[PATCH v5 4/5] mmc: sdhci-tegra: Implement alternative_gpt_sector()

[Dmitry Osipenko <digetx@gmail.com>]

Tegra20/30/114/124 Android devices place GPT at a non-standard location.
Implement alternative_gpt_sector() callback of the MMC host ops which
specifies that GPT location for the partition scanner.

Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
 drivers/mmc/host/sdhci-tegra.c | 42 ++++++++++++++++++++++++++++++++++
 1 file changed, 42 insertions(+)

diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
index 387ce9cdbd7c..24a713689d5b 100644
--- a/drivers/mmc/host/sdhci-tegra.c
+++ b/drivers/mmc/host/sdhci-tegra.c
@@ -116,6 +116,8 @@
  */
 #define NVQUIRK_HAS_TMCLK				BIT(10)
 
+#define NVQUIRK_HAS_ANDROID_GPT_SECTOR			BIT(11)
+
 /* SDMMC CQE Base Address for Tegra Host Ver 4.1 and Higher */
 #define SDHCI_TEGRA_CQE_BASE_ADDR			0xF000
 
@@ -1361,6 +1363,7 @@ static const struct sdhci_tegra_soc_data soc_data_tegra20 = {
 	.pdata = &sdhci_tegra20_pdata,
 	.dma_mask = DMA_BIT_MASK(32),
 	.nvquirks = NVQUIRK_FORCE_SDHCI_SPEC_200 |
+		    NVQUIRK_HAS_ANDROID_GPT_SECTOR |
 		    NVQUIRK_ENABLE_BLOCK_GAP_DET,
 };
 
@@ -1390,6 +1393,7 @@ static const struct sdhci_tegra_soc_data soc_data_tegra30 = {
 	.nvquirks = NVQUIRK_ENABLE_SDHCI_SPEC_300 |
 		    NVQUIRK_ENABLE_SDR50 |
 		    NVQUIRK_ENABLE_SDR104 |
+		    NVQUIRK_HAS_ANDROID_GPT_SECTOR |
 		    NVQUIRK_HAS_PADCALIB,
 };
 
@@ -1422,6 +1426,7 @@ static const struct sdhci_pltfm_data sdhci_tegra114_pdata = {
 static const struct sdhci_tegra_soc_data soc_data_tegra114 = {
 	.pdata = &sdhci_tegra114_pdata,
 	.dma_mask = DMA_BIT_MASK(32),
+	.nvquirks = NVQUIRK_HAS_ANDROID_GPT_SECTOR,
 };
 
 static const struct sdhci_pltfm_data sdhci_tegra124_pdata = {
@@ -1438,6 +1443,7 @@ static const struct sdhci_pltfm_data sdhci_tegra124_pdata = {
 static const struct sdhci_tegra_soc_data soc_data_tegra124 = {
 	.pdata = &sdhci_tegra124_pdata,
 	.dma_mask = DMA_BIT_MASK(34),
+	.nvquirks = NVQUIRK_HAS_ANDROID_GPT_SECTOR,
 };
 
 static const struct sdhci_ops tegra210_sdhci_ops = {
@@ -1590,6 +1596,38 @@ static int sdhci_tegra_add_host(struct sdhci_host *host)
 	return ret;
 }
 
+static int sdhci_tegra_alternative_gpt_sector(struct mmc_card *card,
+					      sector_t *gpt_sector)
+{
+	unsigned int boot_sectors_num;
+
+	/* filter out unrelated cards */
+	if (card->ext_csd.rev < 3 ||
+	    !mmc_card_mmc(card) ||
+	    !mmc_card_is_blockaddr(card) ||
+	     mmc_card_is_removable(card->host))
+		return -ENOENT;
+
+	/*
+	 * eMMC storage has two special boot partitions in addition to the
+	 * main one.  NVIDIA's bootloader linearizes eMMC boot0->boot1->main
+	 * accesses, this means that the partition table addresses are shifted
+	 * by the size of boot partitions.  In accordance with the eMMC
+	 * specification, the boot partition size is calculated as follows:
+	 *
+	 *	boot partition size = 128K byte x BOOT_SIZE_MULT
+	 *
+	 * Calculate number of sectors occupied by the both boot partitions.
+	 */
+	boot_sectors_num = card->ext_csd.raw_boot_mult * SZ_128K /
+			   SZ_512 * MMC_NUM_BOOT_PARTITION;
+
+	/* Defined by NVIDIA and used by Android devices. */
+	*gpt_sector = card->ext_csd.sectors - boot_sectors_num - 1;
+
+	return 0;
+}
+
 static int sdhci_tegra_probe(struct platform_device *pdev)
 {
 	const struct of_device_id *match;
@@ -1616,6 +1654,10 @@ static int sdhci_tegra_probe(struct platform_device *pdev)
 	tegra_host->pad_control_available = false;
 	tegra_host->soc_data = soc_data;
 
+	if (soc_data->nvquirks & NVQUIRK_HAS_ANDROID_GPT_SECTOR)
+		host->mmc_host_ops.alternative_gpt_sector =
+				sdhci_tegra_alternative_gpt_sector;
+
 	if (soc_data->nvquirks & NVQUIRK_NEEDS_PAD_CONTROL) {
 		rc = tegra_sdhci_init_pinctrl_info(&pdev->dev, tegra_host);
 		if (rc == 0)
-- 
2.32.0