| Message ID | e455d98df0fba37e8b7ecd7e72d510a05f23d2ba.1349778821.git.vipin.kumar@st.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 16:14 Tue 09 Oct , Vipin Kumar wrote: > The NAND devices have a ready/busy (active low) output which is connected to the > FSMC controller FSMC_RnB pin > > The CPU can work in following two ways > * CPU keeps waiting for a ready response and it halts until it receives a ready > response from NAND device. This halts the ldr instruction in between and in > effect holds the CPU down for a number of cycles. During this period, CPU > can't even service interrupts. This behavior is enabled via WAIT_ON bit of > FSMC controller > * CPU merely issues the command and does not wait for response. The NAND device > is later probed for being ready by reading the NAND_RnB signal > > Until now, WAIT_ON was enabled by default. This patch implements reading the > device ready state through a gpio. The gpio number is passed via DT and this > patch also adds a corresponding binding for fsmc > > Signed-off-by: Vipin Kumar <vipin.kumar@st.com> > --- > .../devicetree/bindings/mtd/fsmc-nand.txt | 5 ++ > drivers/mtd/nand/fsmc_nand.c | 54 +++++++++++++++++++--- > include/linux/mtd/fsmc.h | 11 +++++ > 3 files changed, 64 insertions(+), 6 deletions(-) > > diff --git a/Documentation/devicetree/bindings/mtd/fsmc-nand.txt b/Documentation/devicetree/bindings/mtd/fsmc-nand.txt > index 6a7fc43..598bca2 100644 > --- a/Documentation/devicetree/bindings/mtd/fsmc-nand.txt > +++ b/Documentation/devicetree/bindings/mtd/fsmc-nand.txt > @@ -25,6 +25,11 @@ Optional properties: > period of hclk ie a number 4 in thold with hclk = 166MHz means that > thold = (1000 / 166) * 4 ns = 24.09ns > > +- st,ready-busy: Should contain either of "rb-gpio" or "rb-wait". When > + this property is not defined, the default is to use rb-wait. > +- st,rb-gpios: When the st,ready-busy is defined as "rb-gpio", a gpio > + pin number is defined in this property > + > Example: > > fsmc: flash@d1800000 { > diff --git a/drivers/mtd/nand/fsmc_nand.c b/drivers/mtd/nand/fsmc_nand.c > index f3d69b3..eaffd3b 100644 > --- a/drivers/mtd/nand/fsmc_nand.c > +++ b/drivers/mtd/nand/fsmc_nand.c > @@ -22,6 +22,7 @@ > #include <linux/dma-direction.h> > #include <linux/dma-mapping.h> > #include <linux/err.h> > +#include <linux/gpio.h> > #include <linux/init.h> > #include <linux/module.h> > #include <linux/resource.h> > @@ -32,6 +33,7 @@ > #include <linux/mtd/nand_ecc.h> > #include <linux/platform_device.h> > #include <linux/of.h> > +#include <linux/of_gpio.h> > #include <linux/mtd/partitions.h> > #include <linux/io.h> > #include <linux/slab.h> > @@ -289,6 +291,7 @@ static struct fsmc_eccplace fsmc_ecc4_sp_place = { > * @write_dma_chan: DMA channel for write access to NAND > * @dma_access_complete: Completion structure > * > + * @rb_pin: Ready/Busy data > * @dev_timings: Timings to be programmed in controller > * @partitions: Partition info for a NAND Flash > * @nr_partitions: Total number of partition of a NAND flash > @@ -322,6 +325,7 @@ struct fsmc_nand_data { > struct completion dma_access_complete; > > /* Recieved from plat data */ > + struct fsmc_rbpin *rbpin; > struct fsmc_nand_timings *dev_timings; > struct mtd_partition *partitions; > unsigned int nr_partitions; > @@ -410,12 +414,16 @@ static void fsmc_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl) > * This routine initializes timing parameters related to NAND memory access in > * FSMC registers > */ > -static void fsmc_nand_setup(void __iomem *regs, uint32_t bank, > - uint32_t busw, struct fsmc_nand_timings *timings) > +static void fsmc_nand_setup(void __iomem *regs, uint32_t bank, uint32_t busw, > + struct fsmc_nand_timings *timings, > + struct fsmc_rbpin *rbpin) > { > - uint32_t value = FSMC_DEVTYPE_NAND | FSMC_ENABLE | FSMC_WAITON; > + uint32_t value = FSMC_DEVTYPE_NAND | FSMC_ENABLE; > uint32_t tclr, tar, thiz, thold, twait, tset; > > + if (!rbpin || (rbpin->use_pin == FSMC_RB_WAIT)) > + value |= FSMC_WAITON; > + > tclr = (timings->tclr & FSMC_TCLR_MASK) << FSMC_TCLR_SHIFT; > tar = (timings->tar & FSMC_TAR_MASK) << FSMC_TAR_SHIFT; > thiz = (timings->thiz & FSMC_THIZ_MASK) << FSMC_THIZ_SHIFT; > @@ -857,6 +865,14 @@ static bool filter(struct dma_chan *chan, void *slave) > return true; > } > > +static int fsmc_dev_ready(struct mtd_info *mtd) > +{ > + struct fsmc_nand_data *host = container_of(mtd, > + struct fsmc_nand_data, mtd); > + > + return !!gpio_get_value(host->rbpin->gpio_pin); > +} > + > #ifdef CONFIG_OF > static int __devinit fsmc_nand_probe_config_dt(struct platform_device *pdev, > struct device_node *np) > @@ -870,7 +886,9 @@ static int __devinit fsmc_nand_probe_config_dt(struct platform_device *pdev, > .twait = FSMC_TWAIT_6, > .tset = FSMC_TSET_0, > }; > + const char *rb; > u32 val; > + enum of_gpio_flags flags; > > /* Set default NAND width to 8 bits */ > pdata->width = 8; > @@ -911,6 +929,14 @@ static int __devinit fsmc_nand_probe_config_dt(struct platform_device *pdev, > sizeof(default_timings)); > } > > + if (!of_property_read_string(np, "st,ready-busy", &rb) && > + !strcmp(rb, "rb-gpio")) { > + pdata->rbpin.use_pin = FSMC_RB_GPIO; > + pdata->rbpin.gpio_pin = > + of_get_named_gpio_flags(np, "st,rb-gpios", 0, &flags); > + } else > + pdata->rbpin.use_pin = FSMC_RB_WAIT; > + > return 0; > } > #else > @@ -1049,6 +1075,8 @@ static int __init fsmc_nand_probe(struct platform_device *pdev) > host->nr_partitions = pdata->nr_partitions; > host->dev = &pdev->dev; > host->dev_timings = &pdata->nand_timings; > + host->rbpin = &pdata->rbpin; > + > host->mode = pdata->mode; > host->max_banks = pdata->max_banks; > > @@ -1074,6 +1102,18 @@ static int __init fsmc_nand_probe(struct platform_device *pdev) > nand->select_chip = fsmc_select_chip; > nand->badblockbits = 7; > > + if (host->rbpin->use_pin != FSMC_RB_WAIT) > + nand->dev_ready = fsmc_dev_ready; > + > + if (host->rbpin->use_pin == FSMC_RB_GPIO) { > + ret = gpio_request(host->rbpin->gpio_pin, "fsmc-rb"); > + if (ret < 0) { > + dev_err(&pdev->dev, "gpio request fail: %d\n", > + host->rbpin->gpio_pin); > + goto err_gpio_req; > + } > + } > + > if (pdata->width == FSMC_NAND_BW16) > nand->options |= NAND_BUSWIDTH_16; > > @@ -1107,7 +1147,7 @@ static int __init fsmc_nand_probe(struct platform_device *pdev) > for (bank = 0; bank < host->max_banks; bank++) > fsmc_nand_setup(host->regs_va, bank, > nand->options & NAND_BUSWIDTH_16, > - host->dev_timings); > + host->dev_timings, host->rbpin); > > if (AMBA_REV_BITS(host->pid) >= 8) { > nand->ecc.read_page = fsmc_read_page_hwecc; > @@ -1211,6 +1251,9 @@ err_req_write_chnl: > if (host->mode == USE_DMA_ACCESS) > dma_release_channel(host->read_dma_chan); > err_req_read_chnl: > + if (host->rbpin->use_pin == FSMC_RB_GPIO) > + gpio_free(host->rbpin->gpio_pin); > +err_gpio_req: > clk_disable_unprepare(host->clk); > err_clk_prepare_enable: > clk_put(host->clk); > @@ -1260,8 +1303,7 @@ static int fsmc_nand_resume(struct device *dev) > for (bank = 0; bank < host->max_banks; bank++) > fsmc_nand_setup(host->regs_va, bank, > host->nand.options & NAND_BUSWIDTH_16, > - host->dev_timings); > - > + host->dev_timings, host->rbpin); > } > return 0; > } > diff --git a/include/linux/mtd/fsmc.h b/include/linux/mtd/fsmc.h > index 4fbdce4..eed22a1 100644 > --- a/include/linux/mtd/fsmc.h > +++ b/include/linux/mtd/fsmc.h > @@ -130,6 +130,16 @@ struct fsmc_nand_timings { > uint8_t tset; > }; > > +enum rbpin { > + FSMC_RB_WAIT = 0, > + FSMC_RB_GPIO, > +}; > + > +struct fsmc_rbpin { > + enum rbpin use_pin; > + uint32_t gpio_pin; > +}; > + > enum access_mode { > USE_DMA_ACCESS = 1, > USE_WORD_ACCESS, > @@ -149,6 +159,7 @@ enum access_mode { > */ > struct fsmc_nand_platform_data { > struct fsmc_nand_timings nand_timings; > + struct fsmc_rbpin rbpin; do more simple int rbpin; and set it as -EINVAL to use RB_WAIT so in the binding if you do not specifcy a gpio or a valid one we switch to wait Best Regards, J.
On Tue, Oct 9, 2012 at 4:14 PM, Vipin Kumar <vipin.kumar@st.com> wrote: > diff --git a/Documentation/devicetree/bindings/mtd/fsmc-nand.txt b/Documentation/devicetree/bindings/mtd/fsmc-nand.txt > +- st,ready-busy: Should contain either of "rb-gpio" or "rb-wait". When > + this property is not defined, the default is to use rb-wait. > +- st,rb-gpios: When the st,ready-busy is defined as "rb-gpio", a gpio > + pin number is defined in this property Why st,*** maybe fsmc,***? Would be better if you update the example too in this file. > diff --git a/drivers/mtd/nand/fsmc_nand.c b/drivers/mtd/nand/fsmc_nand.c > + * @rb_pin: Ready/Busy data > + struct fsmc_rbpin *rbpin; comment variable mismatch :( > -static void fsmc_nand_setup(void __iomem *regs, uint32_t bank, > - uint32_t busw, struct fsmc_nand_timings *timings) > +static void fsmc_nand_setup(void __iomem *regs, uint32_t bank, uint32_t busw, > + struct fsmc_nand_timings *timings, > + struct fsmc_rbpin *rbpin) Can function prototype come in two lines instead of three? > @@ -1049,6 +1075,8 @@ static int __init fsmc_nand_probe(struct platform_device *pdev) > + if (host->rbpin->use_pin == FSMC_RB_GPIO) { > + ret = gpio_request(host->rbpin->gpio_pin, "fsmc-rb"); > + if (ret < 0) { > + dev_err(&pdev->dev, "gpio request fail: %d\n", > + host->rbpin->gpio_pin); > + goto err_gpio_req; > + } > + } Don't you want to set its direction to input?
diff --git a/Documentation/devicetree/bindings/mtd/fsmc-nand.txt b/Documentation/devicetree/bindings/mtd/fsmc-nand.txt index 6a7fc43..598bca2 100644 --- a/Documentation/devicetree/bindings/mtd/fsmc-nand.txt +++ b/Documentation/devicetree/bindings/mtd/fsmc-nand.txt @@ -25,6 +25,11 @@ Optional properties: period of hclk ie a number 4 in thold with hclk = 166MHz means that thold = (1000 / 166) * 4 ns = 24.09ns +- st,ready-busy: Should contain either of "rb-gpio" or "rb-wait". When + this property is not defined, the default is to use rb-wait. +- st,rb-gpios: When the st,ready-busy is defined as "rb-gpio", a gpio + pin number is defined in this property + Example: fsmc: flash@d1800000 { diff --git a/drivers/mtd/nand/fsmc_nand.c b/drivers/mtd/nand/fsmc_nand.c index f3d69b3..eaffd3b 100644 --- a/drivers/mtd/nand/fsmc_nand.c +++ b/drivers/mtd/nand/fsmc_nand.c @@ -22,6 +22,7 @@ #include <linux/dma-direction.h> #include <linux/dma-mapping.h> #include <linux/err.h> +#include <linux/gpio.h> #include <linux/init.h> #include <linux/module.h> #include <linux/resource.h> @@ -32,6 +33,7 @@ #include <linux/mtd/nand_ecc.h> #include <linux/platform_device.h> #include <linux/of.h> +#include <linux/of_gpio.h> #include <linux/mtd/partitions.h> #include <linux/io.h> #include <linux/slab.h> @@ -289,6 +291,7 @@ static struct fsmc_eccplace fsmc_ecc4_sp_place = { * @write_dma_chan: DMA channel for write access to NAND * @dma_access_complete: Completion structure * + * @rb_pin: Ready/Busy data * @dev_timings: Timings to be programmed in controller * @partitions: Partition info for a NAND Flash * @nr_partitions: Total number of partition of a NAND flash @@ -322,6 +325,7 @@ struct fsmc_nand_data { struct completion dma_access_complete; /* Recieved from plat data */ + struct fsmc_rbpin *rbpin; struct fsmc_nand_timings *dev_timings; struct mtd_partition *partitions; unsigned int nr_partitions; @@ -410,12 +414,16 @@ static void fsmc_cmd_ctrl(struct mtd_info *mtd, int cmd, unsigned int ctrl) * This routine initializes timing parameters related to NAND memory access in * FSMC registers */ -static void fsmc_nand_setup(void __iomem *regs, uint32_t bank, - uint32_t busw, struct fsmc_nand_timings *timings) +static void fsmc_nand_setup(void __iomem *regs, uint32_t bank, uint32_t busw, + struct fsmc_nand_timings *timings, + struct fsmc_rbpin *rbpin) { - uint32_t value = FSMC_DEVTYPE_NAND | FSMC_ENABLE | FSMC_WAITON; + uint32_t value = FSMC_DEVTYPE_NAND | FSMC_ENABLE; uint32_t tclr, tar, thiz, thold, twait, tset; + if (!rbpin || (rbpin->use_pin == FSMC_RB_WAIT)) + value |= FSMC_WAITON; + tclr = (timings->tclr & FSMC_TCLR_MASK) << FSMC_TCLR_SHIFT; tar = (timings->tar & FSMC_TAR_MASK) << FSMC_TAR_SHIFT; thiz = (timings->thiz & FSMC_THIZ_MASK) << FSMC_THIZ_SHIFT; @@ -857,6 +865,14 @@ static bool filter(struct dma_chan *chan, void *slave) return true; } +static int fsmc_dev_ready(struct mtd_info *mtd) +{ + struct fsmc_nand_data *host = container_of(mtd, + struct fsmc_nand_data, mtd); + + return !!gpio_get_value(host->rbpin->gpio_pin); +} + #ifdef CONFIG_OF static int __devinit fsmc_nand_probe_config_dt(struct platform_device *pdev, struct device_node *np) @@ -870,7 +886,9 @@ static int __devinit fsmc_nand_probe_config_dt(struct platform_device *pdev, .twait = FSMC_TWAIT_6, .tset = FSMC_TSET_0, }; + const char *rb; u32 val; + enum of_gpio_flags flags; /* Set default NAND width to 8 bits */ pdata->width = 8; @@ -911,6 +929,14 @@ static int __devinit fsmc_nand_probe_config_dt(struct platform_device *pdev, sizeof(default_timings)); } + if (!of_property_read_string(np, "st,ready-busy", &rb) && + !strcmp(rb, "rb-gpio")) { + pdata->rbpin.use_pin = FSMC_RB_GPIO; + pdata->rbpin.gpio_pin = + of_get_named_gpio_flags(np, "st,rb-gpios", 0, &flags); + } else + pdata->rbpin.use_pin = FSMC_RB_WAIT; + return 0; } #else @@ -1049,6 +1075,8 @@ static int __init fsmc_nand_probe(struct platform_device *pdev) host->nr_partitions = pdata->nr_partitions; host->dev = &pdev->dev; host->dev_timings = &pdata->nand_timings; + host->rbpin = &pdata->rbpin; + host->mode = pdata->mode; host->max_banks = pdata->max_banks; @@ -1074,6 +1102,18 @@ static int __init fsmc_nand_probe(struct platform_device *pdev) nand->select_chip = fsmc_select_chip; nand->badblockbits = 7; + if (host->rbpin->use_pin != FSMC_RB_WAIT) + nand->dev_ready = fsmc_dev_ready; + + if (host->rbpin->use_pin == FSMC_RB_GPIO) { + ret = gpio_request(host->rbpin->gpio_pin, "fsmc-rb"); + if (ret < 0) { + dev_err(&pdev->dev, "gpio request fail: %d\n", + host->rbpin->gpio_pin); + goto err_gpio_req; + } + } + if (pdata->width == FSMC_NAND_BW16) nand->options |= NAND_BUSWIDTH_16; @@ -1107,7 +1147,7 @@ static int __init fsmc_nand_probe(struct platform_device *pdev) for (bank = 0; bank < host->max_banks; bank++) fsmc_nand_setup(host->regs_va, bank, nand->options & NAND_BUSWIDTH_16, - host->dev_timings); + host->dev_timings, host->rbpin); if (AMBA_REV_BITS(host->pid) >= 8) { nand->ecc.read_page = fsmc_read_page_hwecc; @@ -1211,6 +1251,9 @@ err_req_write_chnl: if (host->mode == USE_DMA_ACCESS) dma_release_channel(host->read_dma_chan); err_req_read_chnl: + if (host->rbpin->use_pin == FSMC_RB_GPIO) + gpio_free(host->rbpin->gpio_pin); +err_gpio_req: clk_disable_unprepare(host->clk); err_clk_prepare_enable: clk_put(host->clk); @@ -1260,8 +1303,7 @@ static int fsmc_nand_resume(struct device *dev) for (bank = 0; bank < host->max_banks; bank++) fsmc_nand_setup(host->regs_va, bank, host->nand.options & NAND_BUSWIDTH_16, - host->dev_timings); - + host->dev_timings, host->rbpin); } return 0; } diff --git a/include/linux/mtd/fsmc.h b/include/linux/mtd/fsmc.h index 4fbdce4..eed22a1 100644 --- a/include/linux/mtd/fsmc.h +++ b/include/linux/mtd/fsmc.h @@ -130,6 +130,16 @@ struct fsmc_nand_timings { uint8_t tset; }; +enum rbpin { + FSMC_RB_WAIT = 0, + FSMC_RB_GPIO, +}; + +struct fsmc_rbpin { + enum rbpin use_pin; + uint32_t gpio_pin; +}; + enum access_mode { USE_DMA_ACCESS = 1, USE_WORD_ACCESS, @@ -149,6 +159,7 @@ enum access_mode { */ struct fsmc_nand_platform_data { struct fsmc_nand_timings nand_timings; + struct fsmc_rbpin rbpin; struct mtd_partition *partitions; unsigned int nr_partitions; unsigned int options;
The NAND devices have a ready/busy (active low) output which is connected to the FSMC controller FSMC_RnB pin The CPU can work in following two ways * CPU keeps waiting for a ready response and it halts until it receives a ready response from NAND device. This halts the ldr instruction in between and in effect holds the CPU down for a number of cycles. During this period, CPU can't even service interrupts. This behavior is enabled via WAIT_ON bit of FSMC controller * CPU merely issues the command and does not wait for response. The NAND device is later probed for being ready by reading the NAND_RnB signal Until now, WAIT_ON was enabled by default. This patch implements reading the device ready state through a gpio. The gpio number is passed via DT and this patch also adds a corresponding binding for fsmc Signed-off-by: Vipin Kumar <vipin.kumar@st.com> --- .../devicetree/bindings/mtd/fsmc-nand.txt | 5 ++ drivers/mtd/nand/fsmc_nand.c | 54 +++++++++++++++++++--- include/linux/mtd/fsmc.h | 11 +++++ 3 files changed, 64 insertions(+), 6 deletions(-)