mtd: spi-nor: sfdp: Add support for SCCR map for multi-chip device

SCCR map for multi-chip devices contains the number of additional dice in
the device and register offset values for each additional dice.

spi_nor_parse_sccr_mc() is added to determine the number of dice and
volatile register offset for each die. The volatile register offset table
may already be allocated and contains offset value for die-0 via SCCR map
parse. So, we should use devm_krealloc() to expand the table with
preserving die-0 offset.

Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano@infineon.com>
Link: https://lore.kernel.org/r/89c892d52f8cbddbd14373f6a02db496885ae4f1.1680849425.git.Takahiro.Kuwano@infineon.com
Signed-off-by: Tudor Ambarus <tudor.ambarus@linaro.org>

diff --git a/drivers/mtd/spi-nor/sfdp.c b/drivers/mtd/spi-nor/sfdp.c
index 9d43e18d37705a7bf3febe59242a5cfd2f644d1c..b3b11dfed7893d84991a5da71b5702ee4d7a47c5 100644 (file)
--- a/drivers/mtd/spi-nor/sfdp.c
+++ b/drivers/mtd/spi-nor/sfdp.c
@@ -26,6 +26,11 @@
                                         * Status, Control and Configuration
                                         * Register Map.
                                         */
+#define SFDP_SCCR_MAP_MC_ID    0xff88  /*
+                                        * Status, Control and Configuration
+                                        * Register Map Offsets for Multi-Chip
+                                        * SPI Memory Devices.
+                                        */
 
 #define SFDP_SIGNATURE         0x50444653U
 
@@ -1264,6 +1269,63 @@ out:
        return ret;
 }
 
+/**
+ * spi_nor_parse_sccr_mc() - Parse the Status, Control and Configuration
+ *                           Register Map Offsets for Multi-Chip SPI Memory
+ *                           Devices.
+ * @nor:               pointer to a 'struct spi_nor'
+ * @sccr_mc_header:    pointer to the 'struct sfdp_parameter_header' describing
+ *                     the SCCR Map offsets table length and version.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spi_nor_parse_sccr_mc(struct spi_nor *nor,
+                                const struct sfdp_parameter_header *sccr_mc_header)
+{
+       struct spi_nor_flash_parameter *params = nor->params;
+       u32 *dwords, addr;
+       u8 i, n_dice;
+       size_t len;
+       int ret;
+
+       len = sccr_mc_header->length * sizeof(*dwords);
+       dwords = kmalloc(len, GFP_KERNEL);
+       if (!dwords)
+               return -ENOMEM;
+
+       addr = SFDP_PARAM_HEADER_PTP(sccr_mc_header);
+       ret = spi_nor_read_sfdp(nor, addr, len, dwords);
+       if (ret)
+               goto out;
+
+       le32_to_cpu_array(dwords, sccr_mc_header->length);
+
+       /*
+        * Pair of DOWRDs (volatile and non-volatile register offsets) per
+        * additional die. Hence, length = 2 * (number of additional dice).
+        */
+       n_dice = 1 + sccr_mc_header->length / 2;
+
+       /* Address offset for volatile registers of additional dice */
+       params->vreg_offset =
+                       devm_krealloc(nor->dev, params->vreg_offset,
+                                     n_dice * sizeof(*dwords),
+                                     GFP_KERNEL);
+       if (!params->vreg_offset) {
+               ret = -ENOMEM;
+               goto out;
+       }
+
+       for (i = 1; i < n_dice; i++)
+               params->vreg_offset[i] = dwords[SFDP_DWORD(i) * 2];
+
+       params->n_dice = n_dice;
+
+out:
+       kfree(dwords);
+       return ret;
+}
+
 /**
  * spi_nor_post_sfdp_fixups() - Updates the flash's parameters and settings
  * after SFDP has been parsed. Called only for flashes that define JESD216 SFDP
@@ -1480,6 +1542,10 @@ int spi_nor_parse_sfdp(struct spi_nor *nor)
                        err = spi_nor_parse_sccr(nor, param_header);
                        break;
 
+               case SFDP_SCCR_MAP_MC_ID:
+                       err = spi_nor_parse_sccr_mc(nor, param_header);
+                       break;
+
                default:
                        break;
                }