[PATCH 14/15] scsi: ufs: ufs-exynos: multi-host configuration for exynosauto

[Chanho Park <chanho61.park@samsung.com>]

UFS controller of ExynosAuto v9 SoC supports multi-host interface for I/O
virtualization. In general, we're using para-virtualized driver to
support a block device by several virtual machines. However, it should
be relayed by backend driver. Multi-host functionality extends the host
controller by providing register interfaces that can be used by each
VM's ufs drivers respectively. By this, we can provide direct access to
the UFS device for multiple VMs. It's similar with SR-IOV of PCIe.

We divide this M-HCI as PH(Physical Host) and VHs(Virtual Host). The PH
supports all UFSHCI functions(all SAPs) same as conventional UFSHCI but
the VH only supports data transfer function. Thus, except UTP_CMD_SAP and
UTP_TMPSAP, the PH should handle all the physical features.

This patch provides an initial implementation of PH part. M-HCI can
support up to four interfaces but this patch initially supports only 1
PH and 1 VH. For this, we uses TASK_TAG[7:5] field so TASK_TAG[4:0] for
32 doorbel will be supported. After the PH is initiated, this will send
a ready message to VHs through a mailbox register. The message handler
is not fully implemented yet such as supporting reset / abort cases.

Signed-off-by: Chanho Park <chanho61.park@samsung.com>
---
 drivers/scsi/ufs/ufs-exynos.c | 44 +++++++++++++++++++++++++++++++++++
 1 file changed, 44 insertions(+)

diff --git a/drivers/scsi/ufs/ufs-exynos.c b/drivers/scsi/ufs/ufs-exynos.c
index 82f915f7a447..30c12e97c665 100644
--- a/drivers/scsi/ufs/ufs-exynos.c
+++ b/drivers/scsi/ufs/ufs-exynos.c
@@ -83,6 +83,21 @@
 #define UFS_SHARABLE		(UFS_WR_SHARABLE | UFS_RD_SHARABLE)
 #define UFS_SHARABILITY_OFFSET	0x710
 
+/* Multi-host registers */
+#define MHCTRL					0xC4
+#define MHCTRL_EN_VH_MASK			(0xE)
+#define MHCTRL_EN_VH(vh)			(vh << 1)
+#define PH2VH_MBOX				0xD8
+
+#define MH_MSG_MASK				(0xFF)
+
+#define MH_MSG(id, msg)				((id << 8) | (msg & 0xFF))
+#define MH_MSG_PH_READY				0x1
+#define MH_MSG_VH_READY				0x2
+
+#define HCI_MH_ALLOWABLE_TRAN_OF_VH		0x30C
+#define HCI_MH_IID_IN_TASK_TAG			0X308
+
 enum {
 	UNIPRO_L1_5 = 0,/* PHY Adapter */
 	UNIPRO_L2,	/* Data Link */
@@ -173,6 +188,20 @@ static int exynosauto_ufs_drv_init(struct device *dev, struct exynos_ufs *ufs)
 	return 0;
 }
 
+static int exynosauto_ufs_post_hce_enable(struct exynos_ufs *ufs)
+{
+	struct ufs_hba *hba = ufs->hba;
+
+	/* Enable Virtual Host #1 */
+	ufshcd_rmwl(hba, MHCTRL_EN_VH_MASK, MHCTRL_EN_VH(1), MHCTRL);
+	/* Default VH Transfer permissions */
+	hci_writel(ufs, 0x03FFE1FE, HCI_MH_ALLOWABLE_TRAN_OF_VH);
+	/* IID information is replaced in TASKTAG[7:5] instead of IID in UCD */
+	hci_writel(ufs, 0x1, HCI_MH_IID_IN_TASK_TAG);
+
+	return 0;
+}
+
 static int exynosauto_ufs_pre_link(struct exynos_ufs *ufs)
 {
 	struct ufs_hba *hba = ufs->hba;
@@ -231,6 +260,19 @@ static int exynosauto_ufs_pre_pwr_change(struct exynos_ufs *ufs,
 	return 0;
 }
 
+static int exynosauto_ufs_post_pwr_change(struct exynos_ufs *ufs,
+					  struct ufs_pa_layer_attr *pwr)
+{
+	struct ufs_hba *hba = ufs->hba;
+	u32 enabled_vh;
+
+	enabled_vh = ufshcd_readl(hba, MHCTRL) & MHCTRL_EN_VH_MASK;
+
+	/* Send physical host ready message to virtual hosts */
+	ufshcd_writel(hba, MH_MSG(enabled_vh, MH_MSG_PH_READY), PH2VH_MBOX);
+
+	return 0;
+}
 
 static int exynos7_ufs_pre_link(struct exynos_ufs *ufs)
 {
@@ -1396,8 +1438,10 @@ static struct exynos_ufs_drv_data exynosauto_ufs_drvs = {
 				  EXYNOS_UFS_OPT_SKIP_CONFIG_PHY_ATTR |
 				  EXYNOS_UFS_OPT_BROKEN_RX_SEL_IDX,
 	.drv_init		= exynosauto_ufs_drv_init,
+	.post_hce_enable	= exynosauto_ufs_post_hce_enable,
 	.pre_link		= exynosauto_ufs_pre_link,
 	.pre_pwr_change		= exynosauto_ufs_pre_pwr_change,
+	.post_pwr_change	= exynosauto_ufs_post_pwr_change,
 };
 
 static struct exynos_ufs_drv_data exynos_ufs_drvs = {
-- 
2.32.0