Intel Baytrail has been observed sometimes to hang
if host controllers are using DMA while deep C-states
are used. Workaround that by specifying a maximum
DMA latency that will prevent deep C-states.
Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
---
drivers/mmc/host/sdhci-pci.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/drivers/mmc/host/sdhci-pci.c b/drivers/mmc/host/sdhci-pci.c
index 5a5b5e9..bba2956 100644
--- a/drivers/mmc/host/sdhci-pci.c
+++ b/drivers/mmc/host/sdhci-pci.c
@@ -330,6 +330,12 @@ static void spt_read_drive_strength(struct sdhci_host *host)
sdhci_pci_spt_drive_strength = 0x10 | ((val >> 12) & 0xf);
}
+static void byt_set_dma_latency(struct sdhci_host *host)
+{
+ host->dma_latency = 20;
+ host->lat_cancel_delay = 275;
+}
+
static int byt_emmc_probe_slot(struct sdhci_pci_slot *slot)
{
slot->host->mmc->caps |= MMC_CAP_8_BIT_DATA | MMC_CAP_NONREMOVABLE |
@@ -338,6 +344,9 @@ static int byt_emmc_probe_slot(struct sdhci_pci_slot *slot)
MMC_CAP_WAIT_WHILE_BUSY;
slot->host->mmc->caps2 |= MMC_CAP2_HC_ERASE_SZ;
slot->hw_reset = sdhci_pci_int_hw_reset;
+ if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_BYT_EMMC ||
+ slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_BYT_EMMC2)
+ byt_set_dma_latency(slot->host);
if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_BSW_EMMC)
slot->host->timeout_clk = 1000; /* 1000 kHz i.e. 1 MHz */
if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_SPT_EMMC) {
@@ -352,6 +361,8 @@ static int byt_sdio_probe_slot(struct sdhci_pci_slot *slot)
slot->host->mmc->caps |= MMC_CAP_POWER_OFF_CARD | MMC_CAP_NONREMOVABLE |
MMC_CAP_BUS_WIDTH_TEST |
MMC_CAP_WAIT_WHILE_BUSY;
+ if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_BYT_SDIO)
+ byt_set_dma_latency(slot->host);
return 0;
}
@@ -362,6 +373,8 @@ static int byt_sd_probe_slot(struct sdhci_pci_slot *slot)
slot->cd_con_id = NULL;
slot->cd_idx = 0;
slot->cd_override_level = true;
+ if (slot->chip->pdev->device == PCI_DEVICE_ID_INTEL_BYT_SD)
+ byt_set_dma_latency(slot->host);
return 0;
}
--
1.9.1
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