In intel-dg spi, there is no access to the spi controller,
the information is extracted from the descriptor region.

CC: Rodrigo Vivi <rodrigo.v...@intel.com>
CC: Lucas De Marchi <lucas.demar...@intel.com>
Signed-off-by: Tomas Winkler <tomas.wink...@intel.com>
Signed-off-by: Alexander Usyskin <alexander.usys...@intel.com>
---
 drivers/spi/spi-intel-dg.c | 190 +++++++++++++++++++++++++++++++++++++
 1 file changed, 190 insertions(+)

diff --git a/drivers/spi/spi-intel-dg.c b/drivers/spi/spi-intel-dg.c
index 8dc5448fc901..8ef9dccc9062 100644
--- a/drivers/spi/spi-intel-dg.c
+++ b/drivers/spi/spi-intel-dg.c
@@ -17,14 +17,197 @@ struct intel_dg_spi {
        void __iomem *base;
        size_t size;
        unsigned int nregions;
+       u32 access_map;
        struct {
                const char *name;
                u8 id;
                u64 offset;
                u64 size;
+               unsigned int is_readable:1;
+               unsigned int is_writable:1;
        } regions[];
 };
 
+#define SPI_TRIGGER_REG       0x00000000
+#define SPI_VALSIG_REG        0x00000010
+#define SPI_ADDRESS_REG       0x00000040
+#define SPI_REGION_ID_REG     0x00000044
+/*
+ * [15:0]-Erase size = 0x0010 4K 0x0080 32K 0x0100 64K
+ * [23:16]-Reserved
+ * [31:24]-Erase SPI RegionID
+ */
+#define SPI_ERASE_REG         0x00000048
+#define SPI_ACCESS_ERROR_REG  0x00000070
+#define SPI_ADDRESS_ERROR_REG 0x00000074
+
+/* Flash Valid Signature */
+#define SPI_FLVALSIG          0x0FF0A55A
+
+#define SPI_MAP_ADDR_MASK     0x000000FF
+#define SPI_MAP_ADDR_SHIFT    0x00000004
+
+#define REGION_ID_DESCRIPTOR  0
+/* Flash Region Base Address */
+#define FRBA      0x40
+/* Flash Region __n - Flash Descriptor Record */
+#define FLREG(__n)  (FRBA + ((__n) * 4))
+/*  Flash Map 1 Register */
+#define FLMAP1_REG  0x18
+#define FLMSTR4_OFFSET 0x00C
+
+#define SPI_ACCESS_ERROR_PCIE_MASK 0x7
+
+static inline void spi_set_region_id(struct intel_dg_spi *spi, u8 region)
+{
+       iowrite32((u32)region, spi->base + SPI_REGION_ID_REG);
+}
+
+static inline u32 spi_error(struct intel_dg_spi *spi)
+{
+       u32 reg = ioread32(spi->base + SPI_ACCESS_ERROR_REG) &
+                 SPI_ACCESS_ERROR_PCIE_MASK;
+
+       /* reset error bits */
+       if (reg)
+               iowrite32(reg, spi->base + SPI_ACCESS_ERROR_REG);
+
+       return reg;
+}
+
+static inline u32 spi_read32(struct intel_dg_spi *spi, u32 address)
+{
+       void __iomem *base = spi->base;
+
+       iowrite32(address, base + SPI_ADDRESS_REG);
+
+       return ioread32(base + SPI_TRIGGER_REG);
+}
+
+static int spi_get_access_map(struct intel_dg_spi *spi)
+{
+       u32 flmap1;
+       u32 fmba;
+       u32 fmstr4;
+       u32 fmstr4_addr;
+
+       spi_set_region_id(spi, REGION_ID_DESCRIPTOR);
+
+       flmap1 = spi_read32(spi, FLMAP1_REG);
+       if (spi_error(spi))
+               return -EIO;
+       /* Get Flash Master Baser Address (FMBA) */
+       fmba = ((flmap1 & SPI_MAP_ADDR_MASK) << SPI_MAP_ADDR_SHIFT);
+       fmstr4_addr = fmba + FLMSTR4_OFFSET;
+
+       fmstr4 = spi_read32(spi, fmstr4_addr);
+       if (spi_error(spi))
+               return -EIO;
+
+       spi->access_map = fmstr4;
+       return 0;
+}
+
+static bool spi_region_readable(struct intel_dg_spi *spi, u8 region)
+{
+       if (region < 12)
+               return spi->access_map & (1 << (region + 8)); /* [19:8] */
+       else
+               return spi->access_map & (1 << (region - 12)); /* [3:0] */
+}
+
+static bool spi_region_writeable(struct intel_dg_spi *spi, u8 region)
+{
+       if (region < 12)
+               return spi->access_map & (1 << (region + 20)); /* [31:20] */
+       else
+               return spi->access_map & (1 << (region - 8)); /* [7:4] */
+}
+
+static int intel_dg_spi_is_valid(struct intel_dg_spi *spi)
+{
+       u32 is_valid;
+
+       spi_set_region_id(spi, REGION_ID_DESCRIPTOR);
+
+       is_valid = spi_read32(spi, SPI_VALSIG_REG);
+       if (spi_error(spi))
+               return -EIO;
+
+       if (is_valid != SPI_FLVALSIG)
+               return -ENODEV;
+
+       return 0;
+}
+
+static int intel_dg_spi_init(struct intel_dg_spi *spi, struct device *device)
+{
+       int ret;
+       unsigned int i, n;
+
+       /* clean error register, previous errors are ignored */
+       spi_error(spi);
+
+       ret = intel_dg_spi_is_valid(spi);
+       if (ret) {
+               dev_err(device, "The SPI is not valid %d\n", ret);
+               return ret;
+       }
+
+       if (spi_get_access_map(spi))
+               return -EIO;
+
+       for (i = 0, n = 0; i < spi->nregions; i++) {
+               u32 address, base, limit, region;
+               u8 id = spi->regions[i].id;
+
+               address = FLREG(id);
+               region = spi_read32(spi, address);
+
+               base = (region & 0x0000FFFF) << 12;
+               limit = (((region & 0xFFFF0000) >> 16) << 12) | 0xFFF;
+
+               dev_dbg(device, "[%d] %s: region: 0x%08X base: 0x%08x limit: 
0x%08x\n",
+                       id, spi->regions[i].name, region, base, limit);
+
+               if (base >= limit || (i > 0 && limit == 0)) {
+                       dev_dbg(device, "[%d] %s: disabled\n",
+                               id, spi->regions[i].name);
+                       spi->regions[i].is_readable = 0;
+                       continue;
+               }
+
+               if (spi->size < limit)
+                       spi->size = limit;
+
+               spi->regions[i].offset = base;
+               spi->regions[i].size = limit - base + 1;
+               /* No write access to descriptor; mask it out*/
+               spi->regions[i].is_writable = spi_region_writeable(spi, id);
+
+               spi->regions[i].is_readable = spi_region_readable(spi, id);
+               dev_dbg(device, "Registered, %s id=%d offset=%lld size=%lld 
rd=%d wr=%d\n",
+                       spi->regions[i].name,
+                       spi->regions[i].id,
+                       spi->regions[i].offset,
+                       spi->regions[i].size,
+                       spi->regions[i].is_readable,
+                       spi->regions[i].is_writable);
+
+               if (spi->regions[i].is_readable)
+                       n++;
+       }
+
+       dev_dbg(device, "Registered %d regions\n", n);
+
+       /* Need to add 1 to the amount of memory
+        * so it is reported as an even block
+        */
+       spi->size += 1;
+
+       return n;
+}
+
 static void intel_dg_spi_release(struct kref *kref)
 {
        struct intel_dg_spi *spi = container_of(kref, struct intel_dg_spi, 
refcnt);
@@ -92,6 +275,13 @@ static int intel_dg_spi_probe(struct auxiliary_device 
*aux_dev,
                goto err;
        }
 
+       ret = intel_dg_spi_init(spi, device);
+       if (ret < 0) {
+               dev_err(device, "cannot initialize spi\n");
+               ret = -ENODEV;
+               goto err;
+       }
+
        dev_set_drvdata(&aux_dev->dev, spi);
 
        dev_dbg(device, "bound\n");
-- 
2.34.1

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