On 13/05/14 09:34, Linus Walleij wrote:
On Tue, Apr 29, 2014 at 10:21 AM, <srinivas.kandagatla@xxxxxxxxxx> wrote:
From: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
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@xxxxxxxxxx>
(...)
+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
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