| Message ID | 1398759674-13421-1-git-send-email-srinivas.kandagatla@linaro.org |
|---|---|
| State | New |
| Headers | show |
On Tue, Apr 29, 2014 at 10:21 AM, <srinivas.kandagatla@linaro.org> wrote: > From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> > > MCIFIFOCNT register behaviour on Qcom chips is very different than the other > pl180 integrations. MCIFIFOCNT register contains the number of > words that are still waiting to be transferred through the FIFO. It keeps > decrementing once the host CPU reads the MCIFIFO. With the existing logic and > the MCIFIFOCNT behaviour, mmci_pio_read will loop forever, as the FIFOCNT > register will always return transfer size before reading the FIFO. > > Also the data sheet states that "This register is only useful for debug > purposes and should not be used for normal operation since it does not reflect > data which may or may not be in the pipeline". > > This patch implements qcom_pio_read function so as existing mmci_pio_read is > not suitable for Qcom SOCs. > > Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> (...) > +static int mmci_qcom_pio_read(struct mmci_host *host, char *buffer, > + unsigned int remain) > +{ > + uint32_t *ptr = (uint32_t *) buffer; Just use u32 for this. > + int count = 0; > + struct variant_data *variant = host->variant; > + int fifo_size = variant->fifosize; > + > + if (remain % 4) > + remain = ((remain >> 2) + 1) << 2; Explain in a comment exactly what is happening here or noone will understand the code. > + while (readl(host->base + MMCISTATUS) & MCI_RXDATAAVLBL) { > + *ptr = readl(host->base + MMCIFIFO + (count % fifo_size)); > + ptr++; > + count += sizeof(uint32_t); > + remain -= sizeof(uint32_t); sizeof(u32) or just 4 works for these... count += 4; remain -= 4; Is easier to parse and understand I think. > + if (remain == 0) > + break; if (!remain) break; > + } > + return count; > +} > - if (status & MCI_RXACTIVE) > - len = mmci_pio_read(host, buffer, remain); > + if (status & MCI_RXACTIVE) { > + if (host->hw_designer == AMBA_VENDOR_QCOM) > + len = mmci_qcom_pio_read(host, buffer, remain); > + else > + len = mmci_pio_read(host, buffer, remain); > + } Use something like bool qcom_fifo; in vendor data instead. Yours, Linus Walleij -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
On 13/05/14 09:34, Linus Walleij wrote: > On Tue, Apr 29, 2014 at 10:21 AM, <srinivas.kandagatla@linaro.org> wrote: > >> From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> >> >> MCIFIFOCNT register behaviour on Qcom chips is very different than the other >> pl180 integrations. MCIFIFOCNT register contains the number of >> words that are still waiting to be transferred through the FIFO. It keeps >> decrementing once the host CPU reads the MCIFIFO. With the existing logic and >> the MCIFIFOCNT behaviour, mmci_pio_read will loop forever, as the FIFOCNT >> register will always return transfer size before reading the FIFO. >> >> Also the data sheet states that "This register is only useful for debug >> purposes and should not be used for normal operation since it does not reflect >> data which may or may not be in the pipeline". >> >> This patch implements qcom_pio_read function so as existing mmci_pio_read is >> not suitable for Qcom SOCs. >> >> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org> > (...) > >> +static int mmci_qcom_pio_read(struct mmci_host *host, char *buffer, >> + unsigned int remain) >> +{ >> + uint32_t *ptr = (uint32_t *) buffer; > > Just use u32 for this. > >> + int count = 0; >> + struct variant_data *variant = host->variant; >> + int fifo_size = variant->fifosize; >> + >> + if (remain % 4) >> + remain = ((remain >> 2) + 1) << 2; > > Explain in a comment exactly what is happening here or noone will > understand the code. Ok, I will add more comments here. > >> + while (readl(host->base + MMCISTATUS) & MCI_RXDATAAVLBL) { >> + *ptr = readl(host->base + MMCIFIFO + (count % fifo_size)); >> + ptr++; >> + count += sizeof(uint32_t); >> + remain -= sizeof(uint32_t); > > > sizeof(u32) or just 4 works for these... > Yes, Will fix it in next version. > count += 4; > remain -= 4; > > Is easier to parse and understand I think. > >> + if (remain == 0) >> + break; > > if (!remain) > break; > yep. >> + } >> + return count; >> +} > >> - if (status & MCI_RXACTIVE) >> - len = mmci_pio_read(host, buffer, remain); >> + if (status & MCI_RXACTIVE) { >> + if (host->hw_designer == AMBA_VENDOR_QCOM) >> + len = mmci_qcom_pio_read(host, buffer, remain); >> + else >> + len = mmci_pio_read(host, buffer, remain); >> + } > > Use something like bool qcom_fifo; in vendor data instead. > Ok, make sense, I will fix this in next version. --srini > Yours, > Linus Walleij > -- To unsubscribe from this list: send the line "unsubscribe linux-arm-msm" 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/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c index def1b19..45198b6 100644 --- a/drivers/mmc/host/mmci.c +++ b/drivers/mmc/host/mmci.c @@ -1038,6 +1038,29 @@ mmci_cmd_irq(struct mmci_host *host, struct mmc_command *cmd, } } +static int mmci_qcom_pio_read(struct mmci_host *host, char *buffer, + unsigned int remain) +{ + uint32_t *ptr = (uint32_t *) buffer; + int count = 0; + struct variant_data *variant = host->variant; + int fifo_size = variant->fifosize; + + if (remain % 4) + remain = ((remain >> 2) + 1) << 2; + + while (readl(host->base + MMCISTATUS) & MCI_RXDATAAVLBL) { + *ptr = readl(host->base + MMCIFIFO + (count % fifo_size)); + ptr++; + count += sizeof(uint32_t); + + remain -= sizeof(uint32_t); + if (remain == 0) + break; + } + return count; +} + static int mmci_pio_read(struct mmci_host *host, char *buffer, unsigned int remain) { void __iomem *base = host->base; @@ -1159,8 +1182,12 @@ static irqreturn_t mmci_pio_irq(int irq, void *dev_id) remain = sg_miter->length; len = 0; - if (status & MCI_RXACTIVE) - len = mmci_pio_read(host, buffer, remain); + if (status & MCI_RXACTIVE) { + if (host->hw_designer == AMBA_VENDOR_QCOM) + len = mmci_qcom_pio_read(host, buffer, remain); + else + len = mmci_pio_read(host, buffer, remain); + } if (status & MCI_TXACTIVE) len = mmci_pio_write(host, buffer, remain, status);