Hi Ulf,
On 30/05/14 12:27, Ulf Hansson wrote:
On 28 May 2014 15:48, <srinivas.kandagatla@xxxxxxxxxx> wrote:
...
.f_max = 208000000,
.explicit_mclk_control = true,
+ .qcom_fifo = true,
};
static int mmci_card_busy(struct mmc_host *mmc)
@@ -1006,6 +1009,40 @@ 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)
+{
+ u32 *ptr = (u32 *) buffer;
Instead of u32 ptr above, I suggest to use a char *ptr. You need it
anyway further down below where you move in step of bytes instead of
words.
+ unsigned int count = 0;
+ unsigned int words, bytes;
+ unsigned int fsize = host->variant->fifosize;
+
+ words = remain >> 2;
+ bytes = remain % 4;
+ /* read full words followed by leftover bytes */
+ if (words) {
+ while (readl(host->base + MMCISTATUS) & MCI_RXDATAAVLBL) {
How about while (words && (readl(host->base + MMCISTATUS) & MCI_RXDATAAVLBL)
That would make it possible the remove the "if", both above and below.
That sounds sensible.. I will try it.
+ *ptr = readl(host->base + MMCIFIFO + (count % fsize));
This looks strange. :-) Depending on the count you will read an offset
into the FIFO? Seems like a very awkward implementation of a FIFO in
the HW. :-)
I got into weird issues when I tried using the mmci_pio_read, the fifo
implementation seems to be different. I dont have full details on the
fifo behaviour.
Most of this logic is inherited from 3.4 qcom andriod kernel.
BTW, what does "MCI_RXDATAAVLBL" actually mean for the Qcom variant?
It means, At least 1 word in the RX FIFO. SW can read 1 word only from
the FIFO.
How much data could you expect in the FIFO when this status is
triggered?
Are there no option of reading a number of words, depending on what
type FIFO IRQ that was raised?
There are RXFIFO_HALF_FULL and RXFIFO_FULL bits in status register, but
I never tried to use them. Might be worth a try before I send next
version patches.
I will give a try and keep you posted.
Thanks,
srini
+ ptr++;
+ count += 4;
+ words--;
+ if (!words)
+ break;
+ }
+ }
+
+ if (bytes) {
+ unsigned char buf[4];
+ if (readl(host->base + MMCISTATUS) & MCI_RXDATAAVLBL) {
+ *buf = readl(host->base + MMCIFIFO + (count % fsize));
+ memcpy(ptr, buf, bytes);
+ count += bytes;
+ }
+ }
+
+ return count;
+}
+
Kind regards
Ulf Hansson
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