30/2013 06:05 AM, Arnd Bergmann wrote: >> On Saturday 28 December 2013, Zhangfei Gao wrote: >>> Add dw_mmc-k3.c for k3v2, support sd/emmc >>> >>> Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org> >>> Signed-off-by: Zhigang Wang <brooke.wangzhigang@huawei.com> >>> --- >>> .../devicetree/bindings/mmc/k3-dw-mshc.txt | 60 ++++++++++ >>> drivers/mmc/host/Kconfig | 10 ++ >>> drivers/mmc/host/Makefile | 1 + >>> drivers/mmc/host/dw_mmc-k3.c | 126 ++++++++++++++++++++ >>> 4 files changed, 197 insertions(+) >>> create mode 100644 Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt >>> create mode 100644 drivers/mmc/host/dw_mmc-k3.c >>> >>> diff --git a/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt >>> new file mode 100644 >>> index 000000000000..d7e2d7f159bb >>> --- /dev/null >>> +++ b/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt >>> @@ -0,0 +1,60 @@ >>> +* Hisilicon specific extensions to the Synopsys Designware Mobile >>> + Storage Host Controller >>> + >>> +Read synopsys-dw-mshc.txt for more details >>> + >>> +The Synopsys designware mobile storage host controller is used to interface >>> +a SoC with storage medium such as eMMC or SD/MMC cards. This file documents >>> +differences between the core Synopsys dw mshc controller properties described >>> +by synopsys-dw-mshc.txt and the properties used by the Hisilicon specific >>> +extensions to the Synopsys Designware Mobile Storage Host Controller. >>> + >>> +Required Properties: >>> + >>> +* compatible: should be one of the following. >>> + - "hisilicon,hi4511-dw-mshc": for controllers with hi4511 specific extentions. >> >> I wonder if this is actually a different variant of the mshc hardware, or just >> wired up in a different way. Do you know details? >> >> Since the only difference in the binding is the presence of the "clock-freq-table" >> property, we could also make this property generic for the mshc driver and use >> it if present but fall back to the normal behavior when it is absent. There are still other differences and limitations besides "clock-freq-table". The controller seems less intelligent than other Synopsys mmc controller. The tuning process like HS200 is not intelligent, as a result, some local registers are added to help this. >> >>> +* clock-freq-table: should be the frequency (in Hz) array of the ciu clock >>> + in each supported mode. >>> + 0. CIU clock rate in Hz for DS mode >>> + 1. CIU clock rate in Hz for MMC HS mode >>> + 2. CIU clock rate in Hz for SD HS mode >>> + 3. CIU clock rate in Hz for SDR12 mode >>> + 4. CIU clock rate in Hz for SDR25 mode >>> + 5. CIU clock rate in Hz for SDR50 mode >>> + 6. CIU clock rate in Hz for SDR104 mode >>> + 7. CIU clock rate in Hz for DDR50 mode >>> + 8. CIU clock rate in Hz for HS200 mode >> >> This looks god now. >> >>> +static void dw_mci_k3_set_ios(struct dw_mci *host, struct mmc_ios *ios) >>> +{ >>> + struct dw_mci_k3_priv_data *priv = host->priv; >>> + u32 rate = priv->clk_table[ios->timing]; >>> + int ret; >> >> I think this should have some range checking to see if the mode that is >> being set had a clock frequency set in the DT. The range safety should be ensured by the clk_table array, MAX_NUMS=10. >> >>> + >>> + ret = clk_set_rate(host->ciu_clk, rate); >>> + if (ret) >>> + dev_warn(host->dev, "failed to set clock rate %uHz\n", rate); >>> + >>> + host->bus_hz = clk_get_rate(host->ciu_clk); >>> +} >> >> Why do you call clk_get_rate() here, shouldn't it always be the same >> rate that you have just set? It is more accurate to use clk_get_rate here. For example, if switch to ios->clock as you suggested before, 52M will be set for mmc, while 50M is supported. However, it can simply use rate set currently. >> >>> +static int dw_mci_k3_parse_dt(struct dw_mci *host) >>> +{ >>> + struct dw_mci_k3_priv_data *priv; >>> + struct device_node *node = host->dev->of_node; >>> + struct property *prop; >>> + const __be32 *cur; >>> + u32 val, num = 0; >>> + >>> + priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL); >>> + if (!priv) { >>> + dev_err(host->dev, "mem alloc failed for private data\n"); >>> + return -ENOMEM; >>> + } >>> + host->priv = priv; >>> + >>> + of_property_for_each_u32(node, "clock-freq-table", prop, cur, val) { >>> + if (num >= MAX_NUMS) >>> + break; >>> + priv->clk_table[num++] = val; >>> + } >>> + return 0; >>> +} >> >> If we make this property part of the generic binding, this function could >> also get moved to the main dw_mci driver. This may be not general. The controller does not generate the clock itself, and set rate to the outside clock source, which may be different according to the working mode. >> >>> +static int dw_mci_k3_suspend(struct device *dev) >>> +{ >>> + struct dw_mci *host = dev_get_drvdata(dev); >>> + int ret = 0; >>> + >>> + ret = dw_mci_suspend(host); >> >> You should never initialize local variables when they are set later in the >> function (the ret = 0 part above). For more complex functions, this prevents >> gcc from warning you about accidentally uninitialized uses. Frankly speaking, I didn't know this rule at all. Often see the warning before like “Variable to be used not initialized”, so preferred to init the local variable as much as possible. Looks like it is wrong. >> >>> + if (!ret) >>> + clk_disable_unprepare(host->ciu_clk); >>> + >>> + return ret; >>> +} >> >> The suspend/resume code also looks very generic. Can't we make these the >> default for dw-mci? If you do both, you won't even need a k3 specific driver. >> I think in general we should try hard to add code like this to the common >> driver when there is a chance that it can be shared with other platforms. > > Dw-mmc has the LOW_POWER mode feature at CLKENA register, > this feature is running like clock-gating. > So i have known it didn't control clock enable/disable in dw-mmc.c. It is added here since we have to set special register when resume back, which has been abstracted to ciu_clk prepare operation. > > Best Regards, > Jaehoon Chung > >> >> Arnd >> > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 12/30/2013 10:32 AM, Zhangfei Gao wrote: > On Mon, Dec 30, 2013 at 7:55 AM, Jaehoon Chung <jh80.chung@samsung.com> wrote: >> On 12/30/2013 06:05 AM, Arnd Bergmann wrote: >>> On Saturday 28 December 2013, Zhangfei Gao wrote: >>>> Add dw_mmc-k3.c for k3v2, support sd/emmc >>>> >>>> Signed-off-by: Zhangfei Gao <zhangfei.gao@linaro.org> >>>> Signed-off-by: Zhigang Wang <brooke.wangzhigang@huawei.com> >>>> --- >>>> .../devicetree/bindings/mmc/k3-dw-mshc.txt | 60 ++++++++++ >>>> drivers/mmc/host/Kconfig | 10 ++ >>>> drivers/mmc/host/Makefile | 1 + >>>> drivers/mmc/host/dw_mmc-k3.c | 126 ++++++++++++++++++++ >>>> 4 files changed, 197 insertions(+) >>>> create mode 100644 Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt >>>> create mode 100644 drivers/mmc/host/dw_mmc-k3.c >>>> >>>> diff --git a/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt >>>> new file mode 100644 >>>> index 000000000000..d7e2d7f159bb >>>> --- /dev/null >>>> +++ b/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt >>>> @@ -0,0 +1,60 @@ >>>> +* Hisilicon specific extensions to the Synopsys Designware Mobile >>>> + Storage Host Controller >>>> + >>>> +Read synopsys-dw-mshc.txt for more details >>>> + >>>> +The Synopsys designware mobile storage host controller is used to interface >>>> +a SoC with storage medium such as eMMC or SD/MMC cards. This file documents >>>> +differences between the core Synopsys dw mshc controller properties described >>>> +by synopsys-dw-mshc.txt and the properties used by the Hisilicon specific >>>> +extensions to the Synopsys Designware Mobile Storage Host Controller. >>>> + >>>> +Required Properties: >>>> + >>>> +* compatible: should be one of the following. >>>> + - "hisilicon,hi4511-dw-mshc": for controllers with hi4511 specific extentions. >>> >>> I wonder if this is actually a different variant of the mshc hardware, or just >>> wired up in a different way. Do you know details? >>> >>> Since the only difference in the binding is the presence of the "clock-freq-table" >>> property, we could also make this property generic for the mshc driver and use >>> it if present but fall back to the normal behavior when it is absent. > > There are still other differences and limitations besides "clock-freq-table". > The controller seems less intelligent than other Synopsys mmc controller. > The tuning process like HS200 is not intelligent, as a result, some > local registers are added to help this. > >>> >>>> +* clock-freq-table: should be the frequency (in Hz) array of the ciu clock >>>> + in each supported mode. >>>> + 0. CIU clock rate in Hz for DS mode >>>> + 1. CIU clock rate in Hz for MMC HS mode >>>> + 2. CIU clock rate in Hz for SD HS mode >>>> + 3. CIU clock rate in Hz for SDR12 mode >>>> + 4. CIU clock rate in Hz for SDR25 mode >>>> + 5. CIU clock rate in Hz for SDR50 mode >>>> + 6. CIU clock rate in Hz for SDR104 mode >>>> + 7. CIU clock rate in Hz for DDR50 mode >>>> + 8. CIU clock rate in Hz for HS200 mode >>> >>> This looks god now. >>> >>>> +static void dw_mci_k3_set_ios(struct dw_mci *host, struct mmc_ios *ios) >>>> +{ >>>> + struct dw_mci_k3_priv_data *priv = host->priv; >>>> + u32 rate = priv->clk_table[ios->timing]; >>>> + int ret; >>> >>> I think this should have some range checking to see if the mode that is >>> being set had a clock frequency set in the DT. > > The range safety should be ensured by the clk_table array, MAX_NUMS=10. >>> >>>> + >>>> + ret = clk_set_rate(host->ciu_clk, rate); >>>> + if (ret) >>>> + dev_warn(host->dev, "failed to set clock rate %uHz\n", rate); >>>> + >>>> + host->bus_hz = clk_get_rate(host->ciu_clk); >>>> +} >>> >>> Why do you call clk_get_rate() here, shouldn't it always be the same >>> rate that you have just set? > > It is more accurate to use clk_get_rate here. > For example, if switch to ios->clock as you suggested before, 52M will > be set for mmc, while 50M is supported. > However, it can simply use rate set currently. > >>> >>>> +static int dw_mci_k3_parse_dt(struct dw_mci *host) >>>> +{ >>>> + struct dw_mci_k3_priv_data *priv; >>>> + struct device_node *node = host->dev->of_node; >>>> + struct property *prop; >>>> + const __be32 *cur; >>>> + u32 val, num = 0; >>>> + >>>> + priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL); >>>> + if (!priv) { >>>> + dev_err(host->dev, "mem alloc failed for private data\n"); >>>> + return -ENOMEM; >>>> + } >>>> + host->priv = priv; >>>> + >>>> + of_property_for_each_u32(node, "clock-freq-table", prop, cur, val) { >>>> + if (num >= MAX_NUMS) >>>> + break; >>>> + priv->clk_table[num++] = val; >>>> + } >>>> + return 0; >>>> +} >>> >>> If we make this property part of the generic binding, this function could >>> also get moved to the main dw_mci driver. > > This may be not general. > The controller does not generate the clock itself, and set rate to the > outside clock source, which may be different according to the working > mode. > >>> >>>> +static int dw_mci_k3_suspend(struct device *dev) >>>> +{ >>>> + struct dw_mci *host = dev_get_drvdata(dev); >>>> + int ret = 0; >>>> + >>>> + ret = dw_mci_suspend(host); >>> >>> You should never initialize local variables when they are set later in the >>> function (the ret = 0 part above). For more complex functions, this prevents >>> gcc from warning you about accidentally uninitialized uses. I am sorry I may fall into the dead end, but still quite not understand this rule. I alwayes thought it would be a good habit to init local variables before. Do you mean it should NOT init local variable as much as possible and only init on demand, like solving the gcc warning. Why not init the them at start in case random value cause unpredicted error? > > Frankly speaking, I didn't know this rule at all. > Often see the warning before like “Variable to be used not initialized”, > so preferred to init the local variable as much as possible. > Looks like it is wrong. > >>> >>>> + if (!ret) >>>> + clk_disable_unprepare(host->ciu_clk); >>>> + >>>> + return ret; >>>> +} >>> >>> The suspend/resume code also looks very generic. Can't we make these the >>> default for dw-mci? If you do both, you won't even need a k3 specific driver. >>> I think in general we should try hard to add code like this to the common >>> driver when there is a chance that it can be shared with other platforms. >> >> Dw-mmc has the LOW_POWER mode feature at CLKENA register, >> this feature is running like clock-gating. >> So i have known it didn't control clock enable/disable in dw-mmc.c. > > It is added here since we have to set special register when resume > back, which has been abstracted to ciu_clk prepare operation. > >> >> Best Regards, >> Jaehoon Chung >> >>> >>> Arnd >>> >> >> >> _______________________________________________ >> linux-arm-kernel mailing list >> linux-arm-kernel@lists.infradead.org >> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Monday 30 December 2013, zhangfei wrote: > >>>> +static int dw_mci_k3_suspend(struct device *dev) > >>>> +{ > >>>> + struct dw_mci *host = dev_get_drvdata(dev); > >>>> + int ret = 0; > >>>> + > >>>> + ret = dw_mci_suspend(host); > >>> > >>> You should never initialize local variables when they are set later in the > >>> function (the ret = 0 part above). For more complex functions, this prevents > >>> gcc from warning you about accidentally uninitialized uses. > > I am sorry I may fall into the dead end, but still quite not understand > this rule. > I alwayes thought it would be a good habit to init local variables before. > Do you mean it should NOT init local variable as much as possible and > only init on demand, like solving the gcc warning. > Why not init the them at start in case random value cause unpredicted error? The gcc warnings are 100% correct, we can use them as a tool to write better code. If you write code that has no warnings with a modern compiler, you will never use random values, but if you always initialize the local variables, you can end up accidentally using '0' where you shouldn't have. See http://rusty.ozlabs.org/?p=232 for an excellent article on the topic by former Linaro assignee Rusty Russell. Arnd -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Dear Arnd, On 12/31/2013 04:27 AM, Arnd Bergmann wrote: > On Monday 30 December 2013, zhangfei wrote: >>>>>> +static int dw_mci_k3_suspend(struct device *dev) >>>>>> +{ >>>>>> + struct dw_mci *host = dev_get_drvdata(dev); >>>>>> + int ret = 0; >>>>>> + >>>>>> + ret = dw_mci_suspend(host); >>>>> >>>>> You should never initialize local variables when they are set later in the >>>>> function (the ret = 0 part above). For more complex functions, this prevents >>>>> gcc from warning you about accidentally uninitialized uses. >> >> I am sorry I may fall into the dead end, but still quite not understand >> this rule. >> I alwayes thought it would be a good habit to init local variables before. >> Do you mean it should NOT init local variable as much as possible and >> only init on demand, like solving the gcc warning. >> Why not init the them at start in case random value cause unpredicted error? > > The gcc warnings are 100% correct, we can use them as a tool to write better > code. If you write code that has no warnings with a modern compiler, you will > never use random values, but if you always initialize the local variables, > you can end up accidentally using '0' where you shouldn't have. > > See http://rusty.ozlabs.org/?p=232 for an excellent article on the topic > by former Linaro assignee Rusty Russell. > Excellent, this is what I am looking for. Thanks for the patience. I may need some time and gradually change the habit to diminish the hurt memory caused by uninitialized vector. Will update and take care latter. By the way, are you fine with the other comments' explanation. Thanks -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Sun, Dec 29, 2013 at 22:05 +0100, Arnd Bergmann wrote: > > On Saturday 28 December 2013, Zhangfei Gao wrote: > > > +static void dw_mci_k3_set_ios(struct dw_mci *host, struct mmc_ios *ios) > > +{ > > + struct dw_mci_k3_priv_data *priv = host->priv; > > + u32 rate = priv->clk_table[ios->timing]; > > + int ret; > > [ ... ] > > > + > > + ret = clk_set_rate(host->ciu_clk, rate); > > + if (ret) > > + dev_warn(host->dev, "failed to set clock rate %uHz\n", rate); > > + > > + host->bus_hz = clk_get_rate(host->ciu_clk); > > +} > > Why do you call clk_get_rate() here, shouldn't it always be the same > rate that you have just set? Not necessarily. What you pass to clk_set_rate() is the rate/frequency that you _want_, while what you get from clk_get_rate() is the rate you _got_ taking the specific input clock rate and the available sets of multipliers/dividers into consideration. Both values should be similar (roughly the same), but they need not be identical. The order of the difference depends on the granularity of the hardware dividers or whether PLLs are used. So, re-fetching the resulting rate after setting up a desired rate actually better reflects the status-quo for diagnostics or for subsequent processing. virtually yours Gerhard Sittig
On 12/31/2013 09:20 PM, Gerhard Sittig wrote: > On Sun, Dec 29, 2013 at 22:05 +0100, Arnd Bergmann wrote: >> >> On Saturday 28 December 2013, Zhangfei Gao wrote: >> >>> +static void dw_mci_k3_set_ios(struct dw_mci *host, struct mmc_ios *ios) >>> +{ >>> + struct dw_mci_k3_priv_data *priv = host->priv; >>> + u32 rate = priv->clk_table[ios->timing]; >>> + int ret; >> >> [ ... ] >> >>> + >>> + ret = clk_set_rate(host->ciu_clk, rate); >>> + if (ret) >>> + dev_warn(host->dev, "failed to set clock rate %uHz\n", rate); >>> + >>> + host->bus_hz = clk_get_rate(host->ciu_clk); >>> +} >> >> Why do you call clk_get_rate() here, shouldn't it always be the same >> rate that you have just set? > > Not necessarily. What you pass to clk_set_rate() is the > rate/frequency that you _want_, while what you get from > clk_get_rate() is the rate you _got_ taking the specific input > clock rate and the available sets of multipliers/dividers into > consideration. Both values should be similar (roughly the same), > but they need not be identical. The order of the difference > depends on the granularity of the hardware dividers or whether > PLLs are used. > > So, re-fetching the resulting rate after setting up a desired > rate actually better reflects the status-quo for diagnostics or > for subsequent processing. Thanks Gerhard for the professional explanation. -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt b/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt new file mode 100644 index 000000000000..d7e2d7f159bb --- /dev/null +++ b/Documentation/devicetree/bindings/mmc/k3-dw-mshc.txt @@ -0,0 +1,60 @@ +* Hisilicon specific extensions to the Synopsys Designware Mobile + Storage Host Controller + +Read synopsys-dw-mshc.txt for more details + +The Synopsys designware mobile storage host controller is used to interface +a SoC with storage medium such as eMMC or SD/MMC cards. This file documents +differences between the core Synopsys dw mshc controller properties described +by synopsys-dw-mshc.txt and the properties used by the Hisilicon specific +extensions to the Synopsys Designware Mobile Storage Host Controller. + +Required Properties: + +* compatible: should be one of the following. + - "hisilicon,hi4511-dw-mshc": for controllers with hi4511 specific extentions. + +* clock-freq-table: should be the frequency (in Hz) array of the ciu clock + in each supported mode. + 0. CIU clock rate in Hz for DS mode + 1. CIU clock rate in Hz for MMC HS mode + 2. CIU clock rate in Hz for SD HS mode + 3. CIU clock rate in Hz for SDR12 mode + 4. CIU clock rate in Hz for SDR25 mode + 5. CIU clock rate in Hz for SDR50 mode + 6. CIU clock rate in Hz for SDR104 mode + 7. CIU clock rate in Hz for DDR50 mode + 8. CIU clock rate in Hz for HS200 mode + +Example: + + /* for Hi3620 */ + + /* SoC portion */ + dwmmc_0: dwmmc0@fcd03000 { + compatible = "hisilicon,hi4511-dw-mshc"; + reg = <0xfcd03000 0x1000>; + interrupts = <0 16 4>; + #address-cells = <1>; + #size-cells = <0>; + clocks = <&mmc_clock HI3620_SD_CIUCLK>, <&clock HI3620_DDRC_PER_CLK>; + clock-names = "ciu", "biu"; + clock-freq-table = + <25000000 0 50000000 25000000 50000000 100000000 0 50000000>; + }; + + /* Board portion */ + dwmmc0@fcd03000 { + num-slots = <1>; + vmmc-supply = <&ldo12>; + fifo-depth = <0x100>; + supports-highspeed; + pinctrl-names = "default"; + pinctrl-0 = <&sd_pmx_pins &sd_cfg_func1 &sd_cfg_func2>; + slot@0 { + reg = <0>; + bus-width = <4>; + disable-wp; + cd-gpios = <&gpio10 3 0>; + }; + }; diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig index 7fc5099e44b2..45aaa2de0f58 100644 --- a/drivers/mmc/host/Kconfig +++ b/drivers/mmc/host/Kconfig @@ -575,6 +575,16 @@ config MMC_DW_SOCFPGA This selects support for Altera SoCFPGA specific extensions to the Synopsys DesignWare Memory Card Interface driver. +config MMC_DW_K3 + tristate "K3 specific extensions for Synopsys DW Memory Card Interface" + depends on MMC_DW + select MMC_DW_PLTFM + select MMC_DW_IDMAC + help + This selects support for Hisilicon K3 SoC specific extensions to the + Synopsys DesignWare Memory Card Interface driver. Select this option + for platforms based on Hisilicon K3 SoC's. + config MMC_DW_PCI tristate "Synopsys Designware MCI support on PCI bus" depends on MMC_DW && PCI diff --git a/drivers/mmc/host/Makefile b/drivers/mmc/host/Makefile index c41d0c364509..64f5f8d35839 100644 --- a/drivers/mmc/host/Makefile +++ b/drivers/mmc/host/Makefile @@ -43,6 +43,7 @@ obj-$(CONFIG_MMC_DW) += dw_mmc.o obj-$(CONFIG_MMC_DW_PLTFM) += dw_mmc-pltfm.o obj-$(CONFIG_MMC_DW_EXYNOS) += dw_mmc-exynos.o obj-$(CONFIG_MMC_DW_SOCFPGA) += dw_mmc-socfpga.o +obj-$(CONFIG_MMC_DW_K3) += dw_mmc-k3.o obj-$(CONFIG_MMC_DW_PCI) += dw_mmc-pci.o obj-$(CONFIG_MMC_SH_MMCIF) += sh_mmcif.o obj-$(CONFIG_MMC_JZ4740) += jz4740_mmc.o diff --git a/drivers/mmc/host/dw_mmc-k3.c b/drivers/mmc/host/dw_mmc-k3.c new file mode 100644 index 000000000000..89f69428e3dc --- /dev/null +++ b/drivers/mmc/host/dw_mmc-k3.c @@ -0,0 +1,126 @@ +/* + * Copyright (c) 2013 Linaro Ltd. + * Copyright (c) 2013 Hisilicon Limited. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + */ + +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/clk.h> +#include <linux/mmc/host.h> +#include <linux/mmc/dw_mmc.h> +#include <linux/of_address.h> + +#include "dw_mmc.h" +#include "dw_mmc-pltfm.h" + +#define MAX_NUMS 10 +struct dw_mci_k3_priv_data { + u32 clk_table[MAX_NUMS]; +}; + +static void dw_mci_k3_set_ios(struct dw_mci *host, struct mmc_ios *ios) +{ + struct dw_mci_k3_priv_data *priv = host->priv; + u32 rate = priv->clk_table[ios->timing]; + int ret; + + ret = clk_set_rate(host->ciu_clk, rate); + if (ret) + dev_warn(host->dev, "failed to set clock rate %uHz\n", rate); + + host->bus_hz = clk_get_rate(host->ciu_clk); +} + +static int dw_mci_k3_parse_dt(struct dw_mci *host) +{ + struct dw_mci_k3_priv_data *priv; + struct device_node *node = host->dev->of_node; + struct property *prop; + const __be32 *cur; + u32 val, num = 0; + + priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) { + dev_err(host->dev, "mem alloc failed for private data\n"); + return -ENOMEM; + } + host->priv = priv; + + of_property_for_each_u32(node, "clock-freq-table", prop, cur, val) { + if (num >= MAX_NUMS) + break; + priv->clk_table[num++] = val; + } + return 0; +} + +static const struct dw_mci_drv_data k3_drv_data = { + .set_ios = dw_mci_k3_set_ios, + .parse_dt = dw_mci_k3_parse_dt, +}; + +static const struct of_device_id dw_mci_k3_match[] = { + { .compatible = "hisilicon,hi4511-dw-mshc", .data = &k3_drv_data, }, + {}, +}; +MODULE_DEVICE_TABLE(of, dw_mci_k3_match); + +static int dw_mci_k3_probe(struct platform_device *pdev) +{ + const struct dw_mci_drv_data *drv_data; + const struct of_device_id *match; + + match = of_match_node(dw_mci_k3_match, pdev->dev.of_node); + drv_data = match->data; + + return dw_mci_pltfm_register(pdev, drv_data); +} + +static int dw_mci_k3_suspend(struct device *dev) +{ + struct dw_mci *host = dev_get_drvdata(dev); + int ret = 0; + + ret = dw_mci_suspend(host); + if (!ret) + clk_disable_unprepare(host->ciu_clk); + + return ret; +} + +static int dw_mci_k3_resume(struct device *dev) +{ + struct dw_mci *host = dev_get_drvdata(dev); + int ret = 0; + + ret = clk_prepare_enable(host->ciu_clk); + if (ret) { + dev_err(host->dev, "failed to enable ciu clock\n"); + return ret; + } + + return dw_mci_resume(host); +} + +SIMPLE_DEV_PM_OPS(dw_mci_k3_pmops, dw_mci_k3_suspend, dw_mci_k3_resume); + +static struct platform_driver dw_mci_k3_pltfm_driver = { + .probe = dw_mci_k3_probe, + .remove = dw_mci_pltfm_remove, + .driver = { + .name = "dwmmc_k3", + .of_match_table = dw_mci_k3_match, + .pm = &dw_mci_k3_pmops, + }, +}; + +module_platform_driver(dw_mci_k3_pltfm_driver); + +MODULE_DESCRIPTION("K3 Specific DW-MSHC Driver Extension"); +MODULE_LICENSE("GPL v2"); +MODULE_ALIAS("platform:dwmmc-k3");